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STFC-RAL-CR03-RAL-R61-2.01: Yeah, right? Well, the introduction is still introduction. I had to go back to the first page, I don't know.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, sorry for the very big delay, everyone. Let me introduce… What a day.

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STFC-RAL-CR03-RAL-R61-2.01: Can you go to the first slide, please.

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STFC-RAL-CR03-RAL-R61-2.01: Very similar slide, yeah. I think,

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STFC-RAL-CR03-RAL-R61-2.01: The first page, the internet. Before that, yes, this one, yeah. Okay.

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STFC-RAL-CR03-RAL-R61-2.01: So welcome to the seminar today. This is Nassim.

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STFC-RAL-CR03-RAL-R61-2.01: She's a research scientist at SNOLDA, and…

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STFC-RAL-CR03-RAL-R61-2.01: in Ontario, Canada, where she works on low background techniques for neutrino and dark matter experiments. She's a collaborator on the SNOW+, XLZB

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STFC-RAL-CR03-RAL-R61-2.01: and deep 360 experiments, and her main research is on developing ultra-low background radon detection and assay systems for these experiments.

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STFC-RAL-CR03-RAL-R61-2.01: Before joining SNOLA, she worked as a research associate at Triumph and Royal Holloway, University of London, and a postdoctoral fellow at Queen's University. She completed her PhD in Manchester University.

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STFC-RAL-CR03-RAL-R61-2.01: Which year, 2000. Okay. By the way. Yes. Okay, so, welcome.

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STFC-RAL-CR03-RAL-R61-2.01: And please, please calm down, you don't have to rush. No, I know, I tried to. Sorry, guys, for the technical issue, but I guess we can start. So, yeah, I'm going to talk about radon contour and measurement, at Snow Lab for quantum next-generation Radio Research Experiments. This might be a little bit

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STFC-RAL-CR03-RAL-R61-2.01: Different from what you…

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STFC-RAL-CR03-RAL-R61-2.01: work on a daily basis. So, introduction, I'm going to talk a little bit about nomadic method, and why searching for them is important.

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STFC-RAL-CR03-RAL-R61-2.01: And then talk about sources of background for this type of sessions, and then I'm focusing on redone that why it's really already is important.

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STFC-RAL-CR03-RAL-R61-2.01: Then, going to, turn a little bit technical, talking about the techniques which are applied in order to measure, radon ex-situ at a snow lab. So, components of experiments, you want them to be low radioactivity, so before you put

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STFC-RAL-CR03-RAL-R61-2.01: Building your experiment, you actually need to know, very similar level, what your background level is.

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STFC-RAL-CR03-RAL-R61-2.01: Then, a little bit talking about the radon remover techniques. Again, you want your experiment to be radon-free, so you need to basically develop techniques. For example, if you have liquid scintillator or, liquid arc or liquid xenone, you need to develop techniques to remove the radon from, from those.

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STFC-RAL-CR03-RAL-R61-2.01: Basically fluids, and then, talk about techniques to create lower radon environment for, like, assembling of, for example, the coupons, etc, and then summarize.

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STFC-RAL-CR03-RAL-R61-2.01: So,

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STFC-RAL-CR03-RAL-R61-2.01: So, basically, we know that during the Big Bang, there was a core amount of matter and antimicrobrod. So, the question is that why the world today, the universe today, looks like this, which basically is dominated by matter.

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STFC-RAL-CR03-RAL-R61-2.01: So, forecast of galaxies, stars, planets, light, rather than looking like this, where, like, you have an empty universe.

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STFC-RAL-CR03-RAL-R61-2.01: Where antimatter and matter emulated each other, they just created some energy, and by now, that energy is cooled down.

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STFC-RAL-CR03-RAL-R61-2.01: So, one thing is that can nutritional beta decay be the answer to this? So, nateobetr decay is a physics beyond a standard model.

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STFC-RAL-CR03-RAL-R61-2.01: is their own antiparticle.

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STFC-RAL-CR03-RAL-R61-2.01: And in that case, basically, you have one of the antineutrinos is observed as a neutrino, and the final stage of the normal,

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STFC-RAL-CR03-RAL-R61-2.01: A beta decay, and then in the final state, you have no antinodrinals, and you have only electrons. So, in this mechanism, it's a left… this will be a left-hand number violating process.

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STFC-RAL-CR03-RAL-R61-2.01: So it is a process which, basically annihilates onto particles, so that can actually be, basically one reason,

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STFC-RAL-CR03-RAL-R61-2.01: So, that, or path… it can be a path to understand why there is matter-on-to-matter, symmetry, in the, in the universe.

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STFC-RAL-CR03-RAL-R61-2.01: So experimentally, the way that we see this, we're looking at the energy sum of these two electrons, and in a normal

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STFC-RAL-CR03-RAL-R61-2.01: two-way decay, you basically have a continuum spectrum in a… if you have a story, you will see a, basically a mono energy peak, which is equal to some of these two electrons, which are estimated by the energy resolution of your detector.

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STFC-RAL-CR03-RAL-R61-2.01: This is an extremely rare process. It's, current experiments have a limit of 10 to 27 years half-life.

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STFC-RAL-CR03-RAL-R61-2.01: So, in comparison, as we all know, the universe is about 10 to 10 years, so you can see how rare this process is. So that's why you need very large-scale experiments, multi-tone fire, with very, very, very low background.

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STFC-RAL-CR03-RAL-R61-2.01: So, control in the background is, basically the name of the game for, for this, this extension.

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STFC-RAL-CR03-RAL-R61-2.01: So the other question, which we need to answer is, what is the nature of dark matter? There is a history of dark matter. I'm sure,

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STFC-RAL-CR03-RAL-R61-2.01: you know all about it. There are lots of evidences, but the most convincing evidence of dark matter is that when you look at the tiny variation of temperature of the universe 400,000 years after the Big Bang, and you basically map that.

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STFC-RAL-CR03-RAL-R61-2.01: You can, exactly, precisely calculate the components of the universe.

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STFC-RAL-CR03-RAL-R61-2.01: And what you see is that you have, about 26.8%

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STFC-RAL-CR03-RAL-R61-2.01: We don't matter. Only 4.9%, is there holding… Oops, sorry. Okay.

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STFC-RAL-CR03-RAL-R61-2.01: So, and the rest of it is dark energy, which will be understanding my less. So,

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STFC-RAL-CR03-RAL-R61-2.01: Right now, there are lots of parameters in space to look at for dark matter, and the TV scale dark matter, particles are basically similar, I'll be honest, not the model.

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STFC-RAL-CR03-RAL-R61-2.01: theory, and the Snow Lab, which I'm going to talk in a second, actually has so many experiments which are basically looking at different range of, these, these parameter aspects.

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STFC-RAL-CR03-RAL-R61-2.01: so…

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STFC-RAL-CR03-RAL-R61-2.01: So what… so background… controlling background is important. I have an example for a… for example, a dark matter experiment. So, basically, so what you expect is that the longer you run this experiment, so the longer exposure, you would expect that your sensitivity is improved, right?

