STFC-RAL-CR03 R61: You are
STFC-RAL-CR03 R61: agree to give you time now, I would like to take a few moments to introduce our speaker today.
STFC-RAL-CR03 R61: He's 1 of our own internal, who recently completed 25 years
STFC-RAL-CR03 R61: at Ppd. And last week treated us with all the things, remind us a wonderful story of his adventures. If you missed it.
STFC-RAL-CR03 R61: Too bad. Any case at present. He's the group leader of Lscd group at Ppd. And project leader of one of the major protectors of Lscd. Called Rich, which stands for imagination, for detector, which is crucial for particle identification at Lhcd.
STFC-RAL-CR03 R61: When you look at his career it feels like he has been playing with imagining detector toys from his childhood.
STFC-RAL-CR03 R61: His carrier spends everything from medical imagining to managing major particle physics projects.
STFC-RAL-CR03 R61: He started with a Phd. At University College, London, in 1993,
STFC-RAL-CR03 R61: on medical uses of microstric test chambers, and moved on
STFC-RAL-CR03 R61: to a meditary fellowship in in visa guarantee
STFC-RAL-CR03 R61: gathered in both medicine and Cms.
STFC-RAL-CR03 R61: And then he returned to Eql to work on X-ray, imagining in medical Physics department.
STFC-RAL-CR03 R61: Since 2,000 he has been a trial becoming a pillar of Lsu experiment from aligning the risk detector to leading its operations.
STFC-RAL-CR03 R61: designing its control systems and eventually becoming the rich project leader.
STFC-RAL-CR03 R61: And, as I understand it, we also took a detour to manage June Uk. From 2018 to 2021,
STFC-RAL-CR03 R61: and since 2021, he's the Lsd group leader.
STFC-RAL-CR03 R61: So without further ado, I can keep on going. It's a long list of his achievements. But without further ado, please join me in welcoming and talking.
STFC-RAL-CR03 R61: Well, thank you for giving me another opportunity to talk about the electric here, and I honestly believe these are the best detectors ever made in terms of performance. So.
STFC-RAL-CR03 R61: as I said before, so the idea is to go through what happened in the past. Be a little bit of entertainment, though, and and just remember. So for the members of the audience that maybe not very familiar with risk detectors. The idea that you go to radiator. Usually a gas, a parcel goes through.
STFC-RAL-CR03 R61: Then it's a zone of radiation. Then it's photons. And then we detect these. And the important factor is that the angle. Radiation is governed by the fractive index
STFC-RAL-CR03 R61: for it.
STFC-RAL-CR03 R61: That means that if you measure the the angle and you know the effective index, you can measure the speed of the particle independently of the momentum. Then you combine information with momentum from the tracker, and you can extract the mass and mass is what tells you what type of particle you got, and mainly the difference is, you can differentiate the pattern. You can tell about volumes from cadence, from
STFC-RAL-CR03 R61: the problem and the 2 ways of focusing one is called proximity focus. You can see the other one requires. It is usually done for a solid, like an aerosol or pieces liquid, the small amount of liquid, and the other one is used for a gas radiator, where you go to a spherical mirror, or something similar in order to to create a ring image. And the ring imaging is what gives you the acronym which is ring imaging triangle detectors. That's the rich part.
STFC-RAL-CR03 R61: So come to Lx. 3.
STFC-RAL-CR03 R61: And and this is this is a picture of Lhcv, it's a forward spectrometer, because the V particles that we study are generally emitted at very low angles. So we we instrumented, if you like, around the V pipe, and we only do
STFC-RAL-CR03 R61: 1 1 arm. So we lose. We lose half the interactions, if you like, going the other way. So we start from interaction going. It's at one end of the experiment. And then we've got the tracker detector of the fellow, and we go through each one the magnet. More tracking stations, which group is a much bigger brother, of which one and the color limits so so that the typical kinds of physics experiment. But the fact that we are the spectrometer and everything goes
STFC-RAL-CR03 R61: in order. In fact, you got the space to put to put the various vectors in there.
STFC-RAL-CR03 R61: and this is what the original detectors look like, and I'll explain why I say original. So this is each one see from the side. So it has a vertical arrangement, and you see, the photons get emitted in the radiator. They get reflected in a set of spherical mirrors again in a set of flat mirrors. And now into the photon detectors.
STFC-RAL-CR03 R61: The flappers are there to limit the length of the radiator a little bit well, not limited, but stick everything within the same Z, and allow you to place the photo detectors outside the acceptance of the of the experiment.
STFC-RAL-CR03 R61: And what you see in the original version, of which one is that you got 2 radiators. You got the gas radiator, which is C. 4 x. 10. And then there was an aero radiator that was supposed to differentiate the flow of momentum between tayons and and protons.
STFC-RAL-CR03 R61: and then which 2 is very similar, only it's horizontal. So this is not from the top.
STFC-RAL-CR03 R61: and you get again the same. The same arrangements with the space or the platiners and the bottom detectors on the side.
STFC-RAL-CR03 R61: The only difference is that reach 2 is using Cfo as a radiator. So it works at high momentum.
STFC-RAL-CR03 R61: and so we don't instrument the full acceptance of the experiment. We all go all the way up to 120 meteorads in the horizontal plane. And this is because most of the high momentum tracks tend to be closer to the v. 5. So if you look at high momentum at large angles. You don't get many things. So this is an optimization that we love.
STFC-RAL-CR03 R61: And every school was designed and built. And this is this is a very early version of this group, if you like. This is what it looked like when the materials arrived at the company. This is not on site. This is at the company was made.
STFC-RAL-CR03 R61: and this is what bridge to look like at installation time in 2,005. This is down at the Lhc peak you can see bridge to fly. This is about 30 tons in total about 20 tons of magnetic fielding that you can see in green on both sides, and of the order of 10 tons of aluminium in the middle. This was an extremely successful project. Bridge 2 has been sitting there since 2,005. So it's been 20 years now.
STFC-RAL-CR03 R61: Sorry. Do you still have Arizel? Or no, no, I'll count it up. You go through it.
STFC-RAL-CR03 R61: That was English. And the other thing that I need to tell you about, there are the problem detectors that we use at design, which we call the hybrid.
STFC-RAL-CR03 R61: Not only that close, it was a pixel. Is that close? And just to give you an idea of the complexity of the whole thing. So the
STFC-RAL-CR03 R61: these devices were supposed to have a silicon
STFC-RAL-CR03 R61: pixel sensor inside the vibe with a with a photocopal in order to have a large area coverage, but also be sensitive in in position. Show you how this is done.
STFC-RAL-CR03 R61: So you start with the detector chip and the readout electronics that were made from different companies. You take them to another company and you do the bomb building
STFC-RAL-CR03 R61: and you get the carrier, which is the same carrier as a painting processor, I believe, which you then need to send somewhere else to braze and and block, and then you bring the whole thing together, and you put it all together, and that gives you your arm. This is where you. You will detect your electrons.
STFC-RAL-CR03 R61: and then we take the anode, and we give it to another company where they they put it, and then they put the porch window that we have there on the inside of the porch window. We deposit the photo packet.
STFC-RAL-CR03 R61: And you want to. You got the the whole the whole. And the way it works
STFC-RAL-CR03 R61: is that you get a photo
STFC-RAL-CR03 R61: that gets converted into an electron photoelectron after photocathed on the inside of the course window. And then that gets accelerated towards your silicon sensor with a voltage of up to 20 kilovolts. So in principle, what you get hitting the silicon pixel sensor is a 20 Kb, electron
STFC-RAL-CR03 R61: which you can then detect. And you you've got the encapsulated without electronics, you know, with inside the queue. And then you get the signal sound already digitized, serialized, and and everything else.
STFC-RAL-CR03 R61: And this is what it looks like when you start them all together. We have the 488 t's, in both which one and which 2 in total, almost 500.
STFC-RAL-CR03 R61: So that's the background. And then in 2,007,
STFC-RAL-CR03 R61: the Hds that were installed in reach, one sorry reach 2. Because we started with reach. 2 were switched on for the 1st time.
STFC-RAL-CR03 R61: and this is fun we saw.
STFC-RAL-CR03 R61: Oh, it wasn't great.
STFC-RAL-CR03 R61: I'll explain what we see. So the 1st thing we saw is that some columns are fine, but some other columns have. HD. That showed extreme activity, although there was no light.
