STFC-RAL-CR03 R61: So, let me start by introducing our speaker today.
STFC-RAL-CR03 R61: Rianna. She's a lecturer at the University of Sheffield.
STFC-RAL-CR03 R61: And she has been widely involved in liquid album nutritional experiment since 2015. She's currently the co-convenant of the oscillation group.
STFC-RAL-CR03 R61: at the SBMD experiment, and at the dunes, and it's the dunes Physics Calibration Group Covina.
STFC-RAL-CR03 R61: And today, this talk will introduce the SB&D experiment, its exciting physics goals, and the expected impact on the future of particle physics. So, join me in welcoming Briano.
STFC-RAL-CR03 R61: None.
STFC-RAL-CR03 R61: Yeah, so, as Ivana has said, I will be talking to you today about SVND. I don't believe Raoul is involved in SB&D, and I'm going to be assuming that from now on. So I will introduce, some of the sort of physics, the underlying physics that we are working towards, solving out, and then I will walk through how the detector works.
STFC-RAL-CR03 R61: I will talk about, I should probably move to my broken slide here. I will…
STFC-RAL-CR03 R61: It might need to click. Oh, you might need to click the…
STFC-RAL-CR03 R61: Otherwise, again, to make it work. Yeah, okay, oh, I haven't, that's okay.
STFC-RAL-CR03 R61: Ivana, are you recording? Yes, yes.
STFC-RAL-CR03 R61: It's all working, isn't it? It was.
STFC-RAL-CR03 R61: If you click on the slides again. Yep. There you go. Oh, we have something. Okay, this is the slide I wanted, let's see… okay.
STFC-RAL-CR03 R61: We have movement. Great. Yes, so I will start by introducing the short baseline experimental neutrino physics landscape. I will then talk through liquid argon detection in general in the context of neutrino physics, experimental neutrino physics. I will then talk very much more specifically about the short baseline near detector, which is the focus of this talk.
STFC-RAL-CR03 R61: And then I'll run through the SPMB Physics program in each of its three major parts.
STFC-RAL-CR03 R61: And then I'll, get to talk to you about how we got to the point of operating SVND and where we are at right now.
STFC-RAL-CR03 R61: Yeah, so getting straight into it.
STFC-RAL-CR03 R61: I'm hoping this is not news to anybody, but of course, neutrino oscillations were discovered at the turn of the century, through a combination of measurements by superchase and snow, and was awarded the 2015 Nobel Prize. And the reason I'm bringing this up is just to highlight the fact that basically since then, experimental neutrino physics has largely been involved in trying to constrain the parameters which cover neutrino oscillations.
STFC-RAL-CR03 R61: Get precision measurements on those, and decipher any anomalies that we see along the way.
STFC-RAL-CR03 R61: And so the equation at the top here is the equation that primarily governs neutrino oscillations. It's parameterized by the PM and X mixing matrix that I've highlighted in red, and the squared mass splitting that I've highlighted in blue. And this is an expanded version of PM and X mix here.
STFC-RAL-CR03 R61: And this is the current status of the measurement landscape for these parameters. Nufit was down 2 days ago, but thankfully, Google Images stayed the day. So this is as of, I think, 2020… November 2025, and I've specifically just pulled out the, normal, normal ordering assumptions, with the junk,
STFC-RAL-CR03 R61: super mathematics as well. So this is kind of current status of neutrino oscillation physics in the broad space.
STFC-RAL-CR03 R61: However.
STFC-RAL-CR03 R61: I'm not gonna talk specifically about active neutrino oscillations, I will get to that shortly, but I'm going to narrow us down towards the short baseline regime as we go through here now. So yeah, the way that we measure these parameters is by, setting up experiments with, specific
STFC-RAL-CR03 R61: energy ranges and what we call baselines, i.e. the distance into a detector to the source of the neutrinos. And these two parameters are L and E.
STFC-RAL-CR03 R61: And so this can be done to, basically tune your experiment to any given set of parameters that you would like to measure. So for instance, in the react… what we call the reactor range, reactor neutrino oscillation experiments, moving towards the solar range, although that baseline is so large, it's very hard to sort of show on a plot.
STFC-RAL-CR03 R61: If you look at the x-axis of this distribution, we have an elevary, up to, sort of.
STFC-RAL-CR03 R61: 100,000, and you can see the general shape of what we call the slow oscillations. And you can also see within that, what we call fast oscillations. And this is because the,
STFC-RAL-CR03 R61: Oscillation probability is a summation over multiple mass splittings, and mass spread splittings govern the frequency of the oscillations.
STFC-RAL-CR03 R61: And so at this range, you are largely sensitive to delta M squared 2, 2, 1, which is the slow oscillation. So I've drawn sort of, like, dashed lines over it so you can see the sort of shape. But of course, it would be very, very difficult to unpick the really fast oscillations at this rate… at this range.
STFC-RAL-CR03 R61: So what you can do instead is you can place your experiment in a different location. I don't know, backwards, probably.
STFC-RAL-CR03 R61: If you place your experiment in a different location and effectively zoom in on this x-axis, you can then pick out the behavior of the faster oscillations, but you then lose sensitivities for slower oscillations. So, in the long baseline accelerator atmospheric region, we have elevreaves up to sort of 1,000, and you become more sensitive to the delta M squared 3, 1 delta M232.
STFC-RAL-CR03 R61: And if you zoom in even further, so what we're effectively doing is I've shown you the broad scale here. For the long baseline, I've zoomed in just to here.
STFC-RAL-CR03 R61: And then for the short baseline, I've zoomed in just to here. And so you can see that at this short baseline, where elevator heads up to about 1, you should not be sensitive to any of these oscillations whatsoever.
STFC-RAL-CR03 R61: So yeah, that's why these experiments are set up, are to be able to measure things that are not necessarily related to these oscillations.
STFC-RAL-CR03 R61: That being said.
STFC-RAL-CR03 R61: Short baseline experiments of gallium reactor and accelerator setups have all, many of them have reported anomalous data. So they weren't necessarily looking for oscillations, but they have observed signals which could be construed as an excess or a deficit in, particular neutrino flavors. One example, two examples are LSMD and Miniboom, and they observed what we call the low energy
STFC-RAL-CR03 R61: So you can see the data sort of sitting quite high above, the expectation at these low energies.
STFC-RAL-CR03 R61: And this is, like I say, called the low energy excess, and then from there, many, many, many theories, I believe about 100 theories exist to try and explain this, but the dominant one, which has been constructed to try and explain away, this excess, is the existence of sterile neutrinos. So the idea would be, if your active neutrinos oscillate away.
STFC-RAL-CR03 R61: from the, active regime into a sterile, and then back into an active flavor, you would see an excess of, electron neutrinos that are not accounted for in the standard active, oscillation framework. And so, because Ellison D and Maybone observed this excess, microboom was set up.
STFC-RAL-CR03 R61: Don't worry, I'll be the next question.