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STFC-RAL-CR03-RAL-R61-2.01: But, the detective order of magnitude of, let's say, higher background, it reaches maximum sensitivity, like, much more sooner.

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STFC-RAL-CR03-RAL-R61-2.01: And there, doesn't really matter how long… how long more you run your experiment, you don't improve your sensitivity anymore.

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STFC-RAL-CR03-RAL-R61-2.01: So, right now, in the field, we reached to that level of flow background that

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STFC-RAL-CR03-RAL-R61-2.01: Next generation of experiments are talking about one event, one dark matter event, in 10 years of running the experiment.

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STFC-RAL-CR03-RAL-R61-2.01: So that's how rare, and that's why we call the rare events, that's such a rare thing. And then, when you're talking about one event in 10 years, then that means that you need to be back in a free environment.

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, so that's, that's a challenge.

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STFC-RAL-CR03-RAL-R61-2.01: So…

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STFC-RAL-CR03-RAL-R61-2.01: So now, where we're looking for this, we are… we are going deep underground, and the reason we're going deep underground for this, because immune blocks of underground labs are much less, so you're not worried about immune-induced background.

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STFC-RAL-CR03-RAL-R61-2.01: as much. So… so it's not a lab, this is a map

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STFC-RAL-CR03-RAL-R61-2.01: basically, in Canada. It's basically, situated 2 kilometers underground, an active mine, basically called, called Rayton Mine, near South Bay, Ontario.

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STFC-RAL-CR03-RAL-R61-2.01: So this is about 4, 4 average rides from Toronto for the people who don't know where Salbury is, so up north.

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STFC-RAL-CR03-RAL-R61-2.01: So, Estola, is, quite the second deepest undergrad, lab in the world. The first one is now a Chinese, Chinese lab,

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STFC-RAL-CR03-RAL-R61-2.01: Where, basically it's a ton… it's a… it's a lab that you drive… you basically drive your car to.

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STFC-RAL-CR03-RAL-R61-2.01: Whereas the snow lab is, actually… actually, you're going on the ground for kilometers, not on the tunnel or something. You actually have to get the cage and go down. So you see a picture of the surface building here, which also has some PIN labs in it, which some of these forecasts show is done, actually, making a surface lab.

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STFC-RAL-CR03-RAL-R61-2.01: So this is the map of the snow lab.

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STFC-RAL-CR03-RAL-R61-2.01: As you can see, it's quite big, big, big lab, and has lots of very large-scale experiments and plans for larger experiments, too. So you see the snow, the famous snow experiment, you see now a snow plots here.

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STFC-RAL-CR03-RAL-R61-2.01: And, we have a few dark matter experiments of SuperCPMS, PICO and others here. You basically have a, empty space right now in Coraupe, which we are hoping that we have a next-generation dark matter

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STFC-RAL-CR03-RAL-R61-2.01: Or making myself with a billboard, experimenter.

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STFC-RAL-CR03-RAL-R61-2.01: Okay. So,

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STFC-RAL-CR03-RAL-R61-2.01: I'm the collaborator of SNO Plus experiment, currently, and also XMCD, USCD Canadian groups are showing XLZD in last February, coming this February, so we are quite fresh.

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STFC-RAL-CR03-RAL-R61-2.01: And, so it's not plus is, 12 meter diameter and kilometers, so it's quite big. And currently, basically, it's a current generation known as our beta decay, a liquid scintillator.

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STFC-RAL-CR03-RAL-R61-2.01: They consider the experiment, and then XLZD is basically a future, don't matter, and I'm gonna start with the big experiment.

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STFC-RAL-CR03-RAL-R61-2.01: Okay.

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STFC-RAL-CR03-RAL-R61-2.01: So, now talking about background sources. So, what are backgrounds defined for us, for law energy… I call it law energy physicists? So,

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STFC-RAL-CR03-RAL-R61-2.01: So you, have gamas and vectors from national radioactivity, and also from national radioactivity, depending on, of course, what physics you're looking for, that would be the decay, or numerous, or dark matter,

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STFC-RAL-CR03-RAL-R61-2.01: What they create is different, and, you are basically sensitive, to, different energies, so different energies give, so you have backgrounds of the different energies.

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STFC-RAL-CR03-RAL-R61-2.01: So you can, for example, put dark matter, alpha in, so alpha interaction of alphas, which is a material which can create neutrons.

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STFC-RAL-CR03-RAL-R61-2.01: Can, give you, basically, signature of dark matter.

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STFC-RAL-CR03-RAL-R61-2.01: Surface outputs, again, for Dharmender experiments or problems, so what surface alpha can mean that Dharmender is rather than deposited in the detector, is deposited in a detector wall.

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STFC-RAL-CR03-RAL-R61-2.01: But it's very close to the surface of your, detection medium, and it's such a way that you don't see the energy of this oil power. What you see is the nuclei, the liquid nuclei.

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STFC-RAL-CR03-RAL-R61-2.01: And that basically, again, can mimic the dark matter.

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STFC-RAL-CR03-RAL-R61-2.01: Muels, mules reduce neutrons, and cosmogenic activation. Both of them can… they can be a problem for both elevated and dark matter experiments. Of course, we are underground and snow lab, so these are less problem… less problem for us.

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STFC-RAL-CR03-RAL-R61-2.01: So now, moving to redo… sorry, before going to redo. So, natural rate activity.

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STFC-RAL-CR03-RAL-R61-2.01: So we have 3, dictation… 3 important decades that

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STFC-RAL-CR03-RAL-R61-2.01: We are basically… need to make sure that they don't create natural, background in our detector. I'm focusing in, one of the more popular ones, which is uranium-238, and the reason… I prefer uranium-238 is because it's…

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STFC-RAL-CR03-RAL-R61-2.01: has, basically long-leave isotopes, which can be problematic. So, so you then break down this,

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STFC-RAL-CR03-RAL-R61-2.01: Chained to three parts.

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STFC-RAL-CR03-RAL-R61-2.01: And, all… these three parts can basically, depending on what you're looking for, can cause problems, in your experiments. But we divide them by, in three…

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STFC-RAL-CR03-RAL-R61-2.01: places, because it's, depend, based on the halftime. So, top of the uranium chain.

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STFC-RAL-CR03-RAL-R61-2.01: Basically, they are, we call them non-lean isotop, uranium chain.

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STFC-RAL-CR03-RAL-R61-2.01: the middle, which is Raven226, and radon-22, and protein E. We call them short-lived, basically, these are the short-lived part of the chain, while short-lived, so by long, I mean, more than thousands of years, while short, I mean in a matter of days and hours.

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STFC-RAL-CR03-RAL-R61-2.01: And then, after that, you'll have, basically this, this late to 10, which is, 22 years after, so again, from days and hours, they go 2 years.

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STFC-RAL-CR03-RAL-R61-2.01: And then… so the… this is maybe the third part.

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STFC-RAL-CR03-RAL-R61-2.01: So, each time that you have these, massive changes in half-life, there is a chance that you'll have a dystopram in the decay.

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STFC-RAL-CR03-RAL-R61-2.01: And that makes that you may basically know what your uranium content is, but that doesn't really, tell you that… what the background noise is, right?