STFC-RAL-CR03 R61: and if you were to try and switch on the high voltage, it would trip with the voltages that- that we have
STFC-RAL-CR03 R61: and
STFC-RAL-CR03 R61: but it turned out to be after a lot of investigation. This was the biggest issue that we had in the exist.
STFC-RAL-CR03 R61: There was out gassing into the vacuum of the tube. So here we look.
STFC-RAL-CR03 R61: So when you get an electron coming through, what happens is you've got a certain probability of actually hitting one of the gas molecules that are inside the tube and then ionizing it, and of course the ion then will drift towards the Herocouple, and it will generate more electrons, and that will do the same thing, and of course the arrangement of the electric field. Besides that, the ions will just go through the middle, and this is where you get most of the activity right in the middle of the tube.
STFC-RAL-CR03 R61: So, in effect, what we have is a tube that is glowing like any of light.
STFC-RAL-CR03 R61: and these things were unusable.
STFC-RAL-CR03 R61: So we had to spend a lot of time trying to understand part of the problem, the solution that was found in the end. Well, the company never accepted liability, maybe that it was their fault, although that was the only possible way, and of course we didn't want to push too hard because
STFC-RAL-CR03 R61: they might have said fine. We're not interested anymore, right? And then we'll never expect that.
STFC-RAL-CR03 R61: So the arrangement that was found in the end was that
STFC-RAL-CR03 R61: they would take both your spark.
STFC-RAL-CR03 R61: they will repair them, and they will give them back to us at half the price of the original tubes.
STFC-RAL-CR03 R61: So we ended up replacing, probably around half the tubes that we have in total. And now what does it mean? Repair repair meant you open up the tube.
STFC-RAL-CR03 R61: You keep the amount, and you make a new queue.
STFC-RAL-CR03 R61: And of course that meant every time we're making a tube we have to take it out, and of course, the electronic. So always a little bit worried so that the tubes and come back after repairs. We've always had a high one.
STFC-RAL-CR03 R61: But then everything within groups.
STFC-RAL-CR03 R61: And so we have this campaign that lasted 10 years for almost. So we're just repairing cubes for new ones at the product.
STFC-RAL-CR03 R61: anyway. So still, in 2010 we got our 1st performance.
STFC-RAL-CR03 R61: and it didn't look too bad in in some ways. So these were the standard lots that we normally saw of the obviously efficiency, and at the bottom is id.
STFC-RAL-CR03 R61: If you look at the the efficiency has always been great. You know, about 90%, 95%. But
STFC-RAL-CR03 R61: take a look at the Miss Id. It's about 10% close to 20%.
STFC-RAL-CR03 R61: You'll see how this improves over time.
STFC-RAL-CR03 R61: But we were extremely happy to get down to the of the experiments for the 1st time.
STFC-RAL-CR03 R61: What you will see is that almost all of the slides are slides that were taken from the summaries that were given during the time. So this is for
STFC-RAL-CR03 R61: and in October 2010 we both. We published our 1st resolution, gloves with trips to being at sort of 0 point 7 Monte Carlo expectations, or something very similar. We're extremely happy to do this.
STFC-RAL-CR03 R61: which one
STFC-RAL-CR03 R61: never managed to achieve Monte Carlo resolutions. We are now realizing that part of it is simply on how we compare the data and the Monte Carlo and and potentially done better. But there were potentially other little things the magnetic field in the area which one is significant. It distorts the images on the electrons fly through the cube, and we have to calibrate for that.
STFC-RAL-CR03 R61: And we think the calibration was not, was never as good as as having no magnetic field, and and I'll explain later in the day what was done.
STFC-RAL-CR03 R61: It's saying dying.
STFC-RAL-CR03 R61: We have to worry about pixels.
STFC-RAL-CR03 R61: For some reason the very early versions of pixels in Lxb. And across others in Cms were dying.
STFC-RAL-CR03 R61: and it was not clear whether this was going to be a big problem or not. Problem at all. Some of our other side effects in LCD had significant issues. So the pixels, sorry, maybe explain. The pixels are the elements that create the light that they use to transmit data down, either.
STFC-RAL-CR03 R61: So they're driven by
STFC-RAL-CR03 R61: other tips. But these were the ones that actually they're the laser that you use in order to transmit later. So if you use that, then you lose communication. If you have no data coming out for us, we would have one of these spare HP, and HP is a thousand or so.
STFC-RAL-CR03 R61: So losing out these is is something significant.
STFC-RAL-CR03 R61: So we have to start worrying about which ones to change which ones not to. Should we have a campaign where we start changing loads plan, we decided against it, and that would be a good idea, because after that no more pixels actually died.
STFC-RAL-CR03 R61: And then the next thing that we discovered was that when the Mhc. Was injecting we could see a lot of activity on objectors.
STFC-RAL-CR03 R61: and
STFC-RAL-CR03 R61: these are one of the things that are perfectly predictable. But no one has ever talked about, so you never expect it. What is going on the
STFC-RAL-CR03 R61: bill. 2 for the Lxc. Actually comes in to the Lxc from the Sps about 300 meters
STFC-RAL-CR03 R61: downstream neuron side of the electricity experiment.
STFC-RAL-CR03 R61: So when they're coming in, they have a always a little bit of losses that get picked up by the collimators that they've got there, which then spray particles onto the electricity experiment.
STFC-RAL-CR03 R61: and that under normal conditions is fine.
STFC-RAL-CR03 R61: But every now and then and in the run, 1, 2, especially during run one, I think, happened probably 3 times.
STFC-RAL-CR03 R61: The kick amount fails to kick the me properly, so you may get up to potentially 288 nominal bounces. But get the collimators, and you can get up to
STFC-RAL-CR03 R61: 10 to the 6 Newtons per per centimeter, or something like that coming down through led
STFC-RAL-CR03 R61: with photon detectors producing strength of light on the quotes fingers.
STFC-RAL-CR03 R61: So the decision was then taken that we had to switch off the high voltage to make sure that we don't damage our code infectors.
STFC-RAL-CR03 R61: And
STFC-RAL-CR03 R61: around the high voltage after injection only turns out that if you're ramping 20 kilovolts next to electronics at 5 volts. They don't like it at all.
STFC-RAL-CR03 R61: So the solution was, you shoot everything off.
STFC-RAL-CR03 R61: You wait until ejection has finished, and then we're going to run. And then you switch on the high voltage
STFC-RAL-CR03 R61: slowly, because you cannot go to 20 kilovolts very quickly, and then you wait 5 min.
STFC-RAL-CR03 R61: Originally, just 10 potentially have to be that 5, because we had 3 months to follow the process a little bit faster for everything to stabilize. And then we switch on the local things.
STFC-RAL-CR03 R61: So this was eventually implemented in our fine state machine that we built, and it was all working pretty well.
STFC-RAL-CR03 R61: And once things got going we can realize that we have more data than expected.
STFC-RAL-CR03 R61: Somehow there was more line coming out of the newspapers than we had calculated. So
STFC-RAL-CR03 R61: the- the You know 488 fibers. Both expected to go into what we used to call the detail level one boards, and there they would be converted into Ethernet packet data that would be fed into the farm.
STFC-RAL-CR03 R61: and the bandwidth was just not there to to cover everything. We couldn't go.
STFC-RAL-CR03 R61: And and although we have made almost twice as many boards as we thought we're gonna need.
STFC-RAL-CR03 R61: we still getting so all the forwarding we just couldn't cope with the data. But we call about the. So we saying, we cannot take any more data because we cannot cope. And that meant the time, the time for the experiment.
STFC-RAL-CR03 R61: So it became obvious that the reason this is happening is because Cfo is also a simulator.
STFC-RAL-CR03 R61: And this is another thing that we could predict very easily, but no one thought of
STFC-RAL-CR03 R61: second right. So we have the second of life. But we also have simulation live.
STFC-RAL-CR03 R61: and the simulation light, it turns out was a part of this plentiful leather term of life.
STFC-RAL-CR03 R61: And and yeah, that was what is the causing the problem. And we're going to verify this, because in 2,009, very early on
STFC-RAL-CR03 R61: we had. So for both fix detectors, what you do is you? You fill them up with Co. 2, and then fill them up with a chlorocarbon, because you can easily separate Co. 2 from the pro carbon while you can manage them there. It's almost impossible to separate.
STFC-RAL-CR03 R61: so we'd always start the the year with school started the 1st time in 2,009, and then Stage 4, in in which one we just filled out with with Co. 2, and you can see in in 2,009, when we had about 30% of Co. 2.