STFC-RAL-CR03 R61: Okay, so, Mini Blue has a baseline of around…
STFC-RAL-CR03 R61: 500 meters from the source of the neutrinos, and my program was built in pretty much exactly the same spot at 470 meters, but with a completely different detector technology in order to better characterize this excess and constrain the systematics that Minibune and LSMB were unable to, nail down.
STFC-RAL-CR03 R61: And the main feature is that, Miniboon and LSND could not differentiate between electromagnetic showers produced by electrons and photons, whereas LART PCs, such as MicroBoot, can distinguish between them. And so that was their main systematic, and MicroBoom was set up to try and mitigate that. Microboom, however, did not see any hint of the low energy excess, and they've since, also put out a sensitivity in the
STFC-RAL-CR03 R61: 3 plus 1 sterile oscillation hypothesis. So 3 plus 1 is 3 active, plus 1 hypothesized sterile. They covered a large portion of the parameter space at 95% confidence level, and so, so far, the conclusion is steriles are not the answer to this problem.
STFC-RAL-CR03 R61: But it's not…
STFC-RAL-CR03 R61: 100% conclusive, because you can't really get to 100%, but SBN, the Shore Baseline Nutrient Program at Fermilab, will probe all three of the possible sterile solution channels we can search, which are newly appearance, and new, new, and new disappearance.
STFC-RAL-CR03 R61: In order to basically push these orange lines as far into these corners as you can to cover the majority of the parameter space, and once and for all, rule out the existence, sorry, confirm or rule out the existence. I am the oscillation convener, and I am a skeptic. But yeah.
STFC-RAL-CR03 R61: So that's kind of like the background, that's the motivation for the construction of these experiments. So now I will talk about more of the detectors themselves. So…
STFC-RAL-CR03 R61: This is a blown-up cartoon diagram of the shore baseline near detector. So the way that… the way that this works, we have two time projection chambers here, separated by a cathode plane, with anode plane assemblies on either side, and photon detection systems at the back. So if a neutrino enters the BMV, sort of in this direction, say, into the page,
STFC-RAL-CR03 R61: If it interacts within the detector, it will produce a combination of charged and neutral particles, and those charged and neutral particles will continue to propagate through the detector.
STFC-RAL-CR03 R61: As the charged particles propagate, they ionize the argon, electrons are produced, and they are drifted under an electric field towards the anode plane. So the electric field is constructed, throughout the… through the cathode anode plane, system.
STFC-RAL-CR03 R61: Simultaneously, as soon as those particles,
STFC-RAL-CR03 R61: deposit anything in the detector, scintillation photons are produced, and they are immediately collected instantaneously by our photon detection system. So that gives you what we call T0, the initial time, of the propagation of those particles. And so what we can do is we can use a combination of geometric and kinematic and timing information to fully reconstruct
STFC-RAL-CR03 R61: three-dimensional images of the final stage particles produced when the neutrons are inside wood.
STFC-RAL-CR03 R61: And the reason we have two drift therapists
STFC-RAL-CR03 R61: drift volumes in SVMV, is because the electrons can get absorbed and not make it to the anode plane, so you have to have, an optimized drift distance for those electrons to travel in order to collect as many of them as possible. So to maximize the size of the detector, we've split it in half so you have two drift volumes, to maximize the, electron collection efficiency.
STFC-RAL-CR03 R61: SB&D… so that's sort of… that was LARTPCs in general, under a cartoon of SBMD, but I'll talk more about, sort of, SBN and SBMD now, as well.
STFC-RAL-CR03 R61: The Shore Baseline Neutrino Program is located in the booster neutrino beamline at Fermilab, so we have the target hole here. The beam is fired through SBMD at 110 meters awake from the source.
STFC-RAL-CR03 R61: through microgreen at 470, the far detect from East Icarus at 600 meters.
STFC-RAL-CR03 R61: The SPM program currently consists of the two, the near cloud detector system, so just SBND and Icarus.
STFC-RAL-CR03 R61: both from the booster neutrino beam, and these have been designed to resolve more broadly the short baseline anomalies that have been observed in the search for active, neutrino oscillations, and more primarily to actually search for sterile neutrinos as well. But all three of these detectors have and will continue to make, individual physics measurements as well. They've got reasonably large physics programs
STFC-RAL-CR03 R61: the sort of small-scale experiments and super things. And because they're all LARCPCs in effectively different generations, they are each testing components for June, and so we'll have, sort of, operational construction and, expertise experience building for June as well.
STFC-RAL-CR03 R61: So loads of great reasons to use these detectors. Yeah, so a little bit about the beam.
STFC-RAL-CR03 R61: The booster neutrino beam is primarily muon neutrinos, around 94%, but it does have intrinsic contributions from anti-muons, electrons, and anti-electron neutrinos as well. It's a really well-understood beam. It was also used by Miniboom, the predecessor to MicroBoom. So we've got excellent flux models. We still, of course, have to constrain the uncertainties. The peak energy of the beam is around 0.8 GeV,
STFC-RAL-CR03 R61: And SB&D will hopefully collect around 10E20 POT of, data in its lifetime. And so what this corresponds to in terms of, neutrinos is around,
STFC-RAL-CR03 R61: just under 3 million neutrinos per year.
STFC-RAL-CR03 R61: And an interesting feature of, the composition of our, beam, or the neutrinos in our beam, is that the muon, neutrino, and electron-neutrino fluxes are primarily produced through two- and three body, decays, respectively, and we can use this, in a, in a…
STFC-RAL-CR03 R61: particular way we can't solve that shortly. But yeah, I'll refer back to this later.
STFC-RAL-CR03 R61: Yeah, so…
STFC-RAL-CR03 R61: SBMD is a near-deck probe already mentioned this in the short baseline Neutrino program. It has 112 tonnes of liquid argon in its full active volume, and it's 110 meters from the target, and as I say, we say it records over 2 million, but I'm pretty sure we got just under 3 million in the first year of running, which corresponds to, in total, it would be 10 to 20 times, or 20 to 30 times
STFC-RAL-CR03 R61: more neutrino-argon interaction data than is currently available. And so on the right-hand side here, I'm showing a breakdown of tough.
STFC-RAL-CR03 R61: Of muon neutrino, Final states, and at the bottom, electronutrino, final seats,
STFC-RAL-CR03 R61: All charge current were broken down into the types of particles you can expect to see. So the dominant topology in both cases has no charge pione in the final state, followed by one charged pion, followed by one electron pion, followed by some higher multiplicity of any flavor of pione.
STFC-RAL-CR03 R61: And that is true to both, muon and electron neutrinos, and this is a really, really powerful, fact that we can utilize to do, precision physics, which I'll talk about later.
STFC-RAL-CR03 R61: The feature I said I'd come back to is the fact that SBMD is positioned ever so slightly off the center of the beam line, and what this means is that… well, in general, what this means is that the neutrinos enter the detector from what we call off-axis angles, so the spread is sort of demonstrated here in 8 angular beams.
STFC-RAL-CR03 R61: And that means we can separate… effectively separate the detector into off-axis angle segments, and it's… if you're looking at the front face here, this sort of…
STFC-RAL-CR03 R61: concentric circular, effect is shown, so each of the concentric circles will be one off-axis detector, and because of the high rate of neutrinos, we can expect to see at least 10,000 new neutrinos in every segment, so we're still statistically significant as well. And just to give reference, a 1 degree off-axis angle, SBMD, just corresponds to 2 meters at front face.