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STFC-RAL-CR03-RAL-R61-2.01: So, so basically components processing can cause radioactive desequilibrium, and we therefore must study each subchain separately.

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STFC-RAL-CR03-RAL-R61-2.01: So…

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STFC-RAL-CR03-RAL-R61-2.01: So, for longer isotopes, one common technique is basically using, ICPMS. These are commercially available instruments. At the Snow Lab, we basically have one right now, which you see in the picture here.

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STFC-RAL-CR03-RAL-R61-2.01: And the sensitivity of these… these are quite sensitive devices, 0.1 macro backwards per kilogram.

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STFC-RAL-CR03-RAL-R61-2.01: But, but, yeah, this advantage… I mean, to our booth, but as I said, these advantages that you… it doesn't really, it can constrain your background, but it doesn't really give you information on what is lower in the chain.

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STFC-RAL-CR03-RAL-R61-2.01: For radon-26 and radon, radon polygeny, you can use high-perity germanium detectors. They have sensitivity of 10 to 100 microbaccura per sample, and you count it.

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STFC-RAL-CR03-RAL-R61-2.01: So you see, at the Snow Lab, we have, I think 6 of them, I believe, but I just had a picture of one of the more sensitive ones.

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STFC-RAL-CR03-RAL-R61-2.01: And, and also you have raised elimination systems, which have sensitivity of, depending on the detector, can be, 2200 macro.

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STFC-RAL-CR03-RAL-R61-2.01: I'm going to do, of course, this is a highlight of my talk, so I'm going to talk about that in a little bit.

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STFC-RAL-CR03-RAL-R61-2.01: And then, for the bottom of the chain, you basically need to, as you can see, there are lots of outputs here, so you can use, alpha spectroscopy to measure, to, to measure the, rates. Again, they are commercially, specialized, but commercially available.

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STFC-RAL-CR03-RAL-R61-2.01: equivalence, XOA, which is a reef chamber.

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STFC-RAL-CR03-RAL-R61-2.01: Can be used to, basically use tactics.

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STFC-RAL-CR03-RAL-R61-2.01: gran.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, so…

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STFC-RAL-CR03-RAL-R61-2.01: So now, radon emanation measurement. So, anything that, you put in your detector can emanate radon.

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STFC-RAL-CR03-RAL-R61-2.01: As I just talked about with uranium, what makes it unique compared to all other backgrounds is that it's a noble gas, so it can come.

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STFC-RAL-CR03-RAL-R61-2.01: So that makes it complicated, because then, if you see some background, then…

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STFC-RAL-CR03-RAL-R61-2.01: and somebody, some random purchasing background, then you don't really,

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STFC-RAL-CR03-RAL-R61-2.01: it doesn't assume that you can find where the source of background is, because it has trouble. So it emanates from material surface, so you basically can have, radon, basically, from record from the radion,

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STFC-RAL-CR03-RAL-R61-2.01: Or it can be, like, be more in-depth of a radium decay happens.

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STFC-RAL-CR03-RAL-R61-2.01: So, radon diffuses out from… for example, if you have very porous materials, then you can have, radon basically diffuses out, and then, what that does that mean, necessarily, what you see on the surface about radon is not necessarily what is actually in the pot.

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STFC-RAL-CR03-RAL-R61-2.01: And, yeah, so…

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STFC-RAL-CR03-RAL-R61-2.01: Also, at SOLA, the radon level is high. Underground, it's 120 background, like you with me here, just to compare.

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STFC-RAL-CR03-RAL-R61-2.01: Like, on surface, at Sudbury, it's, the level of radion is, 10 macro per…

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STFC-RAL-CR03-RAL-R61-2.01: Cubic meters, so this is a factor of 40 higher than surface.

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STFC-RAL-CR03-RAL-R61-2.01: it's not harmful for, it's not harmful for POMX, but it is definitely a problem for, our, our, experiment. So, AIC experiment needs to think about, a strategy to basically not having this problem, at least, amount of rhythm getting into the detector.

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STFC-RAL-CR03-RAL-R61-2.01: Okay.

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STFC-RAL-CR03-RAL-R61-2.01: So, and also, of course, we need to use low-oretical amenity material in our experiments, too.

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STFC-RAL-CR03-RAL-R61-2.01: So, how to remove radon? So, stick material selection for performing radon emanation measurements,

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STFC-RAL-CR03-RAL-R61-2.01: and regular amount of radon levels from different components of the detector, you may say, okay, you build a detector, the detector does that for you, can tell you what background you have. That's true, but sometimes some components of the experiment, such as external, some external, like, volume or something like that.

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STFC-RAL-CR03-RAL-R61-2.01: you don't have, a sensor there to actually measure, rhythm. So you need to assay that component, that, area, or different, metals.

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STFC-RAL-CR03-RAL-R61-2.01: You need to remove, radon from… if you have a, in the contents of talking about external plus and XLZZ, you need to basically remove the radon from the medium, the, from the medium which goes to your detector,

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STFC-RAL-CR03-RAL-R61-2.01: And you also need to control, radon ingress, especially at the SOLA, which has higher radon level.

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STFC-RAL-CR03-RAL-R61-2.01: So I'm going to… my talk is going to, basically cover some examples of each of these.

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STFC-RAL-CR03-RAL-R61-2.01: But also, you need to prevent surface contamination without, say, and cleaning and removal of surfaces,

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STFC-RAL-CR03-RAL-R61-2.01: especially for late to 10, which is a longer-lived half-life, you… if you expose, if you expose your experiment with some level of radon, and you know you did that, then you need to plan for how to remove the project. And, I don't have time to talk about it.

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STFC-RAL-CR03-RAL-R61-2.01: I can have… give example, about it, if people want to talk about it in the future.

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STFC-RAL-CR03-RAL-R61-2.01: So, Rakuten Access System right now, as it's now thinking about part of it, more thinking about it now, Rakuten Access System Access Power. So…

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STFC-RAL-CR03-RAL-R61-2.01: So, radar refers to the measurement of emanation rate, from a material or surface, and radon concentration in gas or water samples. You'll see a picture of, basically, four of the equipments that we have, which basically we use to measure radon rates.

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STFC-RAL-CR03-RAL-R61-2.01: I'm going to cover them.

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STFC-RAL-CR03-RAL-R61-2.01: So, we, basically, one tactic to use is the… I love to call it Rylon trapping tactic. So basically the way that it works is that you put your sample

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STFC-RAL-CR03-RAL-R61-2.01: In an emanation chamber, and, for example, you leave it for, one to two weeks.

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STFC-RAL-CR03-RAL-R61-2.01: On their back here. And why you put an elony… why you put an elamination chamber, for that long is because

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STFC-RAL-CR03-RAL-R61-2.01: They don't contact rain from the air can trapped in the, in your, your, material.

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STFC-RAL-CR03-RAL-R61-2.01: and, and have a slow, release. You want to separate what is, basically coming from the air in the course than, something that is actually the internal background of that, that, material.