STFC-RAL-CR03 R61: The this is on the left, because it's which one and this is the occupancy of the various sample detectors, and the the reason they go up and down is because in the middle of each of these columns you've got high occupancy in the middle of the of the of the acceptance.
STFC-RAL-CR03 R61: but you can see the difference in the background in reach 2 between having plenty of Co. 2 and having very little Co. 2.
STFC-RAL-CR03 R61: So we were convinced by some doing some experimental measurements as well, that, including Co. 2 in cf. 4 would be very helpful in removing scintillation, because the Cfo molecule could
STFC-RAL-CR03 R61: lose some of its energy through collisions with a Co. 2 molecule before it had a chance to simulate.
STFC-RAL-CR03 R61: And this is what we ended up doing. And this is what I said today. So we calculated that we needed about
STFC-RAL-CR03 R61: 8, 8 to 10% of Co 2 would be would be fine. And the nice thing about Co. 2 is that that's the same attractive index.
STFC-RAL-CR03 R61: If the dispersion is different, how we are operating the changes with with wavelength is a little bit different.
STFC-RAL-CR03 R61: And this is why we don't use Co 2, and we use Cfo, because, because it's more flat. So it's easier you get a better resolution. But the solution was then to to do this.
STFC-RAL-CR03 R61: So you saw it in, both problem was rich, one and 2. So in the 2 different gases, neither so much. No rich 2 was the main problem, which one was not such a problem. So the C. 4 F. 10 doesn't seem like, okay. And that's why you can see that. I mean it was there. But the rich one was not a problem
STFC-RAL-CR03 R61: which one was not broken.
STFC-RAL-CR03 R61: But you still put have 30%. Co 2. No, no, we didn't. Only 2. This is only 42,
STFC-RAL-CR03 R61: the 30% booked.
STFC-RAL-CR03 R61: This is which one this bit, and it's the same. We didn't change anything.
STFC-RAL-CR03 R61: or you can see when you do not get any Co. 2, you get all of this background light, and then it disappears.
STFC-RAL-CR03 R61: Okay, thanks. Misunderstood your answers. Yeah.
STFC-RAL-CR03 R61: And at the same time we're starting looking at the performance of the auto.
STFC-RAL-CR03 R61: And and this is sort of what we would see. It turned out that everything wasn't performing particularly well.
STFC-RAL-CR03 R61: So this is what the performance looked like. The resolution was kind of terrible well, not terrible, but worse than one expected. The number of photos that we're getting was smaller, and they were really completely drowned in the
STFC-RAL-CR03 R61: number of problems we're getting from the chord side.
STFC-RAL-CR03 R61: much, much bigger rings, but was extremely difficult to define. But we did. When we had at some point the test. We had only in the very early into it, I think, 2011. We did the test, for
STFC-RAL-CR03 R61: we run the experiment a little bit before changing from Co. 2 to support them, and we noticed that there was a big improvement in the resolution. So what was decided was that in order to be able to use the error in some way or another. We're going to build a box
STFC-RAL-CR03 R61: so that the support then will go resigned. Yeah, so actually, it is very likely.
STFC-RAL-CR03 R61: because sales is a fine material. It's like a sponge with very, very fine structure. It's possible that the
STFC-RAL-CR03 R61: Cfo. Was actually being absorbed in more than what you think. I was acting a little bit like a in some ways. So if you were to, if you were to put a file in in, you know, in a c 4, 10 environment. Any way, you could see that it does absorb more c. 4, 10 than the volume of the file itself
STFC-RAL-CR03 R61: so potentially the hope
STFC-RAL-CR03 R61: it was super time compensation happening inside the hotel as well in in some sort of liquid form, or something which we're not sure.
STFC-RAL-CR03 R61: So the decision was made to to build the box in order to avoid this. So all of these things were sort of okay. It's maybe going this way and then- and then this happened.
STFC-RAL-CR03 R61: What is this this?
STFC-RAL-CR03 R61: But suddenly, in the middle of around
STFC-RAL-CR03 R61: our Hvd. Is starting to emit light.
STFC-RAL-CR03 R61: you can see that there's the activity here. And what you see in this plot
STFC-RAL-CR03 R61: is the silicon bias current of the silicon sensor. So this tells you how much current you get through your your silicon.
STFC-RAL-CR03 R61: and you can see it's going through the roof, and it's fluctuating enormously. You would expect this to just be a straight line right?
STFC-RAL-CR03 R61: And then you can see how it goes up and down. It wasn't too close to the limit, so it wasn't damaging the sensor, but it was really showing us that there was a lot of activity in these things.
STFC-RAL-CR03 R61: and we didn't really know what it was.
STFC-RAL-CR03 R61: There was nothing significant on the high voltage side. So it wasn't sparking or anything like that.
STFC-RAL-CR03 R61: And we dealt with the corona effect.
STFC-RAL-CR03 R61: So what was happening is that somehow
STFC-RAL-CR03 R61: electrons would go from the photocapfold well, from the capital that was at minus 20 kilovolts to the magnetic field which is of the other side of the captain
STFC-RAL-CR03 R61: point with enough energy to produce life.
STFC-RAL-CR03 R61: but without actually getting any actual sparks or anything like this.
STFC-RAL-CR03 R61: and of course that would kill our detector, and it was ready. It started on one Sv.
STFC-RAL-CR03 R61: And then after a while, it started going, moving along.
STFC-RAL-CR03 R61: So how will happen is that as soon as you drop the beam, there will be none of this. So clearly. There was some ionization going on with the
STFC-RAL-CR03 R61: the beam coming on, and then but when the beam will come.
STFC-RAL-CR03 R61: Once it started, even the top would have been one. You get to take the half of it down.
STFC-RAL-CR03 R61: and then please stop again.
STFC-RAL-CR03 R61: and we were scared. I mean, that was really really scary, because we had no idea how to do this.
STFC-RAL-CR03 R61: And the solution. This is a little bit of what? How it was actually going on.
STFC-RAL-CR03 R61: The solution eventually was.
STFC-RAL-CR03 R61: Co 2. Again.
STFC-RAL-CR03 R61: we used to get nitrogen in in the volume of the photo detectors, because nitrogen has a 1 behind the constant. So you expect less sparkling. If there was anything about. So in that sense, Co. 2 is a less less good. You know, it's not a good gas. But again.
STFC-RAL-CR03 R61: Co, 2 can grab electrons that are moving around in in funny ways.
STFC-RAL-CR03 R61: And by adding Co. 2 into the electron closer. This phenomenon has helped.
STFC-RAL-CR03 R61: And it really really saved the day.
STFC-RAL-CR03 R61: We we did some testing to understand everything. And it did. It did really work. So we changed from managing to Co. 2.
STFC-RAL-CR03 R61: But then we're a little bit scared. So the original
STFC-RAL-CR03 R61: high voltage of these devices is supposed to be 20 kilovolts.
STFC-RAL-CR03 R61: because we've had some issues with the power supplies we reduced up to 18 kilovolts.
STFC-RAL-CR03 R61: and after that situation we give it to 16 kilovolts.
STFC-RAL-CR03 R61: because once that that started it was difficult to solve it.
STFC-RAL-CR03 R61: We went after a ticket. It was very fine that wasn't happening, but then we're scared to leave it there. So it went back to 16,
STFC-RAL-CR03 R61: and as a project leader one in 2018, I said, come on, let's take it back to 18, you know, you could get the 2 or 3% improvement in efficiency by having a high voltage. People said, no, so
STFC-RAL-CR03 R61: we operate at 16, kilowatt after that.
STFC-RAL-CR03 R61: And then there was a high university test that we did in in Lxb. Just to see how things were going to work.
STFC-RAL-CR03 R61: We're generally quite happy with the whole thing, but it's always a push for more.
STFC-RAL-CR03 R61: but saves us in the end. Actually, it was. The other traffic was throttling before. It's too.
STFC-RAL-CR03 R61: Once we put the the the Co. 2 in to stop the simulation, and once we
STFC-RAL-CR03 R61: use a few of these spare boards that that will prototypes and and fly as many as we have reached the point. But one of the other sub detectors, the other tracker, which throttle before us.
STFC-RAL-CR03 R61: and you only need a tiny little magic.
STFC-RAL-CR03 R61: and because scrolling works in the sense that once you hit the the limit as soon as you go a little bit about. Just stop taking data. You cannot learn anything.