STFC-RAL-CR03 R61: It's got a 4 meter, front face, whereas in June, in the geofism setup, 1 degree corresponds to 10 meters at the front face. So this means we can utilize the prism,
STFC-RAL-CR03 R61: setup without moving the detector. We still get the impact of the off-axis angular effect, which, again, I'll talk about shortly.
STFC-RAL-CR03 R61: without moving the detector, and with a huge abundance of statistics as well. And an initial demonstration here, this is the neutrino energy spectrum. The darkest line is the smallest off-axis angle, and the most yellow line is the largest off-axis angle, so you can see that as you move further off-axis.
STFC-RAL-CR03 R61: the peak reduces, but it also narrows, so you have a much stronger handle on your flux, by moving off-axis, and so you can do combinatorics at the near detector that better mimic your far detector, neutrino energy spectrum. Just very helpful for fitting, in oscillations.
STFC-RAL-CR03 R61: Okay.
STFC-RAL-CR03 R61: The TPC in general.
STFC-RAL-CR03 R61: We have, a pretty novel photon detection system. We are testing the XR repupas, which are, contained light bars. The Dune, this is what one, photon detection system module looks like, and they're arranged in this, array you can see here as a demonstration. Like I said before, on the farthest base of the X dimension and the drift dimension.
STFC-RAL-CR03 R61: It will also have POTs. It's surrounded by a field cage to hold the electric field at 500 volts per centimeter. The electronics are fully submerged in the cold, so that minimizes, well, it optimizes our noise reduction. And then we have, anode planes, so…
STFC-RAL-CR03 R61: In front of the PDFs, the proton detection system are the anode plane assemblies.
STFC-RAL-CR03 R61: So this is 3 wire planes, one after another, each with 3 millimeter separation on copper beryllium wires. One plane, the wires are at the vertical, and the other two planes, they are plus and minus 60 degrees from the vertical, and this is what gives us millimeter-scale precision, on the electrons that we collect to reconstruct the, the final state particles.
STFC-RAL-CR03 R61: And finally, the cathode plane assembly is the one that splits the detector in two, and this has TPD-coated reflective foils, so that because the scintillatria photons are produced isotropically, we can maximize the, yield of our photons, by allowing them to be reflected at the cathode and then collected again at the photon detection system. And so that, the reason they're, they're,
STFC-RAL-CR03 R61: compared to those figures to the PMT, what would maybe be like.
STFC-RAL-CR03 R61: Sorry. That, produce a unique guarantee performance.
STFC-RAL-CR03 R61: We also have a cosmic ray tagging system, so SBND is located on the surface of the Earth, and of course that means we have an abundance of cosmic rays, and because our primary signal is muon neutrinos, and therefore muons, cosmic ray muons are a very large background to our dominant topologies. So we have a really robust cosmic ray tagging system with full high coverage of the detector, so it sits around all sides.
STFC-RAL-CR03 R61: We have a bonus panel on the top as well, so you can do telescopic tagging, because most of our cosmic rays are downward going. So you can… I think we get something like 99% rejection by my view. It's…
STFC-RAL-CR03 R61: a very effective cosmic brain rejection, capability. And these are just constructed of scintillation strips that you can pinpoint the location of the cosmic brick hits in.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: Physics. As I mentioned before, SBMD will provide the largest data of, the largest neutrino album cross-section dataset, in our energy range, and a key…
STFC-RAL-CR03 R61: one of the reasons this is super important is because we are dealing with argon. So, the neutrino interaction, models on, sort of, individual nuclei are reasonably well understood and well constrained, but as soon as you plot that initial interaction model inside a heavy nucleus like argon with 40 protocols and neutrons, and at our energy range, you are dominated by
STFC-RAL-CR03 R61: Intra-nuclear interactions.
STFC-RAL-CR03 R61: Anything can happen before those particles leave. So in this example, say your, muon neutrino interacts with a proton to produce a neutron and a charged particle. This is very cartoonish, bear with me.
STFC-RAL-CR03 R61: The neutron could never escape the nucleus, the pione could do various different things to the point where, rather than seeing just a charged pion in the final state, you end up seeing two charged and two neutral pions.
STFC-RAL-CR03 R61: So what this means…
STFC-RAL-CR03 R61: Is that we have to be able to model, everything, including the initial neutrino interaction with the nucleon, the nucleus itself to predict what could happen, and the final state interactions which could occur before anything leaves the nucleus, because it's the particles that we observe that we have to use to reconstruct exactly what the neutrino did in the detector.
STFC-RAL-CR03 R61: So this is a real challenge for liquid argon, but it's a very, very interesting one, in my opinion.
STFC-RAL-CR03 R61: And so this is… I've pretty much covered this, but this is like a cartoonized version of what I was saying. So you have this primary interaction with the neutrino, involved with the nuclear model, hadron transport, or FSI, and ifronization occurs as well, you've got to model that.
STFC-RAL-CR03 R61: And so what we're aiming to do is utilize the SVMB data set to constrain each of these components as best as we possibly can, to then propagate those into our Monte Carlo models in June.
STFC-RAL-CR03 R61: And the reason we can do this at SBMD is that statistical significance not only puts us in the systematically limited routine, but it means we can look at really, really final state.
STFC-RAL-CR03 R61: To try and pinpoint, correlations between, particular final state configurations and,
STFC-RAL-CR03 R61: final state interactions, nuclear modeling, and initial interactions which take place. So you can break down, for instance, a topology that has no ions in the final state into really granular numbers of protons.
STFC-RAL-CR03 R61: You can, again, have granularity in your plan on final state, but you can also, with some significance, look at more exotic animals, like ca-ons, bagels, lambdas, piglons. And we can do that,
STFC-RAL-CR03 R61: Yeah, we can react reasonably heavily, I believe.
STFC-RAL-CR03 R61: So this is the… this is the breakdown of the neonutrino charge current event rate. In general, that we look at truth level, just looking at a gene interaction simulation, not by any, detector effects yet. This is the fundamental what could happen, and then neutral current is listed at the bottom, and the intrinsic component of the electron,
STFC-RAL-CR03 R61: Neutrinos from the booster neutrino beam are also statistically significant, which is pretty unique. So we can make electron-neutrino cross-section measurements, also broken down into those final states, just by looking at the backgrounds of the beam, which is very helpful and very cool.
STFC-RAL-CR03 R61: So that is… that is the sort of way that we utilize the power of SVMD bundles with our cross-section models.
STFC-RAL-CR03 R61: But we can also utilize the PRISM feature of the SBMD to better constrain flux. And this is really important in the, acceleration analysis in Koppola, because the flux of the neutrinos at the near detector and the flux of the neutrinos at the far detector, albeit from the same view, because of dispersion, aren't necessarily a one-to-one mapping. But what you can do, if you separate the detector into the off-axis angles.