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STFC-RAL-CR03-RAL-R61-2.01: So, yeah, so you put it for 2 weeks there, then, you then extract the radon, and, trap it in…

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STFC-RAL-CR03-RAL-R61-2.01: series that traps before it goes to your detector. And the way that you trap it is that you slow down radon atoms by, insert it in collagenic, liquids, typically liquid absorption.

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STFC-RAL-CR03-RAL-R61-2.01: And then, you want to travel up, and you transfer, basically the regular add-ons in, in your regular network.

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STFC-RAL-CR03-RAL-R61-2.01: Snow Lab is using, currently focusing on local sauce. I know that there are other technologies, and SnowLab also has other technologies, which I'm going to cover in a second, but, but, yeah, local sauce is the most, dominant, technology that we use right now.

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STFC-RAL-CR03-RAL-R61-2.01: So…

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STFC-RAL-CR03-RAL-R61-2.01: So this is a picture of the surface emanation system, for density of… so this is the emanation chamber I was talking about.

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STFC-RAL-CR03-RAL-R61-2.01: And you can, maybe see one of the traps there, and another trap there, and you can see a local cell being attached, so this is sort of a local cell confederacy attached here. It has a sensitivity of around 50 microbiacro, and, yeah, so,

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STFC-RAL-CR03-RAL-R61-2.01: What's the next slide?

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STFC-RAL-CR03-RAL-R61-2.01: So, Locasaw is a 2-inch diameter,

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STFC-RAL-CR03-RAL-R61-2.01: hemisphere, so, like, that, that big. And it's coated with zinc sulfide, which is, silver-activated, silver-activated zinc sulfide.

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STFC-RAL-CR03-RAL-R61-2.01: So, silver activates in suicide, scintillates with alpha particles, it's an in- it's, in, it's an inorganic scintillator.

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STFC-RAL-CR03-RAL-R61-2.01: And it makes it ideal for detection.

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STFC-RAL-CR03-RAL-R61-2.01: So, at Sona, we have 16 local channels, and basically, we put the locusts on top of

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STFC-RAL-CR03-RAL-R61-2.01: two-inch PMTs, to basically do the counting.

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STFC-RAL-CR03-RAL-R61-2.01: and you see, basically, and typical alpha bars, this is, to know, to understand, so this is sample number, this is the sample number, but this is a form of a second window, so this is a,

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STFC-RAL-CR03-RAL-R61-2.01: I don't know what type of facility that they're working on, but working with, but this is, like, so I can't say it's explore.

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STFC-RAL-CR03-RAL-R61-2.01: of course, when you're doing radon detection, you need to know the efficiency,

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STFC-RAL-CR03-RAL-R61-2.01: So, there has been, two efficiency measurements of local cells, which were published, and recently, we also did fully John 4 simulation, basically, of the post, authentic cells.

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STFC-RAL-CR03-RAL-R61-2.01: And as you can see, one of the measurements is to have tension with the, with the simulation and audio measurement.

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STFC-RAL-CR03-RAL-R61-2.01: we are planning to… the measurement's done somewhere… it was basically done at 20s or something like that. We are trying to actually do that Snow Lab again, too, with a much lower… lower instance, a lower concentrated source.

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STFC-RAL-CR03-RAL-R61-2.01: But hopefully these arrow bars, go a little bit lower than what you see there. Hopefully they have a better measurement.

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STFC-RAL-CR03-RAL-R61-2.01: So, now, background. So, efficiency, I always, again, to question you, what is the background? When I set 50 macro background system, the… the domain backgrounds actually developed as a background compared to the rest of the system.

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STFC-RAL-CR03-RAL-R61-2.01: So… so the way that we do it is that we purchase the Zoom sulfide from, basically from a company.

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STFC-RAL-CR03-RAL-R61-2.01: And, the new basic… and we look… we've already done the study, and we know that the main background is coming from things like Zephyr and the Adyeca, for example, we are using.

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STFC-RAL-CR03-RAL-R61-2.01: So new requests that have background of 3 to 5 alpha counts per day, and

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STFC-RAL-CR03-RAL-R61-2.01: As I was talking about, Lecture 10, which has a 22-year half-life and is supporting Lecture 10, so that means that when you're doing, the more, more and more assets you're doing.

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STFC-RAL-CR03-RAL-R61-2.01: you're starting to build background. So that's why the age, so when you look across the stages, and also depending on what you were emanating, some of them, some of these you were emanating was quite, radioactive.

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STFC-RAL-CR03-RAL-R61-2.01: Then you can have local cells which are really high background. So right now, we have about 10 local cells around here, which are the newer local cells that we are using for price-sensitive measurements, and the rest we're not really using, apart from when we want to do channel calibration and, or, troubleshooting.

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STFC-RAL-CR03-RAL-R61-2.01: So we have to make new passes every few years. For example, this is one of the new passes that we made, last year. And we basically, tried to, develop the procedure to do it live.

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STFC-RAL-CR03-RAL-R61-2.01: Now we are doing, research and development, so, I'm sure…

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STFC-RAL-CR03-RAL-R61-2.01: One of the questions that you might have asked in your head is that, okay, you're saying all this, but what your goal is? How long you want to go.

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STFC-RAL-CR03-RAL-R61-2.01: Especially when you're talking about law background.

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STFC-RAL-CR03-RAL-R61-2.01: So, XCD goal right now is that, the radar level inside the liquid xenon target has to be less than 0.1 macromacromic kilogram.

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STFC-RAL-CR03-RAL-R61-2.01: And, I just told you that our system is 50 microbi per sample.

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STFC-RAL-CR03-RAL-R61-2.01: So, that means that we need to, reduce… for the next generation of experiments, we need to reduce background by factor of 100.

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STFC-RAL-CR03-RAL-R61-2.01: And that's what… right now, that's what my group is focusing on. So we are working on,

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STFC-RAL-CR03-RAL-R61-2.01: doing RMS for lower background 625. So you see, we had the first test, and what you, what you see is that, basically this year, and, we have the, we have mixed scintillators,

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STFC-RAL-CR03-RAL-R61-2.01: And you can see this is basically the all-up part from the single list that we made. But, the loyalty, is about a factor of two lower than what we see in the commercial one, so we are still trying to do, more, or if you understand what we are doing wrong.

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STFC-RAL-CR03-RAL-R61-2.01: In addition, we are also, having, developing, spherical proportional conscious, I don't know how many of your formula with the UC technology, or dark sphere technology, but basically, yeah, so, so this would be a…

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STFC-RAL-CR03-RAL-R61-2.01: much smaller scale, compiled with local saw and, promotion and methods.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, so, the other technique, so this all happens in the category of traveling, traveling technique, but the only technique that we can use to measure radon is, what I would like it, call a recirculation thing.

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STFC-RAL-CR03-RAL-R61-2.01: And that is that rather than trapping your radon, you basically, you put your radon sample in a chamber, and then you basically recirculate it with some carrier gas, and then that radon reaches to your, basically, the detector.

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STFC-RAL-CR03-RAL-R61-2.01: Which, then can measure the radar level continuously.

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STFC-RAL-CR03-RAL-R61-2.01: So these are the electrostatic chambers, so, which are basically, have a… they have a dialogue, which are,

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STFC-RAL-CR03-RAL-R61-2.01: detector, and basically you give it a high voltage, and that's how you… you measure the ice.

