STFC-RAL-CR03 R61: Yes.
STFC-RAL-CR03 R61: previous projects which you're all involved with, so it's a certain library for me to be involved with. Right, and so this is about double chamber, data.
STFC-RAL-CR03 R61: not the kind of double chamber data that you might go to the PDG or some of the paper and go and look up, but really the raw, absolute raw data, which in these days, on the days of double chamber experiments, we call it a photographic film. So I'm going to talk about,
STFC-RAL-CR03 R61: you know, what would start off, for those of you who aren't familiar with the double chair, which was me a few years ago.
STFC-RAL-CR03 R61: what they are, how the data were recorded in the experiments in those days, why I've come to become the custodian of some of this data, and why what I'm doing to try to share that with the rest of the world.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: Very quickly, the bubble chamber is basically a particle detector, charged particle detector, embedded in the 55 cap called Don Glaser. Basically, the operating principle is very simple. You basically hold a volume of transparent liquid close to its warning points, and then you suddenly expand the volume
STFC-RAL-CR03 R61: And then you basically have the liquid in the superheated phase, and when charged particles pass through and analyze the liquid.
STFC-RAL-CR03 R61: And they form little bubbles, the nucleation points, and they basically have a trade bubble along the track, and this basically gives you a picture of the trajectory of the charged particles through your chamber. So it's a remarkably simple detector.
STFC-RAL-CR03 R61: Which gives you direct, visible information of the trajectory of a trip particle, so it's a terrific. And of course, Robert Shames went on to do all kinds of great stuff for the hypothetics field.
STFC-RAL-CR03 R61: We'll talk a bit about that. But how do you particle physics with Hubble chambers? Well, it's basically very simple. You have, you know, to all intents and purposes, your Hubble chamber is almost everything you need to do an experiment, apart from a beam, of course. But in order to record the data, you need some sets of, cameras to,
STFC-RAL-CR03 R61: basically take a picture of the… what's going on inside the bubble chamber. The details of how that was done there a bit later, but basically you have some flash lamps to illuminate the chamber, some excessive cameras to basically detect the lights, and whether or not the light is… you're looking for the shadows of bubbles, or the light tree bubbles, depending
STFC-RAL-CR03 R61: on the,
STFC-RAL-CR03 R61: the details of the chamber, but basically we have some way to record these trails in the chamber. We also, of course, have a magnetic field, to give some momentum-dependent collection of the particles.
STFC-RAL-CR03 R61: And basically, you would synchronize the, the, the photographic, the flash with the photographic, flash lamp, then the, the exposure of the cameras.
STFC-RAL-CR03 R61: with the timing structure of your beam, and then basically you have a typical fixed target experiment where the bubble chamber of the liquids in that bubble chamber is serving both as the active medium of the detector, but also as the target. So it's remarkably evident
STFC-RAL-CR03 R61: Which is my perspective. And, very simple,
STFC-RAL-CR03 R61: Yeah, things to do. So basically, these chambers are often filled with liquid hydrogen, because this is the simplest, it's also… this simplifies the interpretation of what's going on, so it's basically your beam on a proton, but also because it minimizes the mortal scratching. Then later, as we'll see a bit, some later chambers use very heavy,
STFC-RAL-CR03 R61: liquids are just a very rare process to go to increase the cross-section. Things like, freedom, the nasty things that we use at the end of the heavy liquid chamber. This is, in a nutshell, what a bubble chamber experiment is. Hopefully, some of you, well, I'm sure you've been exposed to what these things are before, and so, just to give you… that's what we're doing today.
STFC-RAL-CR03 R61: Right, and so why article does its, book shame is so fun and so intuitive? Well, this is an example of a charmed,
STFC-RAL-CR03 R61: So, Neutron Neutrino Bay, this is the big UV in the public chamber.
STFC-RAL-CR03 R61: This is, a, I think it's a liquid hydrogen chamber. We truly have been coming in
STFC-RAL-CR03 R61: scattering up protons to make a charmed, meson. So this is in the era when charm was being discovered in charmonium, in the… in the late 70s, but the charmed hydrons, so things like the mesons, as we call them now, weren't well established, and people, you know, didn't believe that they were… I understand, people didn't believe that these things really existed, until you would see them in the bubble chamber.
STFC-RAL-CR03 R61: image, rather than looking at mass piece and so on, because you basically can see an unambiguous, picture of everything that's going on in the event. There's no loss of acceptance, there's no loss of efficiency in the tracks. You can literally see every single charge possible that was made in the event, and work out, by various means what they… what species they were.
STFC-RAL-CR03 R61: So you can work out that this was a K-on, because of the fact that it's a slow km, but because of the ionization profile, and then the fact that this K-on interacted again with the chamber to produce a sigma, which then decayed… so this can be an ambiguously be identified as K-on. You can tell this is a pine, because then it decayed itself into a muon and electron.
STFC-RAL-CR03 R61: And all of this, basically, the decay chain can be unambigiously worked out, and in this particular event was one of the candidates for the DSTAR production neutrino, scattering, and this is one of the pieces of evidence that people really believe that these are… these charms tablons are there, and that what they were seeing in the mass piece was one that was genuine.
STFC-RAL-CR03 R61: So, this is an example of why double chain would be such a great tool in particle physics.
STFC-RAL-CR03 R61: Right, and so, you know, I don't need me to tell you that Paul Chamber had a great impact on the field in the mid-20th century, so here's just a few things that it did for the field. So the understanding of the light hadron space, this is probably the most, you know, what people tend to remember it for, that the whole zoo of particles that was, of hadrons in the
STFC-RAL-CR03 R61: And it, like, essentially, was worked out and done…
STFC-RAL-CR03 R61: together with a collaboration with the food, community worked out the model for, C3, and so on for this result, and with the US and CERN chambers, particularly the Berkshire Chamber, and the Arthur group.