STFC-RAL-CR03 R61: And pull out these different, energy…
STFC-RAL-CR03 R61: spectrum distributions, you can almost do a summation of them to model the PAR detectors,
STFC-RAL-CR03 R61: energy distribution better to the point where when you're fitting from there to hard detector, you can better constrain both the flux and the cross-sections and the systematics. And one of the, another feature of the PRISM setup, which is very, very useful, is the fact that
STFC-RAL-CR03 R61: Electron neutrinos are produced in three-body blades, and muon neutrinos are produced in two-body blades, because that quite significantly modifies the kinematics of electronics moving on out of those, interactions, which means you can better understand your classical differences in general, but you can also reduce your domino backgrounds
STFC-RAL-CR03 R61: So, if you don't in the background of an electron-neutrino interaction is a muon-neutrino neutral current angle,
STFC-RAL-CR03 R61: interaction, and so by, improving your separation of, neuron neutrino and electron neutrino, you can significantly reduce your, final-induced backgrounds to electrons. And we can again test… we can use these, sort of.
STFC-RAL-CR03 R61: summations of the materiality spectrum to better constrain, overall concept, and ultimately the systematic for our solutions.
STFC-RAL-CR03 R61: All of this, is of course for its own physics goals.
STFC-RAL-CR03 R61: But in an ideal world, we'd also, extend this to the next generation, which of course we can't do. So I've highlighted here, this is, again, that imperial energy spectrum, the second refers to the oscillation maxima, and the coverage of, the spectrum. This just goes to show that this cross-section measurements were neat.
STFC-RAL-CR03 R61: The constraints that we will, place on the models that we have will be applicable to you for that, which is, of course, I do.
STFC-RAL-CR03 R61: So moving on from certain interactions into the oscillation radiant.
STFC-RAL-CR03 R61: So, SBMD is the NID for the short-based Living Training Program, and in that role, it will have
STFC-RAL-CR03 R61: very, very little, sensitivity to any star… would have very little sensitivity to any sterile signal, which means we can simply use it to constrain those models, which I talked about already. And so that's… that's the power of SEOV in this, in this,
STFC-RAL-CR03 R61: SBM program. And in 2 out of 3 of these channels, SBM SEM is projected to have
STFC-RAL-CR03 R61: 5 sigma coverage of the previously explored phase space in the, spiral neutrino, parameter ranges. So the orange lines are 5 sigma, sorry, the solid orange lines are 5 sigma, and the orange lines are going to be small, and so we can see we're pumping back, out away from the allowed regions,
STFC-RAL-CR03 R61: quite, quite readily in both of these, muonutrino channels, and even in the electron-neutrino disappearance channel, which is unique to SPN to some extent,
STFC-RAL-CR03 R61: Particularly in the,
STFC-RAL-CR03 R61: short baseline program, we can even push, push out to the allowed regions at the 90% confidence level as well. So SBN is going to directly address the short baseline anomalies, and finally, I'm sure, I hope.
STFC-RAL-CR03 R61: finally, tell us what we need to know about steroids. Of course, microbrewing have made a pretty confident statement, we just need to put a pin in it now, in my opinion.
STFC-RAL-CR03 R61: Okay.
STFC-RAL-CR03 R61: And on the sort of nice, nice bonus side to SB&D, again, because of the detector technology, the location, and the performance of the photon detection system and the cosmic timing timing systems, we can also search for, beyond the timing model phenomenon as well. So just some of the examples of things we could potentially look for signatures of include dark neutrinos, the transition magnetic moment.
STFC-RAL-CR03 R61: Both of which are alternatives to the miniboom low energy excess, alternative theories, but you could also look for axion-like particles, heavy-dut leptons, Higgs vocal scalars, light dark matter, and merely charged particles as well. Some of these are ongoing searches, just before I move on to that, though, because it's kind of what they would look like in an SVMD simulation,
STFC-RAL-CR03 R61: Yeah, just to give you an idea.
STFC-RAL-CR03 R61: Some of these are under investigation already. We have a, we understand the model sensitivity paper in the works, but these are three, current sensitivities, just using Monte Carlo, in the dark photon, heavy neutral electron, and axion particle searches, so that's really exciting, and, I'm pretty sure we've got some data analyses, database analyses going on as well as the sensitivity paper.
STFC-RAL-CR03 R61: So… SBMD, started taking data two years ago, yep.
STFC-RAL-CR03 R61: But I… I was quite heavily involved in the construction of SB&D. I spent my LTA out there in 2018, so I was, I was mostly involved in the anode plane assembly construction, but this is same photo memory, so it gives you the idea. You can imagine the cathode sort of slicing the middle of the slice there, but you can see the effect of the anode planes, the sort of shear lines, and the photon detection system.
STFC-RAL-CR03 R61: So this, this was completed in 2022, and I… that was me in 2017. So that's the pit in 2017, and then in November 2022, the Cryostat was, completed in the near-deceptor hole, which was nicely timed, of course.
STFC-RAL-CR03 R61: Then, we have to transport the detector, so the,
STFC-RAL-CR03 R61: internal detector I showed you on the first slide, was constructed at the D070 building. It then had to be transported around the telephone ring, to the near detector hall, which they did very successfully, in December of 2022. So, September through December 2022 is a great time.
STFC-RAL-CR03 R61: Especially given the COVID situation at that point, it was all right, but not great.
STFC-RAL-CR03 R61: You then had to install the top half of the cardstock onto the,
STFC-RAL-CR03 R61: assembly transport fixture, I always have to wipe it down because I can never remember that. Yeah. So the top cap was… so we've got the choir stack, we've got the top cap ready, the detector's on its way, so effectively you attach the detector to the base of the top cap and lower it into the, the choir stack.
STFC-RAL-CR03 R61: So that was completed in March of 2023, and in April, that indeed was done. So this is a photo of it being loaded in, which is really cool. The resolution on here is not perfect, but, yeah,
STFC-RAL-CR03 R61: Yeah, so that was April 2023, the detector was, placed inside the choir staff. It was then… these aren't videos, because I…
STFC-RAL-CR03 R61: It's not upside down, for sure. I never assume I can show anything but a PDF, so I don't bother with videos, but in theory, there is a video, and you can see this is empty, and then this is the filled Lipper out online. So this is March 2024, so we've actually jumped a good year there,
STFC-RAL-CR03 R61: Don't ask me why, I can't quite remember. There'll be some reason, I think.
STFC-RAL-CR03 R61: And then after a bit
STFC-RAL-CR03 R61: like a rocky start. We've successfully ramped up to, high voltage in July of 2024, and you can see Ivella absolutely buzzing there. But that was, that was an interesting couple of months.
STFC-RAL-CR03 R61: So yeah, we finally, got our neutrinos in July, so these are our very first, recorded… well, some of our very first recorded neutrinos. So on the left, we've got a new ECC candidate, so you can see this is the long muon track, this is a little proton track. It's a lovely example of a candidate quasi-elastic interaction, because they're almost at 90 degrees from one another. So in an ideal world, it all looked like this. We could just say, yeah.