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STFC-RAL-CR03-RAL-R61-2.01: So these are called, so Snow developed this, they are not, sensitive compared to our, other, system that I was talking about. So we are just bringing them back online, because they have not been used for a while.

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STFC-RAL-CR03-RAL-R61-2.01: And we are trying to see whether we can improve the system in such a way that to reduce the background.

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STFC-RAL-CR03-RAL-R61-2.01: So, how much time do I have? Please carry on. Okay.

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STFC-RAL-CR03-RAL-R61-2.01: So, we want to also, be able to measure radon concentration in non-fersion gas. So non-fusion is widely used as a cover gas to prevent radon ingress in the detector. So, this is, for example, the top of the loss detector, top of the neck.

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STFC-RAL-CR03-RAL-R61-2.01: And this is in Linacre system, basically. And, or sometimes, when you want to do an emulation of a very big component of an experiment.

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STFC-RAL-CR03-RAL-R61-2.01: Just…

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STFC-RAL-CR03-RAL-R61-2.01: Putting vacuum doesn't talk, so you need to fill that up with nitrogen again, and then, blushing, and then a pump in another to measure the radon level in that component. This is an example of what we did at the Snow Lab, which is, like, people 500, steel shelf, and wanted to see what radon amimension it has.

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STFC-RAL-CR03-RAL-R61-2.01: So the system to do that, we basically use a similar system that I just described earlier, similar technology, and you wrap it up in an engine chamber, then you have a cover-cast system, which

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STFC-RAL-CR03-RAL-R61-2.01: Feed, with node version, and you'll basically, cut the radium atom and, measured.

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STFC-RAL-CR03-RAL-R61-2.01: So, we had to go, through an upgrade for this, basically, this system that we have on the ground.

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STFC-RAL-CR03-RAL-R61-2.01: And because of the trap.

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STFC-RAL-CR03-RAL-R61-2.01: the Raven trap was made of bronze wool, and what we found out is that, bronze wool or oil are very good for regular eminations on the vacuum. They actually… what we saw is that as, we do longer asset time, longer asset time is that

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STFC-RAL-CR03-RAL-R61-2.01: As you extract more nitrogen going through the system to sample it, you see that the efficiency is dropping.

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STFC-RAL-CR03-RAL-R61-2.01: So, that was limiting our sensitivity, and before the experimental needs.

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STFC-RAL-CR03-RAL-R61-2.01: So, we basically needed to develop a new rhythm trap for this measurement, so we used an activated charcoal trap. We added an activated charcoal trap to the system. We had to do…

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STFC-RAL-CR03-RAL-R61-2.01: And for Adye to basically remove the background of this, Adye charcoal, which was, coconut-based, using the nitric acid exchange.

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STFC-RAL-CR03-RAL-R61-2.01: And we got, relatively good rate of low rate of emanation of 18 millivar kilogram.

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STFC-RAL-CR03-RAL-R61-2.01: In comparison, before we did this, basically, basically we reduced the factor of 10, the lack of this.

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STFC-RAL-CR03-RAL-R61-2.01: And then we tested this trap, and the way that I would test it is that… test any random trap, is that you would need a calibration source, your fluid enough protein.

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STFC-RAL-CR03-RAL-R61-2.01: To that, and then you basically, see how much radon you can, drop and extract.

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STFC-RAL-CR03-RAL-R61-2.01: So… If you compare this with,

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STFC-RAL-CR03-RAL-R61-2.01: borrowing school, that's what we found out is that under the borrowing school, which the efficiency drops with, with charcoal trap, efficiency is just constant. So we, currently have extensive review of non-microbial microbes miterap, and we're doing as an… we don't have the answer. This is…

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STFC-RAL-CR03-RAL-R61-2.01: This system is submission for external system at SOLA, but, for XSVD, again, we absolutely need to go lower. So we are basically continuing this research, basically trying to find, lower background activated charcoal.

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STFC-RAL-CR03-RAL-R61-2.01: but the method I've developed

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STFC-RAL-CR03-RAL-R61-2.01: is, already being used, by other experiments, so I saw that circulation of this experiment has gone up for other… for different… was different experiments, too.

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STFC-RAL-CR03-RAL-R61-2.01: So… Now, Water recognizance system, so, you, so…

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STFC-RAL-CR03-RAL-R61-2.01: For example, the Snow Plus is covered with, 7,000 tons of ultra-fuel water as shielded.

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STFC-RAL-CR03-RAL-R61-2.01: And, external ISMO214, which comes from radon, it's a direct background of Nocturnal status, so knowing that the radon level is, is, important. It can also be a background to the solar nocturnal search.

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STFC-RAL-CR03-RAL-R61-2.01: So, we basically have, again, very similar, similar system, but in addition to what I was talking about, we have a degasser.

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STFC-RAL-CR03-RAL-R61-2.01: and the water trap. So, basically, what happens is that you'll have,

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STFC-RAL-CR03-RAL-R61-2.01: UPW coming from, either the cavity or from the UPW, purification plant itself.

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STFC-RAL-CR03-RAL-R61-2.01: And, you basically then, it sprays to this, what we call, vacuumic acid, so it's a big chamber, which is, which is under vacuum. So you extract the radon atoms with a little bit of,

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STFC-RAL-CR03-RAL-R61-2.01: UPW, then you trap the UPW, and then the rest is familiar, right? All of them have similar design, and then you basically,

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STFC-RAL-CR03-RAL-R61-2.01: polygular atoms.

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STFC-RAL-CR03-RAL-R61-2.01: We don't do this that often, and the reason for that we don't need to. When we are doing this, is when, for example, recirculation is changing in the snow plus cavity, and we want to see how much… how much that is affecting the background of, water quality. Or the pump is broken, they put in a new pump, you want to know what is the effect of that.

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STFC-RAL-CR03-RAL-R61-2.01: So, for example, so these data points that you see, it's basically from a port, which is between the athletic cell of a snowfloss and the PMTS structure. So it's extend… so basically between these two, so it's, external to the athletic result.

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STFC-RAL-CR03-RAL-R61-2.01: And what you see here, is basically, this is the targeted, targeted value we wanted to see, and, and that's it. These are the numbers that we see, which is, 10 to minus 30, 10 to minus 13 gram of.

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STFC-RAL-CR03-RAL-R61-2.01: uranium to gram of, water per white.

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STFC-RAL-CR03-RAL-R61-2.01: So, yeah. So, we are some major,

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STFC-RAL-CR03-RAL-R61-2.01: the… the Yopita Bayou radioactivity, which other experiments…

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STFC-RAL-CR03-RAL-R61-2.01: Apart from the snow pelos, maybe you want to know that number, and that number is actually 10 to minus 14, I didn't write that. It's 10 to minus 14, so one order of magnitude is lower than what you see in the snow pelos cavity, which is if you want to…

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STFC-RAL-CR03-RAL-R61-2.01: Think about the matter of radon atoms, that's basically 294 radon atoms per liter.

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STFC-RAL-CR03-RAL-R61-2.01: So, regular removal techniques?