STFC-RAL-CR03 R61: And that was what translated.
STFC-RAL-CR03 R61: And in June 2011, for the 1st time. So you want me to
STFC-RAL-CR03 R61: figure out how many photons we're actually getting. Now, this is this has been a huge problem for the electricity, because.
STFC-RAL-CR03 R61: you know, a sort of a typical event will have a hundred 50 trucks, and they're overlapping and trying to figure out how many problems you open. Some individual track is extremely difficult.
STFC-RAL-CR03 R61: So we try to develop a procedure to to do that. And we ended up with something that said that we're getting about 3 quarters of the number of problems that we have.
STFC-RAL-CR03 R61: We know now that this process doesn't help you really
STFC-RAL-CR03 R61: anything. It's difficult to compare with what you would expect from. It's extremely difficult.
STFC-RAL-CR03 R61: And and that has been the case sort of more or less since then, but being able to get a number can be quite useful, and you will see a little bit later.
STFC-RAL-CR03 R61: So one of the.
STFC-RAL-CR03 R61: you know. Interesting story. So this is one of the Uk level one boards that was struggling.
STFC-RAL-CR03 R61: So what would happen is that the front here you've got one to 3 inputs. You can get up to 12 fibers per input, you can have potentially up to 36 coming into one of these boards. Then these, from that processing, everything gets back into the central Fpga, and it comes out the data goes to the farm to 4 gigabit per second links.
STFC-RAL-CR03 R61: and
STFC-RAL-CR03 R61: it was on this situation. So we have to. As a operations coordinator. On my side. I had to persuade somebody else back in the Uk. That it was their problem and not my problem. Fortunately I had the data to show, but the theoretical
STFC-RAL-CR03 R61: way that this board should work, you know, with 4 times 2.5 and putting it down wasn't actually working.
STFC-RAL-CR03 R61: that it wasn't. It didn't manage to do the 4 times 2.5 gigabit key at all.
STFC-RAL-CR03 R61: So once I have the data to- to show them. They went back. They did some calculations, they realized they had some inefficiencies in the framework which they fixed.
STFC-RAL-CR03 R61: and once the board started working at the level that we wanted, that was really when we solved the throthy problem once and involved.
STFC-RAL-CR03 R61: And and that was really good.
STFC-RAL-CR03 R61: But it's a when you're concerned. It's always hard 1st with somebody that's not concerned. But it's their problem and not your problem.
STFC-RAL-CR03 R61: So this is this is what we have.
STFC-RAL-CR03 R61: we we have put 16 boards in in which to start with. Once you get down to 13 boards after the Co. 2 and 10 boards and 11. And this is the whole story. But once that presented, then all of the throttling issues were gone. We still made a few, a new, a couple of prototypes, more boards, because electricity wants to go to higher.
STFC-RAL-CR03 R61: Highly, and we were very close to the limit, but we never had to use them, because the architecture for us.
STFC-RAL-CR03 R61: And this was from yes, the 2011. How you can prove that your pi algorithms can cope really, really well with increased background.
STFC-RAL-CR03 R61: You forget the laser that you use for the calibration of the photo detect on while doing tape checking.
STFC-RAL-CR03 R61: And, interestingly enough, you can see the the distributions in in red. Here is the reference. And in black is what we're getting. So we're getting about 20% more photos.
STFC-RAL-CR03 R61: And the data manager who's looking at this thing didn't notice anything unusual, interestingly enough, but the situation.
STFC-RAL-CR03 R61: We've had more light into the detector. And so we're causing daytime. We are like this for 20 min until I have to run down the street of the suite of the laser, which was not we want to control
STFC-RAL-CR03 R61: and but to put down, and eventually.
STFC-RAL-CR03 R61: December 2011, we actually showed some of the really really good performance. So each 1 1.6 million, we were expecting more, something like 1.5 and reach to 0 point 6 million, which is pretty bang on Monte Carlo. And this is since then the performance that we typically show so have a look at this area over here.
STFC-RAL-CR03 R61: Let's say, between 10 and 50 TV, right? You got
STFC-RAL-CR03 R61: channel notification. That's about 90%
STFC-RAL-CR03 R61: getting really close to 100% at about 2030 Tp and Miss Id, that comes down to below 5%.
STFC-RAL-CR03 R61: And- and you know, and you can actually do all the way from 2 to a hundred. So this has been our sort of benchmark ever ever since.
STFC-RAL-CR03 R61: One of the improvement that we had to do, and that was possibly one of the things that one hadn't expected to happen is that we discovered early on.
STFC-RAL-CR03 R61: But the electrostatics within these Leds
STFC-RAL-CR03 R61: we're not as stable as one would expect it.
STFC-RAL-CR03 R61: So what you see here in these circles on this side, that's that circle over here is the photocap image on the result team, but that we have.
STFC-RAL-CR03 R61: And
STFC-RAL-CR03 R61: then what you can do if you, it's a sort of alignment, right? That you need to do is you need to figure out where exactly is the center of that, because you may not be completely in the center of the city.
STFC-RAL-CR03 R61: and then you can say, What are the 40 min, and we're expecting to do that. But we're probably gonna do that once per, and that would be for the last time.
STFC-RAL-CR03 R61: It turns out that that is not the case.
STFC-RAL-CR03 R61: Part in it. Once you once you do the processing and you find the center, and then you split your data and time that center moves
STFC-RAL-CR03 R61: and you can see wandering off. So in these lines, what you're seeing is different fields that lasted, you know, 1216 h, and in blue is early in yellow. It's late.
STFC-RAL-CR03 R61: and the the squares represent a pixel
STFC-RAL-CR03 R61: on on the circumstances. So some of them move. You know this one. It moves just a little bit, but stay within the same pixel. So it doesn't really do anything. But, you know, look at some of the other ones, I mean, they really wander off.
STFC-RAL-CR03 R61: Now, this is a this is kind of strange right? You would think truly cannot go outside the
STFC-RAL-CR03 R61: the problem that we kind of had. In order to understand this a bit better was that
STFC-RAL-CR03 R61: after 16 or 20 h you could switch off, because then, let's see, within Zeppe again.
STFC-RAL-CR03 R61: so you would start over again, and sometimes when you start over, you start with the same place, and sometimes you start at a different place, but it was always difficult to know what would actually happen to these kids after a very long period of time, whether they eventually
STFC-RAL-CR03 R61: stabilize something? Was it the heating up because you switch everything off and you switch everything back on is some charging that happening inside the HD. That causes the electrostatics to change. We never figured it out but doing this and then doing that calibration in real time every hour allow us to get the the performance that we need to get out of the out of this.
STFC-RAL-CR03 R61: because if you did calculate for that, you couldn't get to the stuff particular performance that we have, which was really good. So you never really understood it. We never really understood. It's not a huge trip. I mean, it's the pixel size. Yeah. And the the thing. Is that so? Then what we also thought that was possibly happening is that
STFC-RAL-CR03 R61: if the whole thing is moving, I mean, you've got a you've got a photograph of that size, and that the electrostatics bring everything down to a smaller size, but potentially that radius is also
STFC-RAL-CR03 R61: increasing and decreasing as well, and that is an effect that we never managed to calculate, so that potentially was limited a little bit of resolution within, in which 2, where you put a very huge. A very long live around the the buttons go 4 meters before they actually hit the button effect, because the pixel size there is tiny. So if you get this a little bit wrong, it doesn't matter, but which one is much smaller. And we used to think that that was part of the reason we get to Monte Carlo resolution.
STFC-RAL-CR03 R61: although now we're discovering a a few other things in the process.
STFC-RAL-CR03 R61: And then, in December 2011, we opened up the problem we have with which which one is which one you could only open up at the end of the year, because it was inaccessible
STFC-RAL-CR03 R61: the way the way it was constructed. You needed a week to get things out. And then, once we did that, actually, this is From- from Youtube, we you see these little spots.
STFC-RAL-CR03 R61: This is what was causing us the corona.
STFC-RAL-CR03 R61: So it turns out that we have
STFC-RAL-CR03 R61: probably something like micro discharges between. So this is the this is the captain on the outside of this. That would be a magnetic field, and then on the inside of this, that would be the the the would be sitting in here.
STFC-RAL-CR03 R61: and so there were small discharges at the level where the Catholics to the custom
STFC-RAL-CR03 R61: in some way or another.