STFC-RAL-CR03 R61: That was a quasi-lastical interaction. No FSI happened. Here's some physics, but it doesn't work like that. Most of the time, they look like this. So this is, again, the muon.
STFC-RAL-CR03 R61: And then you've got some combination of, probably, possibly a proton.
STFC-RAL-CR03 R61: Possibly a charged pione's got a bit of a kink, so maybe that could have decayed to a mean one. And then because you have a distance from the neutron interaction vertex to these electromagnetic showers, we know that this was very likely to be one, if not two, neutral pions that have decayed to two photons. But that's the kind of thing that we're now trying to, like, you know, piece together, computationally.
STFC-RAL-CR03 R61: And I could have said all this in words. But yeah.
STFC-RAL-CR03 R61: What did I hypothesize? I wrote, I wrote this slide a while ago. So I reckoned it was, yeah, pretty much what I said. Most likely charge, charge resonance interaction with some combinations of protons and charged ions as the short contracts.
STFC-RAL-CR03 R61: So yeah, in short, the neutrino, as I've mentioned already, neutrino interactions with argon look really nice in our detector, but they're very, very tricky to interpret, particularly at the point that the physics of the neutrino have actually lost.
STFC-RAL-CR03 R61: So now, I've whizzed through this,
STFC-RAL-CR03 R61: This is kind of where we're at. I've managed to sort of corral all the latest talks I can find with all the public information. This is what we're up to. So this is how the detector is forming on the right-hand side. So the top is the electron lifetime as a function of, sort of, electrical time. The nominal is around 3 milliseconds.
STFC-RAL-CR03 R61: So not this, this dotted line here, this is what we've always quoted as nominal, but it's… Sorry, what's an electron lifetime? Right. So, you know how I said the electrons, drift towards the anode plane, so they…
STFC-RAL-CR03 R61: the charge ions, the electrons drift. The lifetime governs how many of them will be absorbed before they reach the alloy. So you want to maximize that lifetime to maximize your access terms of the electrons.
STFC-RAL-CR03 R61: So, yeah, nominal has always been 3 milliseconds, and that's kind of what governs the 2 meter, drift distance,
STFC-RAL-CR03 R61: Decision?
STFC-RAL-CR03 R61: But we are consistently exceeding 30 milliseconds, apart from the… but yeah, we're consistently exceeding 30 milliseconds. At one point, we thought it was close to infinite, which was really exciting, but not very realistic. But still, this will do, we are very happy with this performance. We've also, recorded, so protons on target is the way we measure, exactly how much beam has been delivered to the detector.
STFC-RAL-CR03 R61: So this is a recording of how much, how many protons on target we have had the opportunity to record, and how many we have recorded, and because the lines largely overlap.
STFC-RAL-CR03 R61: The collection efficiency is 98.6%, which is exceptional, and that basically means that when our shifters are on shift, if the DAC goes down, they restart it very, very fast. So, kudos to our shifters. We cleaned this up.
STFC-RAL-CR03 R61: I do shouldn't. And then the photon detection system and the cosmic ray tagging system are both,
STFC-RAL-CR03 R61: heavily involved in our timing reconstruction. And so, because you can see really clear peaks in these two blocks, what that means is we have, really fine granularity, at the nanosecond level, which means we can basically look
STFC-RAL-CR03 R61: every, every pulse of protons that enters, that produces neutrinos, we can look between those pulses for potential beyond the southern model, phenomena.
STFC-RAL-CR03 R61: So you can look, even at beam times.
STFC-RAL-CR03 R61: for non-beam activity between the timing buckets, which is really cool. But it also means that, in general, when we're reconstructing our, neutrinos, our T0 is really, really precise, which is ideal, and it's very, very good at cosmic rate tagging,
STFC-RAL-CR03 R61: Scenario for removing our downloaded background.
STFC-RAL-CR03 R61: And we have API for this as well. We've also recently demonstrated, set our sensitivity to low energy activity, so this is, the distribution, well, this is just with
STFC-RAL-CR03 R61: This will just be our, sort of, open data sample, which is really small, but this is demonstrating the reconstructed energy of Michel electrons, which are produced at the end of stopping me on track sometimes.
STFC-RAL-CR03 R61: And so they are, very, very low energy. You can see around the, sort of, tens of MeV range, which is very, very good that we can do for our electron searches. And you can also see really clear separation between our muons and our protons. So this is the energy deposited per unit length.
STFC-RAL-CR03 R61: Versus the residual range of the track, so… every hit…
STFC-RAL-CR03 R61: on the anode, that we record on the anode plane is some distance from the stopping point of the track, and that's known as the residual range. And so the smaller residual range, the closer you are to the stopping point, and
STFC-RAL-CR03 R61: stopping tracks characteristically, we call what we call the Bragg peak, which is a high, increase in the, energy depositions. But each particle, because of the mass differences, has characteristic stopping power, this distribution. And if you can separate those, you can separate your particles, you can perform, PID nice and computational, parallel physics. So this is an example of a separation between the meanwhile tract
STFC-RAL-CR03 R61: So that's really good. And what that means is that we can…
STFC-RAL-CR03 R61: record all the images, and we can also use them very well. It's all about being able to analyze these by eye, but coming to have 3 million of them per year, we really have to be able to nail this down in communication.
STFC-RAL-CR03 R61: Okay, yeah, so this is… this is my final slide. This is the list of, sort of, ongoing and near-future measurements that are underway right now. Our primary program is the cross-section program, as you can see. We have a bunch of these exclusive topological channels under investigation. Cc Inclusive always comes first.
STFC-RAL-CR03 R61: generally what is constructed that everybody else, carries on from. But we're looking at zero pi with one and two protons. These are characteristic of, the initial state, quasi-elastic interaction, and also, short-range correlations within the nucleus, which is the whole thing.
STFC-RAL-CR03 R61: One charged pione, one neutral pion, one eta, which decays to two photons in the same way as a neutral pion, but with a different invariant mass peak. But we are sensitive to eters, and so again, this could be good background rejection for our shower searches, and even coherent scattering.
STFC-RAL-CR03 R61: Scattering? Scattering. We're also looking at some neutral current measurements, which are often characteristically harder, because if you don't have your left arm to pinpoint the vertex.
STFC-RAL-CR03 R61: In the busyness of these event displays, it's quite difficult to,
STFC-RAL-CR03 R61: determine what's actually from a neutrino interaction, and what's just general noise or background. So neutral current interactions are very, very useful to, to get good at. And we're also looking into electron-neutrino inclusive, charge current inclusive, and one charge time as well.
STFC-RAL-CR03 R61: In the oscillation program, we have quite a few different measurements going on at the moment.
STFC-RAL-CR03 R61: Because of all the…
STFC-RAL-CR03 R61: characteristics of the detector I've discussed already. We've got a number of analyses ongoing that are performing the oscillation search with different channels, again, because of the increased ability to constrain the systematics with the near detector. So we have a standard new media appearance search with an inclusive, sample, so all the muon neutrinos that interact via the charge current.