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STFC-RAL-CR03-RAL-R61-2.01: So the,

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STFC-RAL-CR03-RAL-R61-2.01: This is, again, focused on cardogenic, chirogenic, materials, such as, for example, XLZDD. You have,

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STFC-RAL-CR03-RAL-R61-2.01: Few ways to do… to remove radon, from, for example, the cuisine or liquid. One way is to use, distillation technique.

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STFC-RAL-CR03-RAL-R61-2.01: Basically, you have… because different, radon has different boiling points compared to liquids, compared to, like, gases, you know, acid arcolor.

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STFC-RAL-CR03-RAL-R61-2.01: So you, basically, by, by,

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STFC-RAL-CR03-RAL-R61-2.01: Having a heater and condenser, you can make sure that the radon stays in the bottom, whereas, boiler, basically liquid or gas, goes to the condenser, and then that's where you can purify it.

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STFC-RAL-CR03-RAL-R61-2.01: You can… oh, the other technique you can use is the physical absorption. I already talked about charcoal. The difference now is that in previous examples, charcoal, you want to also extract the ribbon atoms. In this example, you just want rigonatoms to stay there, so you need to make very big, very long steps in order to do that.

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STFC-RAL-CR03-RAL-R61-2.01: And, when you're using activated charcoal, you also need to go, cold again. So you need to think about, again, designing some callergenic system to cool down this activated charcoal.

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STFC-RAL-CR03-RAL-R61-2.01: The other thing which is newer in the field, is, you can use silver exchange zone, right? And the thing about silver exchange Zero is that you can actually run them in room temperature.

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STFC-RAL-CR03-RAL-R61-2.01: And, already work has been done in order to apply for liquid carbon and also world of nitrogen. So this is basically, the nature paper, which Chris mentioned.

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STFC-RAL-CR03-RAL-R61-2.01: As based on my knowledge, about selections that work as radon removal. What you see in this plot is the radon concentration versus the

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STFC-RAL-CR03-RAL-R61-2.01: Breakthrough time, so what does that breakthrough time means that the longer this time is, means that it took longer for radio to, to come out of your trap. So that means that you're more efficient in trapping, trapping radio.

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STFC-RAL-CR03-RAL-R61-2.01: So what you see is that this is an activated charcoal.

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STFC-RAL-CR03-RAL-R61-2.01: And it says… Basically,

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STFC-RAL-CR03-RAL-R61-2.01: Different, the blue is, one, Zola from one company, and there are different colors, Zola from other companies. And what you see is that, you see, backdrop 10 to 100, increase in hydrosion efficiency.

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STFC-RAL-CR03-RAL-R61-2.01: Compared to activity sharp offer, same body, all of these use the same amount of, this…

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STFC-RAL-CR03-RAL-R61-2.01: this method does. So it's no lab is, basically slowly, trying to basically test this material for,

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STFC-RAL-CR03-RAL-R61-2.01: For removing, radon,

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STFC-RAL-CR03-RAL-R61-2.01: And we are also collaborating… I'm gonna adjun from, sort of, please, too, so we are collaborating with chemists at, Coons University to basically,

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STFC-RAL-CR03-RAL-R61-2.01: tune this, zeodite for us, or removing, Kratom from Xenon.

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STFC-RAL-CR03-RAL-R61-2.01: So these are the plots showing that, like, basically the breakthrough time, of, radio in different gases, sorry, when you're uploading to different gases.

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STFC-RAL-CR03-RAL-R61-2.01: And again, it seems that, like, argon is really good. It's really good to remove radon from argon. I just said, the longer, the better. there is no data for xenon, and the reason there is no data for xenone is because I… I think…

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STFC-RAL-CR03-RAL-R61-2.01: Xenon possibly gets trapped in this, in this cell, cell-like too. So that's why you need to do a research to see how you can trap, phon, but not xenon.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, so I think it's towards the end now. So, also, so when you are

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STFC-RAL-CR03-RAL-R61-2.01: As embedding a component of your detector, you need to do it in radon reduced environment,

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STFC-RAL-CR03-RAL-R61-2.01: So you can… one way to achieve that is to make,

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STFC-RAL-CR03-RAL-R61-2.01: columns of activated charcoal, and then you basically, blow, the air into this activated charcoal, and the output… the output basically gives you a lower radon, basically emanating air.

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STFC-RAL-CR03-RAL-R61-2.01: So that's how super CDMS at Sona, that's, basically, that's the technique they use, and they could achieve less than 0.1 back foot per cubic meter.

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STFC-RAL-CR03-RAL-R61-2.01: So Snow Lab, basically, Snow Lab is needed, also for future long list, projects.

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STFC-RAL-CR03-RAL-R61-2.01: possibly even begin. Beginner. There we go.

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STFC-RAL-CR03-RAL-R61-2.01: I already talked about nitrogen used as a cover gas system. Again, one way to keep radon out from your detector is to work on a nitrogen perdage environment. So at the SOA now, we actually have

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STFC-RAL-CR03-RAL-R61-2.01: a liquid nodrogen plant underground. I'm not sure whether it's a deepest liquid nitrogen plant underground or not, I have no idea, but, Reis it is quite deep, 2 kilometers. But, so this provides liquid nodrogen, and roll-off operation to, our germanium sectors, as well as the snowflops environment.

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STFC-RAL-CR03-RAL-R61-2.01: We did measure recently of this, as Tom in the back of the Q&A, and, we want to actually achieve lower than this, so we're thinking about plans of how to make this, reasonable longer.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, so I think this is the Skype for a summary. I didn't want… I wanted to mention this as well, because I don't think this is, known that much outside. We are just writing publication about it, so hopefully it becomes a bit more and more.

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STFC-RAL-CR03-RAL-R61-2.01: So SNO Plus, is using… this is a picture of me when I was a postdoc. SNO Plus is, using,

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STFC-RAL-CR03-RAL-R61-2.01: basically a unique color gas system. So, one problem that we have in the mine, at the snow lab, is that we have

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STFC-RAL-CR03-RAL-R61-2.01: pressure fluctuation of, about 10%, 9%, 10%. And the problem with that pressure fluctuation is that, sodium… sodium pressure fluctuation can actually, damage equipment and damage, defectors. It's no clause.

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STFC-RAL-CR03-RAL-R61-2.01: Has, it's a 12 meter diameter act in it, which has a niche.

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STFC-RAL-CR03-RAL-R61-2.01: And basically, engineering calculation shows that the net should not be exposed to that 9% pressure fluctuation.

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STFC-RAL-CR03-RAL-R61-2.01: So, naive, solution for not making… to make sure that Reagan doesn't get in is to just steal the top of your gettor. But we cannot just steal the top of your debtor, because then you don't… you cannot adjust for the facial change, and that will break your neck.

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STFC-RAL-CR03-RAL-R61-2.01: So that's why, we basically designed the flexible backs, which basically, they can breathe and how when their pressure changes, from low radon material, of course, because that was important.

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STFC-RAL-CR03-RAL-R61-2.01: And, I like to call them a long pulp as not blows, because they're exactly like longs, they, basically breathe in and out.