STFC-RAL-CR03 R61: and what we then did was we cleaned everything, and then we centered everything, make sure that nothing was bouncing anything else, and that potentially prove things
STFC-RAL-CR03 R61: so that was the summer that was presented at the end of of this year, and we're really getting happy with the performance that that we have.
STFC-RAL-CR03 R61: And in the break what we did. We actually included them, the new boxes for the architect. And let's see how that was going to work. You can see you can see the boxes so bellows on this side. This is the box on this
STFC-RAL-CR03 R61: fine. You would think that by now, you know, the video has been running for more than a year we understood everything.
STFC-RAL-CR03 R61: Then other great things happen.
STFC-RAL-CR03 R61: Look at, look at these, so let's see, this is the before and the after. So what will happen is
STFC-RAL-CR03 R61: the detector will be running. Then you get an error. You press the reset button, reconfigure the front end, electronics start running again, and then we would see
STFC-RAL-CR03 R61: but the number of hits that you get on specific. You see these at the bottom we don't.
STFC-RAL-CR03 R61: I'll
STFC-RAL-CR03 R61: there wasn't any reason why this would happen right? I mean, this is just like, so somehow, we're missing buttons
STFC-RAL-CR03 R61: from sound made to it.
STFC-RAL-CR03 R61: and we couldn't really understand what what was going on. So we had to consult the experts. What actually happens. As you said.
STFC-RAL-CR03 R61: As we said, it turns out that you're doing calibration. So because there was a particular duck
STFC-RAL-CR03 R61: that will give you a voltage that we use at a threshold, but with sensitive temperature. So when you start the vector it will calibrate a certain value.
STFC-RAL-CR03 R61: But once a detector had been known for a while, and the temperature will increase when you send the reset and reconfigure. It would recalibrate, but now at a different package.
STFC-RAL-CR03 R61: But somehow this new calibration was actually causing the loss of audits which was not particularly good.
STFC-RAL-CR03 R61: So oh! And this actually started happening later on, because it would only happen at the 3 year at the very high ticket.
STFC-RAL-CR03 R61: So Lncv, are the maximum level level 0 to gauge of one Megahertz.
STFC-RAL-CR03 R61: Alright. So if you were on the detector up to 500 kilohertz, that is the rate that you're sending data from the contents
STFC-RAL-CR03 R61: to the back end. Nothing so.
STFC-RAL-CR03 R61: But the closer you're getting to one, Megahertz, you would see this effect becoming more and more appreciable.
STFC-RAL-CR03 R61: So we
STFC-RAL-CR03 R61: we talk to the people that have made the electronics for the going on and things like that. So just to point out one of the things that we always have is the ability to plus the 400 pixels of the data
STFC-RAL-CR03 R61: through a test out. So what will happen is that if you are.
STFC-RAL-CR03 R61: if you're running like this, you would get for every one of these events, you would actually get 4 kids very easily.
STFC-RAL-CR03 R61: And let's say that you, on top of the 4 gigs per, because the detector wasn't on. And now you can see that all of the will give you a you know, a sort of this.
STFC-RAL-CR03 R61: This number was, I think, because we couldn't do comparison. But you get the 16 number back, and it all looks fine.
STFC-RAL-CR03 R61: like what you do is on top of that you add one Megahertz of RAM triggers
STFC-RAL-CR03 R61: to simulate the operation of the detector. As you're taking data and look at the history of what it looks like. Now you start losing test pulses everywhere.
STFC-RAL-CR03 R61: And then we're told that maybe we can change something of the Rfi from 1.8 volts. To 1.7 8 volts.
STFC-RAL-CR03 R61: And once you do that for this particular deck, you recover quite a lot of what was going on. Now we never managed to recover it completely, but it was really a lot a lot better than before.
STFC-RAL-CR03 R61: So by applying this small change.
STFC-RAL-CR03 R61: we're able to increase the number of photons that this is the number of photons that we get per run and look at the what was happening before and what happened after.
STFC-RAL-CR03 R61: but it's completely clear, and in which, though the effect was smaller. But, you can see, actually put the schedule, you can see. But we actually managed to to get confidence out.
STFC-RAL-CR03 R61: So this is a description, a little bit of what was these are, yeah, these- these were, it's getting used of 2012. The company was starting to explore new ideas of how to make sure that there will be less
STFC-RAL-CR03 R61: less of a
STFC-RAL-CR03 R61: I'm guessing. So they would change the day count they went from 4 to 7 h, increase from 310,
STFC-RAL-CR03 R61: and none of these things make a big difference. But finally.
STFC-RAL-CR03 R61: maybe because of technology constraints. They said that they could include a get their material inside the tuning
STFC-RAL-CR03 R61: and part wars, their life, those of sort of long, the exact same thing
STFC-RAL-CR03 R61: addition, it made a huge difference to the quality of the that we get.
STFC-RAL-CR03 R61: So that was all of the new activities that we got asked about
STFC-RAL-CR03 R61: didn't work fine for the whole of the laptop experience.
STFC-RAL-CR03 R61: and for ls, one, we're gonna have 2 years of no running. We've had to make decisions of what we're gonna do with the that was going on.
STFC-RAL-CR03 R61: but nothing too significant there. At the same time, we're preparing to decide what to do with the Arizo, and this is what we could see as the performance of the the Arato.
STFC-RAL-CR03 R61: The idea was.
STFC-RAL-CR03 R61: let's let's do the thing that should be the most obvious one, which is the separation of ions from proponents. These are 2 extremes of the hydrants, so how well does it work? And you can see, depending on
STFC-RAL-CR03 R61: how many? What is the multiplicity of each event? You get slightly different curves.
STFC-RAL-CR03 R61: but all of them are very close to random choice.
STFC-RAL-CR03 R61: It was clear from from these boards that the the hotel was not actually doing anything much, and going from 2010 to 2012, having improved things significantly.
STFC-RAL-CR03 R61: So that was when we decided that we're gonna stop it. There was a good reason for that as well.
STFC-RAL-CR03 R61: And then we're able to show that the some of the changes that we did actually make a a significant difference. So
STFC-RAL-CR03 R61: in blue here, this, these are performance plots that- that we show the the better they are in this formula, the better they are. This tells you the the efficiency, and then this is the- the. So you want everything to be as close to to the bottom corner on this side, and you can see that the low these are the 2 different polarity at low level 0 8 we have a few fields. Performance is better.
STFC-RAL-CR03 R61: and then at time it gets worse. But then, once you apply that fix with changing that particular duck by, you know, 20 millivolts. Suddenly the performance improves significantly
STFC-RAL-CR03 R61: and we no longer get the issues. Sorry, Anthony, getting back to the aerogel is your aerogel, particularly low, refractive index. Because, I mean, people have used aerogel stable absolutely so. The issue is not the aerogel. The issue was mostly with the performance that we were getting from the Aerogen valve. So it's not as quite as good as the one originally promised.
STFC-RAL-CR03 R61: But then, what really made the difference was the fact that it was in the same volume, the same detector as the gas. So if you have the answer on its own, but it wouldn't be performed as well as original fault, but it would still work.
STFC-RAL-CR03 R61: but by putting it in the same volume as a gas.
STFC-RAL-CR03 R61: So your enclosures didn't work.
STFC-RAL-CR03 R61: Sorry the encoders that you put the error down, and it didn't work, so you couldn't really call that part. But the the resolution wasn't good enough, and
STFC-RAL-CR03 R61: the the main thing that that was the biggest problem is this. So you you share, you know, you go to your bottom detector area. You get a gas ring that's about that size, and then you get an outer ring that's about that size. Now, on that size you have 5 buttons
STFC-RAL-CR03 R61: and the amount of background. Yes, but there is another thing. It's just, you know.
STFC-RAL-CR03 R61: And yeah, that was the plan of getting some new Uk level. One boards. We made a few prototypes, but we never had to do it go through.
STFC-RAL-CR03 R61: And then we did think that already back in 2015 would actually put in this tool
STFC-RAL-CR03 R61: the types that we're planning to use for the Lxb upgrade, and we'll come to that in at the end of the presentation. We didn't mind. It was an ambitious project. We didn't get enough effort. So this didn't happen. But the plan was already back in 2013,
STFC-RAL-CR03 R61: and the other thing that we did one of the issues that we had. We're suffering a little bit from
STFC-RAL-CR03 R61: error transmission on the on the of the occupied.