STFC-RAL-CR03 R61: Which is the standard way of measuring these. But we also have a variety of measurements ongoing, which either look at just, 0 pi one protons, so you're looking for that really clean muon proton, because again, it's often very characteristic of a very simple topology, so it means you have,
STFC-RAL-CR03 R61: It means you can reconstruct your neutrino energy, with a sort of higher confidence level, but you can also separate into many of these different channels and fit them together to constrain multiple of the initial interaction possibilities at the near detector to then, again,
STFC-RAL-CR03 R61: Send off those systematic constraints to the file detector.
STFC-RAL-CR03 R61: We're also looking at NUI appearance with charge per inclusive, so that largely involves the bar detector. But again, at this point in time, we're focusing on, CC Inclusive, the NUI, but in theory, again, we could look at those exclusive channels.
STFC-RAL-CR03 R61: And in the not-too-distant future, it has been dabbled with at the sensitivity level in the simulation. We're also looking to put out a joint fit of, a new misappearance and a new reappearance search at the same time.
STFC-RAL-CR03 R61: Yeah, the sort of ultimate, sensitivity is sterile oscillation parameter spaces, space. And we're also looking into neutral current oscillation searches, which is, a whole other kettle of fish. We have one PhD student looking into this, and…
STFC-RAL-CR03 R61: It's in its reasonably early stages, but it should be quite an interesting study. And yeah, we have a whole BSM program, so I've already shown you the sensitivities of a few of these. The sensitivity paper is on its way out.
STFC-RAL-CR03 R61: And in parallel, they are also propagating through the blinding process in order to actually search for these things from data. So we have a lot of stuff going on.
STFC-RAL-CR03 R61: Can't show you an actual photo right now, but we will look forward to it.
STFC-RAL-CR03 R61: So yeah.
STFC-RAL-CR03 R61: That's pretty much everything for me. This is a really nice time to be on SBMD. But the… we have such a variety of physics techniques that students and myself can get involved in, that, of course.
STFC-RAL-CR03 R61: I was successful in this, but…
STFC-RAL-CR03 R61: sort of… it's like the younger sibling of the Micro family, but it's a really nice… it's a really nice collaboration. We took our first data in 2024, and it's looking really good, so everybody is really happy. It's a testament to a huge amount of work over the last 10 years.
STFC-RAL-CR03 R61: And of course, we're hoping that this will pave the way nicely for June. And I've listed all the measurements that are ongoing, and last year, Sheffield hosted their collaboration meeting, which was, absolutely lovely to show our collaboration October. So, yep, that's…
STFC-RAL-CR03 R61: Any questions or clarifications?
STFC-RAL-CR03 R61: Yes. Any questions?
STFC-RAL-CR03 R61: I probably explained it, but I didn't take any…
STFC-RAL-CR03 R61: What are you doing behind the nuclear cinema?
STFC-RAL-CR03 R61: No, wait, so wait…
STFC-RAL-CR03 R61: We're not doing things that microwave or not, we're working with IPRIS. Hmm, I know, but I mean, why do you need to develop a new detector? What's the role of the neo-detector? Okay, so the role of the near-detector is pretty much for constraining systematics. So if I go right back to…
STFC-RAL-CR03 R61: If we did not have a near detector in an oscillation search, you are fully relying on the model of your beam to tell you exactly how many muon neutrinos, electron neutrinos, etc. to expect. Simultaneously, you're also relying on that to constrain your sort of a model as well, but
STFC-RAL-CR03 R61: With the near detector, particularly a near detector with the same technology, you can use it to constrain… It's the… yeah, it's not… you were emphasizing the more modern sibling, and I wasn't sure… It's the more modern sibling that came online last.
STFC-RAL-CR03 R61: But yeah, so Icarus is all… Icarus also has a cross-section program. Icarus and Microbone are also sensitive to the NUMIB, which is the neutrino… I can't remember what it stands for. So they,
STFC-RAL-CR03 R61: They can do a holophysics program with a different beam. Microboom has its cross-section program. Microbone's sterile neutrino search was a joint fit between booster neutrino beam and newbie beam data, which was really interesting and unique. But SBMD, yes, is the new detector, in the BMB search.
STFC-RAL-CR03 R61: I mean, you're emphasizing the lifetime of the electrons, size the detector. You didn't talk about diffusion. I vaguely understood from Gasey's team that sees that without a magnetic field, the diffusion… Yeah, that's another reason for… so, like, I…
STFC-RAL-CR03 R61: Yeah, electron lifetime and diffusion are both, critical parameters we have to constrain, for sure. Again, because of the size of the detector, diffusion is affected… it's not zero by any stretch, but it's minimized because of that, that
STFC-RAL-CR03 R61: scale choice. So because they are only ever traveling a maximum of 2 meters, the diffusion isn't, huge, and you can, and the diffusion constants are controlling this part of the calibration program.
STFC-RAL-CR03 R61: So it is there. One of the things that, the calibration group are doing is group… you can group some of them, because they're 3mm separated, you can group some of the wires together to do, electro-lifetime measurements and see how many wires you have to group before things start,
STFC-RAL-CR03 R61: how few wires you have to group the book and start changing. So you can do quite a lot,
STFC-RAL-CR03 R61: to model the diffusion, and that's effectively what we do. We model it in straight and calibrate it, but it does have…
STFC-RAL-CR03 R61: So, actually, I had a similar question, but maybe just on that a little bit more. You quoted some numbers, and I could not quite remember what you… you said. I think you said you see a live time 30 microseconds.
STFC-RAL-CR03 R61: milliseconds, sorry. Yeah. What was your unpredicted one? No, no, no, sorry, we see above 30, the, I say the predicted, it's a bit of a legacy value, actually, but I suppose it was a design base. 3 millimeters… 3 milliseconds is the mini… is the…
STFC-RAL-CR03 R61: the minimum…
STFC-RAL-CR03 R61: have to be above 3 milliseconds in order to record enough electrons to do physics. And so anything above 3, and preferably towards infinity, is ideal. So the fact that we're at 10 times more than that consistently, it's great. It means we kind of
STFC-RAL-CR03 R61: We still met… haven't completed the plot, there's a very nice plot of it. We still measure the electron lifetime, routinely.
STFC-RAL-CR03 R61: Yeah.
STFC-RAL-CR03 R61: We still measure the electrolyte time, because it's a… it's a measure of the impurities in the detector, so the more impurities you have, the more electrons are within the,
STFC-RAL-CR03 R61: anoplanes, and that manifests as a reduction in the normal contract forward and therefore, a reduced lifetime. And what it means is you… sorry, I'm gonna talk amos in this life,
STFC-RAL-CR03 R61: it kind of means that the charge depositions you record at the anode, end up being higher than the charge depositions you record the cathode, because the ones that, initiate the start of the cathode capture the whole way across the detector, and so you effectively have a reduction in how much charge you record if you go down and further. And so ideally, that would flatten the difference, and so the electron lifetime… so this is your cathode, this is your anode.
STFC-RAL-CR03 R61: This is… the y-axis is also charge deposition. In an ideal world, you would have the same charge deposition, you're unaware, the electrons coming from the detector. As your lifetime goes down, it goes like this, and so you have to recover.