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STFC-RAL-CR03-RAL-R61-2.01: And, we could, basically reach the, sensitivity of 01 backward in cubic meter width.

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STFC-RAL-CR03-RAL-R61-2.01: And this is, basically, makes the requirement for data detective search of, visits, and, but it's not… if you want to do more research stolen entrepreneur, we actually need to go a bit lower than that.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, so…

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STFC-RAL-CR03-RAL-R61-2.01: So, to summarize, external operator experiments profile the mental question in particle physics, and control radar in this background is critical to actually increase scores,

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STFC-RAL-CR03-RAL-R61-2.01: SNOLA continues to strengthen its radon mitigation program by building and operating low-background radon access systems, or on each one making low-background radon counting systems.

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STFC-RAL-CR03-RAL-R61-2.01: And developing advanced radon removal techniques, creating radon-reduced environment, the boil of nitrogen.

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STFC-RAL-CR03-RAL-R61-2.01: And we also have to maintain existing radar systems. this, of course, was Workout

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STFC-RAL-CR03-RAL-R61-2.01: So many,

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STFC-RAL-CR03-RAL-R61-2.01: graduate students and master's students, they were basically working on this, so… Yeah, thank you. Yes, thank you.

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STFC-RAL-CR03-RAL-R61-2.01: Thank you for the very…

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STFC-RAL-CR03-RAL-R61-2.01: Are there questions? And thanks, everyone, for sticking to the end this morning. She has one within 50 minutes, so yes, we'll find out the delay in the beginning, but yes. Are there any questions on Zoom phones?

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STFC-RAL-CR03-RAL-R61-2.01: I don't see yet any, here in the room.

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, I had a question about…

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STFC-RAL-CR03-RAL-R61-2.01: your samples, when you put them in the detectives. So you mentioned the…

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STFC-RAL-CR03-RAL-R61-2.01: Because of, like, the difference between the surface stuff and the stuff that comes from the center.

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STFC-RAL-CR03-RAL-R61-2.01: With the geometry of the samples that you create, whether you've got, like, quite a dense sample, whether you've got a plane of a sample.

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STFC-RAL-CR03-RAL-R61-2.01: That could probably change your…

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STFC-RAL-CR03-RAL-R61-2.01: your results significantly. So how do you control and make the geometry of your samples representative of the thing that you're trying to

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STFC-RAL-CR03-RAL-R61-2.01: So sometimes you need to make a dedicated… so depending on what time… so, for example, let's say you want to measure cables, like, I would say for cables, you possibly want to make a very long tube and put your cables there, as an example, and it's matching that geometry.

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STFC-RAL-CR03-RAL-R61-2.01: So that's one way to, yeah, that's one way. The other way is that we are already doing two measurements, by lamp one. So, the hope is that the second measurement is more accurate, and it's the diffusion by that is, like, basically came out.

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, so we usually throw out the first measurement, but keep the second measurement. If it's like, if the first and second measurement are so different that it affects what we are reporting to the experiment, then you'll have to do the third one. That's why this

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STFC-RAL-CR03-RAL-R61-2.01: I've really toned it down, but it can take a month to do a measure. It's easy, or even long.

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STFC-RAL-CR03-RAL-R61-2.01: Yes, absolutely. Thank you for the talk, very interesting. I have a question again in the lower ground radon counting system. You mentioned zinc sulfide, so…

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STFC-RAL-CR03-RAL-R61-2.01: that's a wide-engaged material like others. I don't know exactly, I don't recall what they eel.

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STFC-RAL-CR03-RAL-R61-2.01: the photon yield of zinc sulfide is, but have you considered, for example, using gallium nitronide, that also has a similar band gap.

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STFC-RAL-CR03-RAL-R61-2.01: Compared to zinc sulfide, and I suspect… Gallium nitride, and I think it would be even lower.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, I, yeah, I can look at that, yeah. We are, zinc so far, it's just that because it was something that's, I guess, a snow legacy, and we want to see whether we can purify it, but yeah, I mean…

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STFC-RAL-CR03-RAL-R61-2.01: The plan is to make something better than our Kristenity, so I will… that's, that sounds…

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, I imagine that the yield… If it's inorganic, I guess, you know, yeah, it is inorganic, too, right? Yeah, it's a semiconductor. I'm saying, I think the yield is similar, so I'm talking to the 5 visible photons, fairly big, which is what I mean.

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STFC-RAL-CR03-RAL-R61-2.01: Another fund. So, I might imagine that given that it's more developed as a semiconductor technology compared to things so far, it might actually be kind of better.

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STFC-RAL-CR03-RAL-R61-2.01: Excuse me.

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STFC-RAL-CR03-RAL-R61-2.01: Do you think the purification of it is easy, do you think? Well, they use it routinely in semiconductor industry, so the fabrication process obviously takes place in a very highly controlled

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STFC-RAL-CR03-RAL-R61-2.01: environment, so I would imagine that in terms of PR, it is probably better. Okay, so fine.

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STFC-RAL-CR03-RAL-R61-2.01: Okay, thank you.

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STFC-RAL-CR03-RAL-R61-2.01: And in Canada, you also have NRC, which has a long, addition.

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STFC-RAL-CR03-RAL-R61-2.01: In developing and working with gallon nitride material.

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STFC-RAL-CR03-RAL-R61-2.01: I think it's only 4 hours' drive from you.

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STFC-RAL-CR03-RAL-R61-2.01: Sorry, sorry, where… where did you say in Canada? National Movies, St. National Research Center. Yeah.

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STFC-RAL-CR03-RAL-R61-2.01: Here, Carlton University. Okay.

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STFC-RAL-CR03-RAL-R61-2.01: Thank you. Thank you very much.

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STFC-RAL-CR03-RAL-R61-2.01: I had a really silly question. The… the 9% pressure difference over Snow Lab, is that just general use, or is that, like, when you have a power cut, and the…

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STFC-RAL-CR03-RAL-R61-2.01: systems go down. It can be ventilation, sometimes problem, power cut, yeah, mainly power cards, you can have liquids, not liquid, sorry, system damage is not liquid or black, because you are underground and rocks can, like, crack and burst.

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STFC-RAL-CR03-RAL-R61-2.01: That type of thing can cause… Oh, change of pressure.

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, yeah. I just remember, like, when the power cuts went, my ears just went… Yeah, yeah, yeah.

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STFC-RAL-CR03-RAL-R61-2.01: Sorry. Yeah, I saw you at the moment. I saw you somewhere.

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STFC-RAL-CR03-RAL-R61-2.01: Can I, ask, so in your system, you've got two, radon traps, the primary, and then… why is that?

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STFC-RAL-CR03-RAL-R61-2.01: It's because of the local cell geometry. You… if you, your trap is big and local cell is, like, small, so if you want the efficiency to be maximum, you need to concentrate regular atoms to a trap which is a smaller volume than the locusa. But why do we need two? So, second one is, very…

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STFC-RAL-CR03-RAL-R61-2.01: The first… the second one we call a concentration trap is the one that's much smaller than the first of all.

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STFC-RAL-CR03-RAL-R61-2.01: Does that make sense?

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STFC-RAL-CR03-RAL-R61-2.01: So, you would draw if you want.