STFC-RAL-CR03 R61: And we think that we have this issue, because, compared to most of the other subjectors, we have the next round. So you come. You get the long distance fiber into the field. Then you get that where you go to your medium distance fiber towards your and most of the people would just take the fiber straight into the detector. But we have to go into our dark enclosure in a way. So have another handle there.
STFC-RAL-CR03 R61: And
STFC-RAL-CR03 R61: these didn't work particularly well. You you could get potential losses at these bundles, and what we did at the time in 2015 is we use?
STFC-RAL-CR03 R61: I can't remember the actual acronym. You sent a a light pulse, in view of the reflection.
STFC-RAL-CR03 R61: and by measuring how long it takes for the thing to come back. Then you know what we do, and if you get multiple reflections, you can actually see all the interfaces. And this is what you can see here, the various distances. We did that. And then we did that for every fiber, and the ones that we couldn't get the reflection from the very end. We then go and fiddle in the the bus panel, clean a bit more.
STFC-RAL-CR03 R61: and that generally improves the performance of the of the detectors in terms of there's a lowest
STFC-RAL-CR03 R61: sorry I'm running late. So that's fine, we have question, we have questions in between so and now, during 2015, this, this is the Ion feedback development. So we could measure how good. The next video was by measuring something called the Ion Feedback, that was really measuring events that had large clusters, because when the Ion would take the photocopit, we get more than one for the electron, and they would generally go down together.
STFC-RAL-CR03 R61: So something like we had a limit of 5% of antibug, ie. 5% of all events which have a non debug event in them. And so that meant that we had a limit of 0 point 5% per year in the deterioration of the in order to decide whether to include them or not. And you can see the ones together were working really really well. And then this is, we have so many of these plots.
STFC-RAL-CR03 R61: This is how you classify, according to, you know, configured the duration like how much they were changing and time interval of the unfit value they had in the beginning.
STFC-RAL-CR03 R61: And and that tells you that most of the here in the middle are okay. These are not doing particularly well. These are special cases and and things like that. And then it's amazing
STFC-RAL-CR03 R61: thoughts about which we're going to change. So in this one we're very ambitious, we said. Let's see whether we can change enough to be so. We don't have to open up until 2018
STFC-RAL-CR03 R61: other things work. But let me try.
STFC-RAL-CR03 R61: So these were, the Hpds have to change. You can see in call how bad they were. But the other thing that was going on is in order to get consistent time alignment, because you have 2 Hpds per level 0 board, as we would say, we wanted the 2 Hpds that put together on the same level 0 board. We have similar leakage current because the leakage current
STFC-RAL-CR03 R61: determine the timing performance of the season centrally.
STFC-RAL-CR03 R61: So once it's any sort of the experts. What we also wanted to do is move the other experts around in order to match them properly
STFC-RAL-CR03 R61: and look at the scheme.
STFC-RAL-CR03 R61: He was fine and yeah. And and eventually
STFC-RAL-CR03 R61: out of the box was removed.
STFC-RAL-CR03 R61: And then we've got our 1st let let
STFC-RAL-CR03 R61: events as well. And this is a single level event.
STFC-RAL-CR03 R61: I don't think you can do that, but this is one of the things we're not gonna look at.
STFC-RAL-CR03 R61: So we'll come to 2015.
STFC-RAL-CR03 R61: Real excitement here.
STFC-RAL-CR03 R61: Why, so we can remove the A reserve. Now. The main reason why we remove the avatar was remove a little bit material, although the tracking didn't get that much.
STFC-RAL-CR03 R61: But if you look at the actual layout of the detector
STFC-RAL-CR03 R61: behind the aerota, between the aerota and the the bellow. You've got a bit of volume, and that volume is full of gas, and if you remove the box of the aerota or the aero, you get more problems.
STFC-RAL-CR03 R61: So for set of tracks, you can actually get up to 15% more photons. And that should give you a better performance than from the gas, purely from the gas.
STFC-RAL-CR03 R61: So
STFC-RAL-CR03 R61: 1st data coming out in 2015. And what you see here, that was my effort to see, you know. To combine the 2 cares in in green is the new performance, and in red and black is the old performance, and you should be able to see that most of the the green are just a little bit above the red. So you get better. Id, and also below.
STFC-RAL-CR03 R61: The thing is with these steps. You have to be a little bit careful, because you can move the whole thing up and down, depending on how you apply it out. But the fact that
STFC-RAL-CR03 R61: you're moving the efficiency up. And then, if I did down a little bit, just shows you that you actually have better performance. So I was really really happy so far to see the the 1st opportunity.
STFC-RAL-CR03 R61: And yeah, and then one of the other things that you don't expect.
STFC-RAL-CR03 R61: So in 2016 moving on. We always have a little bit of a leak of air inside the the rich one gas, which is generally easy to purify because you can liquefies. So we're doing that during the technical slow. So how do we do it? And then, somehow, the gas expert left for holidays.
STFC-RAL-CR03 R61: And then we were monitoring the gas by measuring the for the the pressure difference between the top and the bottom of the gas. Because and if you have sensitive pressure sensors, you can actually weigh the gas quite well up to maybe 1%, which is really impressive.
STFC-RAL-CR03 R61: And then suddenly, what happened?
STFC-RAL-CR03 R61: The President going off?
STFC-RAL-CR03 R61: And we're starting to think what the hell! Of course I'll be assuring.
STFC-RAL-CR03 R61: Hello!
STFC-RAL-CR03 R61: It turned out.
STFC-RAL-CR03 R61: But somebody has made a mistake, and we're getting one of the we're getting nothing. They were using algorithm for controlling parts of the the gas system.
STFC-RAL-CR03 R61: And we have hardware coming into into each one
STFC-RAL-CR03 R61: just as we're expecting to start date. And of course, if you do that, then the refractive index becomes completely so go down to 30%. I think 40% argument in our volume, and then the best way to fill it up again is just then stall out and start filling out with more fuel 6%, which is really heavy. So fills up quite nice from the bottom.
STFC-RAL-CR03 R61: But yeah, and then, at the conference in 2016, I was able to present
STFC-RAL-CR03 R61: the comparison between before and after we move this, the other cell in detail and momentum.
STFC-RAL-CR03 R61: and you can see that the whole system behaved exactly as we expected. But the important thing was that all the red is better than all the black. So it's not that we could move something around or something. We had actually generally improved the performance of these detectors.
STFC-RAL-CR03 R61: And I think I'm coming soon to the end.
STFC-RAL-CR03 R61: yeah. And then 2016. We've been running these detectors for, you know 8 years.
STFC-RAL-CR03 R61: And suddenly we started to get back.
STFC-RAL-CR03 R61: or an entity would suddenly stop taking data and just send these fun buttons.
STFC-RAL-CR03 R61: and has no idea what this was going on, and for this
STFC-RAL-CR03 R61: more annoying it went by itself without us doing anything.
STFC-RAL-CR03 R61: It was something that was extremely difficult to pick up automatically, because the was just
STFC-RAL-CR03 R61: send these things. But anyway, so we hope we'll wait for a while so that we're going to investigate and then change that point.
STFC-RAL-CR03 R61: the story. I'm not sure I've got enough.
STFC-RAL-CR03 R61: I'll tell you about this if you ask me at the hand. And then one of the things that we did was optimize the software we have now moved to having
STFC-RAL-CR03 R61: some of the reconstruction of of reach of the higher the figure after. After. So it was important to be able to run it. Basically. So Chris Jones has written, all of the software, did an amazing job improving the speed in order to be able to do it quickly.
STFC-RAL-CR03 R61: And that was another reason why we didn't want to share the audio, because, including the other, we just increased the amount of time we take to search through
STFC-RAL-CR03 R61: finally, focus on and everything else.
STFC-RAL-CR03 R61: And yeah, December 2017, we had the alignment of the mirrors running for quite some time, and this is which 2,
STFC-RAL-CR03 R61: and you can see how stable everything is.
STFC-RAL-CR03 R61: We're quite happy with these, and
STFC-RAL-CR03 R61: we're coming really towards the end.
STFC-RAL-CR03 R61: That was one of the last elements for me where physics, physics, and more physics.
STFC-RAL-CR03 R61: So we, the detectors, have really come to their own after
STFC-RAL-CR03 R61: 8 years of running plus 3 years of electron. But before we close, remember that small bit of piece that I showed you well, in 2018, we actually put it in. Now, the thing is, we didn't actually take any out that was too complicated. We just put them in.