STFC-RAL-CR03 R61: artificially, the amount of water sector, and so we're sort of seeing a lifetime looks a bit like that, and nominal is like that. But minimal as that, we're seeing that in place that. So you were aiming at a minimum number, and what was your expected number?
STFC-RAL-CR03 R61: We don't really give an expectation. The minimum is set based on the systematic
STFC-RAL-CR03 R61: scale that that imposes. But the reason I'm asking is because in Dune, it ended up…
STFC-RAL-CR03 R61: being a lot longer than was originally anticipated. Yeah. So I'm just wondering how that matches with your original expectations and… Yeah, this is kind of what I meant. So, yeah, because of ProtoG, I think ProtoG gets around 35?
STFC-RAL-CR03 R61: it would take a lot more than… and as you say, it's a critical design parameter, so it could have got away with much bigger spaces. Yeah, so I think the nominal comes from the same era of the Dune nominal, at that 3 milliseconds, because again, it's in the design phase. So our expectation, because of the performance of ProtoDune.
STFC-RAL-CR03 R61: was that we can do better. Okay, so is that where you were using that for your… okay. Yeah, so the baseline is set based on the systematics we can allow, in the design phase, and…
STFC-RAL-CR03 R61: Yeah, so that just dictated the sort of size of the build. Okay, so your expectation wasn't to be caught production results, but that's where I was, that's where I was coming from. Okay, yes. In the original, timeline, SB&D and Prodo and SV were going to travel at the same time?
STFC-RAL-CR03 R61: I had a choice when I started my PhD. Okay.
STFC-RAL-CR03 R61: Made the right one. Sorry, that was a very long way of getting to this plot and explain that. Thank you.
STFC-RAL-CR03 R61: I don't have any other ones, I have another question.
STFC-RAL-CR03 R61: I was just wondering what was the…
STFC-RAL-CR03 R61: Oh, it's because they… they protect the pump, and then we've covered it, so…
STFC-RAL-CR03 R61: the purification system tripped, so lots of impurities came in. That's nice. I mean, that's a nice service. You might have done it on purpose, I don't actually know it, just to test it. Is it really explored, or should we just try and do it now and get it? I don't know if you can actually see it from the back, but there is a band that gives
STFC-RAL-CR03 R61: The time that the song, not drip only at about 30 minutes.
STFC-RAL-CR03 R61: Yeah, so you get something you want to mention.
STFC-RAL-CR03 R61: And I fit, the blue and the orange are the victims of disease. Sorry.
STFC-RAL-CR03 R61: I just think your detectors on its size, I mean, you wouldn't be tempted to remain relevant.
STFC-RAL-CR03 R61: We have to cut costs in so many… we were supposed to have an overburn. That didn't happen. No, I don't… I don't think we necessarily need the magnetic field.
STFC-RAL-CR03 R61: for the physics we want to do. I mean, yes, you could sort of separate your, intrinsic anti-nutrino, I suppose, by carbon in the electric field, but…
STFC-RAL-CR03 R61: Yeah, I don't think… I don't think it was ever in the design. I know the overburden was, and then had to be cut for reasons, but, yeah, I don't believe the magnitude was ever in there. And the building was constructed for the detector as well, so in theory they could have popped it in, but it was never… never a choice that they made.
STFC-RAL-CR03 R61: Okay, thank you for the nice thought. Is it okay if I ask two questions?
STFC-RAL-CR03 R61: So the first one is related to the prism that you did? Yep. Oh, yeah!
STFC-RAL-CR03 R61: Yeah, hi, hi, Ben.
STFC-RAL-CR03 R61: I should know more about this one.
STFC-RAL-CR03 R61: Please ask the question, not on the slide. It's rather simple, so I was just curious if, if SPMB uses, the same fitting method as
STFC-RAL-CR03 R61: So… I actually don't know. So the fitting groups, we use,
STFC-RAL-CR03 R61: I don't know, to be honest with you. We've not really collaborated.
STFC-RAL-CR03 R61: It's kind of on my to-do list, to be honest with you. But… Welcome to the junior, please.
STFC-RAL-CR03 R61: That's your next question. Okay, then I'll just ask my next question. The next question was, I was also curious, like, how do you reconstruct neutrino energy for a neutral current event?
STFC-RAL-CR03 R61: The neutrino energy is largely reconstructed. If it's not a nice, simple, quasi-elastic-like interaction, it's done with calorimetry.
STFC-RAL-CR03 R61: And then… For the neutrino. So what…
STFC-RAL-CR03 R61: What we probably wouldn't do for neutral current is use neutral energy as a parameter of the fit. We would use, harmonic theorematics. That would be my…
STFC-RAL-CR03 R61: choice.
STFC-RAL-CR03 R61: In terms of how we reconstruct the neutrino energy.
STFC-RAL-CR03 R61: Yeah, we would use hydraulic kinematics, and then some…
STFC-RAL-CR03 R61: I don't even think you could replace domestic energy, so I think you would just have to use a parameter that doesn't allow it.
STFC-RAL-CR03 R61: are some of the things that the hostage group is working on. It's looking at,
STFC-RAL-CR03 R61: Observable kinematics, rather than literature kinematics to best constrain things.
STFC-RAL-CR03 R61: I don't know about who elsewhere, my wife.
STFC-RAL-CR03 R61: Thank you, that makes sense.
STFC-RAL-CR03 R61: Yeah, I have another question about the prison bit of it. So, you know, you have your bins in these sort of, like, circular sections.
STFC-RAL-CR03 R61: It's a very vague question, but, you know, I was interested in, like, how that circle binning is chosen. It varies, actually. So this is one example, yeah. One of my PhD students… one of my PhD students looked into this as part of her oscillation search.
STFC-RAL-CR03 R61: So, you can choose the first of binning in two ways. One of them is constant statistics, one of them is constant angle, and so she's looked at how that choice impacts the sensitivity. And in general, because the statistics are so high, I'm a kind of work. Another consideration is that 8 bins
STFC-RAL-CR03 R61: is a lot computationally, and so she's looked at only 3 bins, and 5 bins, and 8 bins, and compared the sensitivity impact on that as well. So this was the… this was the sort of poster child for the PRISM regime of SVMD, which is the concentric circles with constant angle, but both these have very, very different areas, so you have very, very different statistics. So it depends… it depends on
STFC-RAL-CR03 R61: the search of doing with it, in my opinion. I would always say.
STFC-RAL-CR03 R61: Run a quick sensitivity check to see which
STFC-RAL-CR03 R61: which choice will suit you best for… I'm not sure why the 8th bin was chosen in the first place,
STFC-RAL-CR03 R61: there's probably some backing for that. Maybe it was some statistical,
STFC-RAL-CR03 R61: number that they set as a minimum. But yeah, we… you can… you can generally segment it however… however it suits best. Sorry, just to follow up, maybe, I was sort of thinking about it from the D perspective, right? The difference here, right, if you don't move it, then I guess you're relying on your vertex reconstruction to make sure that… Oh, yeah.