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STFC-RAL-CR03-RAL-R61-2.01: That's possible. So… oh.

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STFC-RAL-CR03-RAL-R61-2.01: There are skits, skits there. Yeah, I could have time.

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STFC-RAL-CR03-RAL-R61-2.01: So, I think Lo Croissant, so low croissant, I think, has, if I don't remember correctly, is 30 centimeter

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STFC-RAL-CR03-RAL-R61-2.01: Healed by Daniel?

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STFC-RAL-CR03-RAL-R61-2.01: Whereas, like, your first fab.

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STFC-RAL-CR03-RAL-R61-2.01: is, like, I have to do the calculation, but it's almost, like, almost a backdrop in volume compared to the album.

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STFC-RAL-CR03-RAL-R61-2.01: So, it's much lower volume. So, that means that your efficiency, if you do volume sharing.

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STFC-RAL-CR03-RAL-R61-2.01: to… to basically go there, then your efficiency will be, like, one thing. Yeah, I understand that. It's just, so you've got two, so you want to concentrate the concentrated, just to get a higher…

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, that's right. Otherwise, if you use this from the beginning, then this is not big enough to trap your radon atoms. Okay. So you need something bigger and more forest to trap radon atoms, and then you need a second.

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STFC-RAL-CR03-RAL-R61-2.01: But it's a very good point. So, if you have a bigger detector, see, this is optimized with John 4, to, for example, have this design. If you have a bigger detector, then this problem goes away, right? So, for example, people using big electrostatic chambers, they don't have that problem as much.

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, so this is because… this is basically, yeah, related to the geometry of the bus.

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STFC-RAL-CR03-RAL-R61-2.01: Thanks.

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STFC-RAL-CR03-RAL-R61-2.01: I would like to ask, are there other labs in the world that do similar research?

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, radon, it's very… so, all the underground labs have more or less, moving twice, same type of research. They all have systems, and they're all thinking about how I can make this more

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STFC-RAL-CR03-RAL-R61-2.01: Basically, high sensitivity for next generation. Okay. The more we… I was bored with misbeigans, saw this stuff, yeah. But the more you… you need to have more of them in the world, because, as I said, one measurement takes them one month.

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STFC-RAL-CR03-RAL-R61-2.01: Two months, and then you have to have lots of, lots of,

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STFC-RAL-CR03-RAL-R61-2.01: Components of experiment, lots of candidates, of which one you want to use, then you want to do it as fast as possible.

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STFC-RAL-CR03-RAL-R61-2.01: Yes, and as far as I understand, you have not reached your goal yet. No, we have. So… We reached for the current experiment? For the car. Yes. Yeah, so… So,

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STFC-RAL-CR03-RAL-R61-2.01: Do you think this goal is realistic, and whether more research would help?

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STFC-RAL-CR03-RAL-R61-2.01: Yeah, so, I think, I think it's realistic, the research material science. We just need to…

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STFC-RAL-CR03-RAL-R61-2.01: basically find purification techniques that would work with a certain scintillator, or, if you are… if you're, for example, using electrostatic chamber different metallurgy, you need to find

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STFC-RAL-CR03-RAL-R61-2.01: at,

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STFC-RAL-CR03-RAL-R61-2.01: maybe need to make them from, electrophone Harper as an example. I mean, we need to, like, you know.

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STFC-RAL-CR03-RAL-R61-2.01: I think it's possible, though. Yes. It's not realistic. And you mentioned about commercial.

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STFC-RAL-CR03-RAL-R61-2.01: devices.

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STFC-RAL-CR03-RAL-R61-2.01: Do you know why they are better, and what their application is?

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STFC-RAL-CR03-RAL-R61-2.01: Except that they're expensive, why we can't use… Oh, so sorry, which, which one? In the first part, you mentioned about the commercial… Oh, it's just that the commercial ones are… it's only… they can only measure… Only the measure. They can measure, yeah, it's just not good enough for, giving… they don't give us enough information. Okay. They only give… so, they only… the commercials are only given

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STFC-RAL-CR03-RAL-R61-2.01: information about the top of the chain, and information on the bottom of the chain. Right. They don't give information of the middle of the chain. Actually, for diabetic, is the most important part. Yes. Do you know commercially what they are used for?

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STFC-RAL-CR03-RAL-R61-2.01: Oh, sorry. So,

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STFC-RAL-CR03-RAL-R61-2.01: Oh, one of them is ICPM. Is that what you're talking about ICPMS, one of them is a mass spectroscopy. Yes. And the other one is XIA, alpha extract.

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STFC-RAL-CR03-RAL-R61-2.01: It's just a brief chamber, which is basically, has honored and model, and measuring, basically, the ionization of everybody's world. Did that answer your question? Yeah, yeah, that's… yeah. One last question on the picture, one slide back.

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STFC-RAL-CR03-RAL-R61-2.01: You could use the pointer. Okay.

347
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STFC-RAL-CR03-RAL-R61-2.01: Oh, yeah.

348
00:59:01.340 --> 00:59:20.470
STFC-RAL-CR03-RAL-R61-2.01: It doesn't work. Yeah, I was wondering whether this is an underground picture? Yes. And, why the walls are white. Oh, yes, this is, this is basically, the Harper paint. It is underground.

349
00:59:20.570 --> 00:59:26.470
STFC-RAL-CR03-RAL-R61-2.01: It's a type of paint we put in in order to, reduce further ingress.

350
00:59:26.840 --> 00:59:46.260
STFC-RAL-CR03-RAL-R61-2.01: The whole, whole area. Like, the whole snow lamp is covered with this. It's white. Okay, it also looks very bright. Yes, it looks… I mean, yeah, it is, it is, it is, it does reflect. It does reflect. If you're next to it, then I recollect.

351
00:59:46.560 --> 00:59:47.550
STFC-RAL-CR03-RAL-R61-2.01: Yes.

352
00:59:48.170 --> 00:59:53.930
STFC-RAL-CR03-RAL-R61-2.01: And, despite of that, we set up 120 bands for every two weeks. I don't know how it was.

353
00:59:54.240 --> 00:59:56.259
STFC-RAL-CR03-RAL-R61-2.01: Maybe I have that.

354
00:59:57.530 --> 00:59:58.460
STFC-RAL-CR03-RAL-R61-2.01: Okay.

355
00:59:58.860 --> 00:59:59.770
STFC-RAL-CR03-RAL-R61-2.01: Is that…

356
00:59:59.810 --> 01:00:19.159
STFC-RAL-CR03-RAL-R61-2.01: from Raiden Group, I heard from Sammy, you mentioned. Sorry. I've already asked. Maybe you can talk. I don't do anything on Raiden, by the way. I'm just in that building. Oh, okay. You don't have a rhythm, right? No, I don't work on Raiden.

357
01:00:19.270 --> 01:00:27.080
STFC-RAL-CR03-RAL-R61-2.01: Okay, on that note, let's close the seminar here, and thanks again, everyone, for doubling.

358
01:00:30.460 --> 01:00:34.460
STFC-RAL-CR03-RAL-R61-2.01: Okay, fine.