STFC-RAL-CR03 R61: And the plan data here they could see just a little bit of line that we come in at the gaps between the eighties.
STFC-RAL-CR03 R61: I'm
STFC-RAL-CR03 R61: the idea was, you know, one. And do it, you know, just to see how these these things work.
STFC-RAL-CR03 R61: And
STFC-RAL-CR03 R61: we thought that by going from which was a custom made device, had all these problems that we're seeing
STFC-RAL-CR03 R61: to a device that comes from a company like how much of this? We would have no issues with the button detectors.
STFC-RAL-CR03 R61: What?
STFC-RAL-CR03 R61: Okay?
STFC-RAL-CR03 R61: This is what we discovered
STFC-RAL-CR03 R61: by having these detectors in reach 2 before the end of of round 2 and started looking at things. We've noticed that, you know this is the signal. This is a look at mistake.
STFC-RAL-CR03 R61: We get a little bit of background in these devices at a different time. These are time in nanoseconds, you know 4,000 nanoseconds later. Remember 25 nanoseconds throughout the process. In the beginning we just saw it. We thought, it's some sort of thing that we haven't calculated for, but no other part we did. We couldn't figure it. And after a lot and a lot of investigation in the lab, we discovered that what would actually happen is that the process of multiplying the pod electron
STFC-RAL-CR03 R61: would create some ions and go back to the photopathic again. And that will happen mostly at the edges of the tube, because the dynamic structure
STFC-RAL-CR03 R61: individually wouldn't happen. So you can see the pattern.
STFC-RAL-CR03 R61: You get it mostly at the top and the and the bottom row
STFC-RAL-CR03 R61: and and yeah, that was quite important. We're able to feed that information back to how much and how much you
STFC-RAL-CR03 R61: realize that they sort of knew about it, but they hadn't really thought it was important.
STFC-RAL-CR03 R61: So then they actually started making modification to the tubes, including a little bit extra material against those designs from going back to the and we developed front and electronics for the Lhc that have a front end gauge of a few nanoseconds rather than the full 25 nanoseconds, which means that we can remove something like most of you know, we can remove 7 eights in principle for this platform.
STFC-RAL-CR03 R61: but that is the end of
STFC-RAL-CR03 R61: the advantage of which one of which one and 2 in one month will be, let's say, okay.
STFC-RAL-CR03 R61: The type of questions. Chris.
STFC-RAL-CR03 R61: Yes, you showed a 1 heavy iron picture to demonstrate that
STFC-RAL-CR03 R61: you were alive. And could you do any particle id in these conditions. Yes. Well, not in these conditions that I showed. But what? So the the activity of the detector of the entire syntology.
STFC-RAL-CR03 R61: So I think we could do.
STFC-RAL-CR03 R61: I think it works the other way around 0, central? Yeah, something like this. I think we could do up to
STFC-RAL-CR03 R61: 30%. Sure, we will do non sample provisions.
STFC-RAL-CR03 R61: peripheral collisions we could do but central collisions. No, I mean, the other thing is, somebody calculated that the central collision in the artifact area would have an occupancy of 200%.
STFC-RAL-CR03 R61: So yeah, nowadays we can do better. But now we can go. I think we could do up to 30 now can do up to 70 or the other way around which way it goes. But now we can do more than half of the detector works for
STFC-RAL-CR03 R61: a word or 2 on how it's going in round 3, and and the plans for h round 3 is going quite well. So when we did the upgrade. Our main aim was build detectors risk detectors that would give us
STFC-RAL-CR03 R61: the same performance that we've had inbound running to. At least, you know, 5. We've shown that we actually improved a little bit to the performance.
STFC-RAL-CR03 R61: which is which is really good news. And yeah, the detectors are getting better and better.
STFC-RAL-CR03 R61: So hopefully you won't
STFC-RAL-CR03 R61: upgrade to. We'll have to say we. We're not sure what to detect. Those upgrade to. The main thing is complete timing
STFC-RAL-CR03 R61: and potentially go to silicon for the multipliers, but silicon for the multipliers
STFC-RAL-CR03 R61: we normally survive if we keep them down to live united interpretation.
STFC-RAL-CR03 R61: And that is the challenging for you. When is upgrade to 2034?
STFC-RAL-CR03 R61: You started by saying it was the best rich detector ever which you didn't make any comparisons with any
STFC-RAL-CR03 R61: so weird? The the thing is, if you if you only look at performance in terms of
STFC-RAL-CR03 R61: efficiency, and you say the these are very standard, I would say there is better, so that I can do much better like the one thing, the the risk detector of an 62
STFC-RAL-CR03 R61: can get the rejection of news buying 1,000, something like that. It's 50.
STFC-RAL-CR03 R61: But then, if you ask anybody else, there is that because how many tracks do you have per event.
STFC-RAL-CR03 R61: The answer is one, sometimes 3.
STFC-RAL-CR03 R61: Right now let's we upgrade. You know we operate with 500 trucks in the detector, and the momentum range is literally from 2 to a hundred series.
STFC-RAL-CR03 R61: There is no other detector that can do such an extent. I mean the only detector, you know. They called it the high mountain bid to do 5 to 90
STFC-RAL-CR03 R61: so if you look at the momentum range and the number of particles that are going through all the vectors.
STFC-RAL-CR03 R61: I'll think it's interested.
STFC-RAL-CR03 R61: How challenging was it to get these exemptions for this CFC usage
STFC-RAL-CR03 R61: the at the moment? It's not an issue using C. 4. And it's not a problem
STFC-RAL-CR03 R61: because it's not forbidden yet to use it. The only challenge was to make sure that we had enough of the gas because it's not been made much anymore.
STFC-RAL-CR03 R61: But when we realize that the comments gonna stop making, we bought a lot of it
STFC-RAL-CR03 R61: when we sold some bodies.
STFC-RAL-CR03 R61: Oh, no, no, it was compass. I think I can't remember, because they also have yeah compass
STFC-RAL-CR03 R61: with the promise that if we needed it we'd get back.
STFC-RAL-CR03 R61: So it's all about minimizing leaks. If- if your system is leak free, then in principle, it's not a problem.
STFC-RAL-CR03 R61: right? It's a closed system. You keep the gas.
STFC-RAL-CR03 R61: It doesn't escape out into the atmosphere. You're not causing any trouble and kept it where? Kept it? No, I mean inside the detector, right? The detector is full of the gas as long as yeah, no, no, but I mean when you say you bought it in advance a lot. Oh, sir, certainly.
STFC-RAL-CR03 R61: and the company, which is one of the main manufacturers, is in Uk.
STFC-RAL-CR03 R61: Some other company goes a little bit, they always say, Oh, that's the last book, and then, a couple of years later, they say, Oh, by the way, we've got some more.
STFC-RAL-CR03 R61: It is sorry just on that point. Actually, then. So in terms of sense overall, like impact from footprint from CFC leaks.
STFC-RAL-CR03 R61: Where does the other 3, which is that
STFC-RAL-CR03 R61: we used to in one which has now been changed with a much lower on the global
STFC-RAL-CR03 R61: and generally in the regions trying to circulate some of the. But I think they're not doing as well as us.
STFC-RAL-CR03 R61: But if you look at the outlets and Cms, we are a small, small fraction. Yeah.
STFC-RAL-CR03 R61: W. 19.
STFC-RAL-CR03 R61: Yeah, that was a great talk, Anton, that very nicely illustrates,
STFC-RAL-CR03 R61: the importance of importance of operations, and how difficult it can be to get all those things right. Figure out what's going on. Just a just a couple of questions. The so the aerogel by removing it.
STFC-RAL-CR03 R61: That's removing a bit of the performance at low momentum.
STFC-RAL-CR03 R61: Not really. It was. No, we didn't do any. No, a a bit of the predicted
STFC-RAL-CR03 R61: the the original reason the aerial was put in there. Yes, was for the momentum stuff which was supposed to enhance physics properties and had an impact on tagging.
STFC-RAL-CR03 R61: Yeah, in particular. So how much of an impact on the physics performance.
STFC-RAL-CR03 R61: Well, that is very difficult, you know. Half- half the apps would be performing the way we just expect it probably would be. Don't think it would be a big thing.
STFC-RAL-CR03 R61: Well, there were, but because there were a lot of there was a lot of controversy about including it. In the 1st place, because various other experiments had failed.