STFC-RAL-CR03 R61: I was wondering, like, what that resolution looks like, and maybe what systematic uncertainty she's thinking about, because I can imagine that events might have to move between bins if it's sort of, like, on those borders and whatnot. Yeah, so I've only looked at… we have only looked at this at the Monte Carlo, level at this point, and…
STFC-RAL-CR03 R61: So, before we do that, but
STFC-RAL-CR03 R61: the virtual… I think she ended up putting, like, an assumed vertex resolution, it wasn't actually being as part of, so I can't really put a number one. One other thing we have considered, sorry, just to your first point,
STFC-RAL-CR03 R61: like I've mentioned a few times, you can… you can define these segments in such a way that you actually isolate the Icarus.
STFC-RAL-CR03 R61: frontbakes, effectively, and so we… you can define an angular distribution, or an angular component that effectively reconstructs the Icarus neutrino energy spectrum, which is super useful, because then you can sort of, like, use the rest of the SBMD detector as,
STFC-RAL-CR03 R61: another, sort of, almost another detector, then you know you have all this one-to-one mapping between, your energy distribution in both places. You can play around with it,
STFC-RAL-CR03 R61: statistically, at least.
STFC-RAL-CR03 R61: What happened with the ramp up? You had a bit of history, and you sort of alluded to it.
STFC-RAL-CR03 R61: What can you call it? Sunset box. It was just…
STFC-RAL-CR03 R61: There was a moment they got partway up the ramp up, you're actually saying this. They got partway up the ramp up, and everything…
STFC-RAL-CR03 R61: the… the… the… The protector literally looked like a sunset, and it was…
STFC-RAL-CR03 R61: just terrifying, so we stopped it for a while. And this was just the Bundy tree in 2024 as well, give it some remembers. And what they ended up doing was just going, just power through, carried on, and it all played out.
STFC-RAL-CR03 R61: I don't know what the cause was, I don't know if they've sussed it out, I'm sure they must have done that, but two years down the line, it's been fine. So yeah, it was… they called it Santa, I can't remember…
STFC-RAL-CR03 R61: It was like, you can imagine the two youth folks,
STFC-RAL-CR03 R61: I don't know, some massive amount of electronics noise going on.
STFC-RAL-CR03 R61: wage distribution.
STFC-RAL-CR03 R61: visit.
STFC-RAL-CR03 R61: Yeah, so, you preferred to your overburn, earlier in the absence of it, and you've got a cosmic, veto, so I was wondering how much of an
STFC-RAL-CR03 R61: impact cosmics have. So you're able to identify them and remove them, but does it lead to… Space shock. …any amounts of…
STFC-RAL-CR03 R61: set times, and…
STFC-RAL-CR03 R61: It's not so much dead time, it's… it's pretty much space charge. Thankfully, because microgron and Icarus are both sort of before us, we've got, the methods of, sort of, prioritizing space charge down pretty well. We can kind of adopt their methods, obviously, you have to prioritize itself in this, in the detector of interest, but, yeah, what it effectively means is,
STFC-RAL-CR03 R61: Because you have…
STFC-RAL-CR03 R61: so many cosmics, traveling through the detector in one go, ionizing the argon, you can end up with an excess of ions that drift towards the cathode, which fires your electric field, and end up shifting the charge deposition, distributions as well. And so that, that is, what was the map.
STFC-RAL-CR03 R61: And, effectively matrix that you can… Yeah, calibrates out, effectively.
STFC-RAL-CR03 R61: But that is the impact. It's… it's… Okay. So you're not… you don't have any dead regions or anything, or dead time, you've just got to calibrate for it? Okay.
STFC-RAL-CR03 R61: It's another reason why the CRT is super helpful. Yeah, I love them. And, and even…
STFC-RAL-CR03 R61: where the actual… I don't know what the density ends up being.
STFC-RAL-CR03 R61: We don't have to declare any dead region around a particular track? No, no, we don't,
STFC-RAL-CR03 R61: No, we just slice up the reconstruction into regions of interest to try and remove them, but you don't have to,
STFC-RAL-CR03 R61: you don't have to declare anything like that. I mean, it's, of course going to be harder to reconstruct something that's very, very simultaneous or overlapping, but the detector's generally large enough. And the neutrino, of course, neutrinos coming in along the Z direction.
STFC-RAL-CR03 R61: break down, and because of the elephants, not many of the meals are upwards. So there's… there's a reasonable ability to, get into a region, from public regions.
STFC-RAL-CR03 R61: So, on your, VSM page, which was… Okay, so you whisk past it at a high speed. Yeah, I couldn't tell, yeah.
STFC-RAL-CR03 R61: Yeah, okay, so maybe start on previous one. So this was really nice, but I, I just wondered, maybe you've got
STFC-RAL-CR03 R61: some…
STFC-RAL-CR03 R61: examples of how you differentiate such signals. Oh, yeah, this is partly why I included the event displays. So you can kind of see that largely, most of them result in some configuration of an electromagnetic shower. I think what you would end up doing
STFC-RAL-CR03 R61: This is me fully hypothesizing I've never attended the other.
STFC-RAL-CR03 R61: My hypothesis would be that these would have characteristic energy, invariant masses, or,
STFC-RAL-CR03 R61: Something like that, that you could then characterize as each one of these scenarios, based on the topological
STFC-RAL-CR03 R61: Appearance in the detector, and the, hypothesized energy,
STFC-RAL-CR03 R61: So your, your dark neutrinos and your axion-like particle, you're, you're using an invariant mass separation? Yes, well, I would.
STFC-RAL-CR03 R61: To me, it's two photons reconstruct two electrons, yeah, and especially because they do look… you've got a vertex, you've got two showers, and again, you'll have, you know, depending on the energy, you'll have some expectation of the angular separation to boost
STFC-RAL-CR03 R61: And is the group that's working on this BSM stuff
STFC-RAL-CR03 R61: Also working with you in prison?
STFC-RAL-CR03 R61: Guys for BSN potential. I don't know, actually. The main…
STFC-RAL-CR03 R61: people, like, so… the main groups, I think, are UCS Bailey, And… For none…
STFC-RAL-CR03 R61: And I don't know if either of us are involved in… If you go to the other slide, Pedro, which I don't exactly has done work.
STFC-RAL-CR03 R61: Sorry, this one. Yeah.
STFC-RAL-CR03 R61: Yeah, he's been on all of it, I believe. Sorry, I think there was a Genesis version going into BSF. Oh, really? Yeah.
STFC-RAL-CR03 R61: Minnesota.
STFC-RAL-CR03 R61: Okay, thanks.
STFC-RAL-CR03 R61: I actually haven't updated these links in a little while, so they've been instantly reduced ones. But yeah, there are some notes I'm excited for next week.
STFC-RAL-CR03 R61: Excellent.
STFC-RAL-CR03 R61: Yes, that was a very nice talk. I don't see questions.
STFC-RAL-CR03 R61: But we will head to lunch, so if you would like to speak with Riano, please join us.
STFC-RAL-CR03 R61: And let's think of, okay.
STFC-RAL-CR03 R61: I want to be going to shut down.