STFC-RAL-CR03 R61: and there were physics, arguments for pushing, to put it in
STFC-RAL-CR03 R61: to improve that I mean, the business argument was that we could do mostly play importance separation.
STFC-RAL-CR03 R61: So the in in C sports, then the 9 and a half dv.
STFC-RAL-CR03 R61: so below 9 and 5 tb, you cannot do came on inspiration at all.
STFC-RAL-CR03 R61: You can do K. 5 by operating it in beta mode, because you get some light from combined. No light. Okay. Actually, it works well, and it improved by moving out a little.
STFC-RAL-CR03 R61: but so we couldn't. But but I don't know. So we are looking a little bit. Now, some of these things, because of the idea of having thoughts not very good, for you can do similar things that we do. Let's say with the answer in the past. And yeah, the banking improves. If you can do problem separation at low momentum, you can improve the banking.
STFC-RAL-CR03 R61: It's difficult to know what is significant. Right? You can go maybe from 3 to 4%.
STFC-RAL-CR03 R61: So you can say improved by 1%. But you can also say improved it by 30%,
STFC-RAL-CR03 R61: depending on on how you you see things.
STFC-RAL-CR03 R61: But at the end of the day the question was, did work or not, and the answer was, If we will do
STFC-RAL-CR03 R61: okay, great thanks. And then another question on the pixels that you talked about.
STFC-RAL-CR03 R61: Was there any knowledge of? Why these were dying then?
STFC-RAL-CR03 R61: No, not a hundred percent. Sure, I know that we have a similar problem in podcast now, not really one.
STFC-RAL-CR03 R61: And these are gonna be the same devices for the current use. But now we know about it.
STFC-RAL-CR03 R61: or I'm not sure but anyway, but we know now what was going on with the
STFC-RAL-CR03 R61: into the Dtlx class, or something like this. I'm not sure what they're called
STFC-RAL-CR03 R61: So what happens is without guessing.
STFC-RAL-CR03 R61: So your fiber gets nerdy.
STFC-RAL-CR03 R61: After a while we have to clear them up.
STFC-RAL-CR03 R61: So when they realize that they took a a bunch of of these things and they baked them out, and that seems to have helped. So all of which one has baked out of these devices. So they look. Okay, reach 2, and a lot of them are not so. Every now and then go and have a look
STFC-RAL-CR03 R61: in. Decide to kind of communicate with this event.
STFC-RAL-CR03 R61: But I would say for some Spanish vision. The
STFC-RAL-CR03 R61: configuration side of things seems not be as good as in in the original. So it's all done with lasers. And you know the DVD. And DVD. Sca. And some of these things are a little bit
STFC-RAL-CR03 R61: music.
STFC-RAL-CR03 R61: You're aware of the Atlas experience of humidity.
STFC-RAL-CR03 R61: but ours died in when when we were keeping in air, but not when we keep them in a dry atmosphere.
STFC-RAL-CR03 R61: Okay, interesting. But I mean, these devices work in dry atmosphere all the time.
STFC-RAL-CR03 R61: No questions in the room.
STFC-RAL-CR03 R61: Does anybody want to listen to the story behind those? Yes. Page 15. What's your story?
STFC-RAL-CR03 R61: Right? Did you see these 2 missing page videos here.
STFC-RAL-CR03 R61: What happened was in, I think, probably 2020, 11, or 2012.
STFC-RAL-CR03 R61: We will. Just when we switch them on these ones. They generally wouldn't need to be over there.
STFC-RAL-CR03 R61: So
STFC-RAL-CR03 R61: we ended up with a very specific pattern, which was that when you switch them on they work fine
STFC-RAL-CR03 R61: as they warm up. They stop working. When you reach operational temperature, they work again.
STFC-RAL-CR03 R61: So the-the- the way would happen is we switch them on, configure them
STFC-RAL-CR03 R61: any effort to communicate with them. After that.
STFC-RAL-CR03 R61: if it came back with errors, we just ignore it.
STFC-RAL-CR03 R61: and by the time we got into stable rooms this would have been a situation where they're working again.
STFC-RAL-CR03 R61: So we just the fact that we couldn't communicate with it, would not we just ignore it? Right? So eventually we reach one. And I'm telling our experts
STFC-RAL-CR03 R61: we need to do something about these things, only I've just said when they're cold they're working fine, and when they're hot. They're working fine. And when they're room temperature, they're working fine. But they're not working fine when they're about 15 meters.
STFC-RAL-CR03 R61: and that we couldn't really produce a lot.
STFC-RAL-CR03 R61: So there were 2 possible sources of issues. One was what we used to call the level 0 board and the other board. They want to provide.
STFC-RAL-CR03 R61: So during Ls one, we placed both of these ports.
STFC-RAL-CR03 R61: so everything seems to be fine. We put them in switch on the cooling switch them on.
STFC-RAL-CR03 R61: This don't work.
STFC-RAL-CR03 R61: I want to cry. How many?
STFC-RAL-CR03 R61: How can that be? Right? We we changed everything that was connected to these, to these things. And then, in 2017. 2 years later we were doing some repairs because we didn't manage to get Rich Farm to work all the way, and I'm telling ken ken
STFC-RAL-CR03 R61: do something. Figure out what's going on. So he- he's downstairs on the phone upstairs in the control room and he says, Send the configure command.
STFC-RAL-CR03 R61: He failed. What did he do?
STFC-RAL-CR03 R61: It was a cable, but on connecting the level 0 board and the other remote.
STFC-RAL-CR03 R61: This was a flat table.
STFC-RAL-CR03 R61: Likelihoods at the time, or something like that, and when they change the 2 boards they get the same cables.
STFC-RAL-CR03 R61: Now, how many cable give you such a consistent situation? Where it won't. It works called. It works well. It doesn't work in between. And every single time we do exactly the same thing.
STFC-RAL-CR03 R61: I guess it must have been the connector.
STFC-RAL-CR03 R61: And after that it worked.
STFC-RAL-CR03 R61: Okay. But that's- that's good.
STFC-RAL-CR03 R61: Well, at least you didn't find super luminary.
STFC-RAL-CR03 R61: Okay? Oh, one last quick question that the
STFC-RAL-CR03 R61: you were talking about a board that need a level one board on page 23 that needed work doing on it. And he said it was a Uk
STFC-RAL-CR03 R61: group sport. You didn't say which Uk group and breeze.
STFC-RAL-CR03 R61: Okay, I mean, I hate the once
STFC-RAL-CR03 R61: once it was pointed out what the drop reports. They they also need to increase, and, I should say.
STFC-RAL-CR03 R61: was a little bit of background. So these were supposed to be part of the level one figure, but was eventually just cut out completely. We want the 11 figure
STFC-RAL-CR03 R61: didn't really have a proposal this time. And then at that moment, once the- the trigger was removed, it was decided that the rest of it, but the whole board that we call the Tell one.
STFC-RAL-CR03 R61: But Cambridge had already these boards, and they were like, well what was supposed to do, and because we were not part of the original figure, our boards were actually significantly cheaper than their board.
STFC-RAL-CR03 R61: And can we still going to lose the opportunity to develop this ports and everything else? So it was decided
STFC-RAL-CR03 R61: in a little bit of a political fashion if you want as well, but the rich would keep the original codes, and the rest would use the new boards. So these were called the Uk level ones, while everything was the 3rd one.
STFC-RAL-CR03 R61: they were frequently failed. Frequent failures of the day. Once
STFC-RAL-CR03 R61: none of the details. We had a plan of what you need to do. If one of these boards, hey? Then it was not an easy thing, because, replacing one of these boards would require quite significantly. Configuration of the online system, you know, put the new board in, and that kind of thing. So
STFC-RAL-CR03 R61: We never had to deal with this.
STFC-RAL-CR03 R61: None of the both failed. There was one that had an issue once, but it was that the the CC. Was this bit over here, the communication.
STFC-RAL-CR03 R61: and we can send this going to respond.
STFC-RAL-CR03 R61: and if anything was to go wrong, let's say some sort of atmosphere, or something impressive, set button on the crate.
STFC-RAL-CR03 R61: 2 min later the board would come up again will be fine, excellent.
STFC-RAL-CR03 R61: but almost at the end. I don't see any questions from Zoom, so let's hang the speaker again.
STFC-RAL-CR03 R61: Hope you are joining us, so please feel free to join us once we check it off. Thank you.