STFC-RAL-CR03 R61: Then, later on, leveraged the neutral, weak neutral current from, card mill, then the gear from both, which handled lots of things, PC effects, and I saw it, nutrients.
STFC-RAL-CR03 R61: So there's loads of stuff that was done, public chambers, and it really transformed the field in the mid-20th centuries.
STFC-RAL-CR03 R61: Here's, again, another nice example of how terrific these things are. This is the famous event at Brookhaven, where the Yoga Barrion was identified from a single event. So, because of the
STFC-RAL-CR03 R61: You know, the unambiguous nature of what you're seeing there, you could, you know, claim the discovery of a path of a single event, and this is probably your view nowadays, but, you know, it's the kind of thing which is possible due to the, you know, terrific features that we've developed.
STFC-RAL-CR03 R61: Right, so I'll say a few things about why me as somebody from Birmingham came to be involved in this. So, all the chambers in Birmingham have had a relationship going back right to the beginning of the year.
STFC-RAL-CR03 R61: use. So, many of you may know that it… well, maybe not, but in University of Berlin posted a 1GB proton synchron, not the QB MC4040AV cytopron that was mentioned a moment ago. This is,
STFC-RAL-CR03 R61: synchrotron, which was actually the highest energy power accelerator in the UK for a long time, until the new mod accelerator at Wild was built in the 60s. So, this was… this was a great thing to have at the university, and it was equipped with a bubble chamber.
STFC-RAL-CR03 R61: So right from the, late 50s and early 60s, it was a bubble-chambered team in Birmingham who were trying to exploit the accelerator that was there. And then later on, as this thing wound down in the early 60s, because it was quickly superseded by the Bevatron at Berkeley, and then later the Limod City as well.
STFC-RAL-CR03 R61: The experiments here, we see spin and bear, as with a lot of the fields, they moved certain into the big national labs. So Birmingham was still very much involved with bubble chamber, particularly data analysis at this point, and, in the late 1960s became very much involved in this two-meter bubble chamber experiments, which I'm going to discuss a lot about today.
STFC-RAL-CR03 R61: So this is an extract from Mel.
STFC-RAL-CR03 R61: a, conference proceedings celebrating the bubble chamber did for the field. And you can see, this is, basically looking at the history of the data that was, analyzed in Birmingham.
STFC-RAL-CR03 R61: double chamber data, and you can see lots of entries from the two-meter bubble chamber at CERN. But first, the thing that I find most striking about this is the raw amount of person energy that was invested into this.
STFC-RAL-CR03 R61: This is a graph showing you the full-time equivalent, person power that was invested to analyze the data. It's basically looking mindfully at the pictures, and you can see that at the peak around 1975 or so, there was 40 people that could have been working on this environment, analyzing data from all kinds of
STFC-RAL-CR03 R61: places from… from those posted demographics, rather.
STFC-RAL-CR03 R61: Later on, it burns up in Slack, too.
STFC-RAL-CR03 R61: And then there's one particular, experiment that we focus on, this, 8.2 GBK minus experiment, where there was up to, you know, there was several million, so 1.5 million pictures were just analyzed in here. So this is…
STFC-RAL-CR03 R61: Now you see where I'm going here. There is lots and lots of double chamber activity in film flowing through Birmingham.
STFC-RAL-CR03 R61: And lots of, yeah, lots of activity. So, it's… which you'll be not surprised to hear, remember, but, there's tons of this stuff still in Birming.
STFC-RAL-CR03 R61: lots of photographic film from these experiments, in particular lots of film from the CERM genie published. We'll talk about that in a second. So,
STFC-RAL-CR03 R61: There are around 50 teams at this environment. I'm sure there's plenty of this around at other UK institutes, and I became captivated by this, not because of the terrific and really interesting features of the local Chamberg feminist himself.
STFC-RAL-CR03 R61: but also how good the condition is that we… the film we have in Birmingham is. So, maybe some of you know that photographic film of this era decays very quickly just due to the
STFC-RAL-CR03 R61: oxalization in the air by this nasty, process known as vinegar syndrome, where basically it decays and not giving off the vinegary smell due to the chemistry of what's going on. But because our stuff has been kept in very cool environment, in the tins for a long, long time, it's in terrific condition, and all of the… you'll see, like.
STFC-RAL-CR03 R61: It's remarkable.
STFC-RAL-CR03 R61: And furthermore, we have… we'll see why this is relevant in a moment. Most of this is complete, in that it has data from all of the views with which the chamber was, photographed. We'll see why that…
STFC-RAL-CR03 R61: So, it struck me that this is a really remarkable result, historical asset, and also particle physics result.
STFC-RAL-CR03 R61: that needs to be preserved, because there's great risk of this just being lost. This was sold in public that, you know, who knows what could have happened to it. And, so that what we're going to talk about here is trying to see if we can do something useful with this, and at the very least preserve it for certain generations, too.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: I'll quickly talk about the CERN Digital Defender, because that's where most of this data came from. So this operated between 1964 and 1977. It was basically… it's one of the leading global chambers of the era.
STFC-RAL-CR03 R61: It was fed via the proton symphon, which had a proton beam of up to 25 GB, and had an RF-separated beam capability to provide the chamber with a whole host of different elements, so protons, protons, pions, and pions. And this will actually provide millions of pictures, which is unprecedented for the time throughout the decade.
STFC-RAL-CR03 R61: it's probably not well remembered in the community, since it didn't lead to any direct discoveries, but it was really the workhorse of the several chambers.
STFC-RAL-CR03 R61: Thanks for me.
STFC-RAL-CR03 R61: You mentioned that most of the film was destroyed once the experiment was completed, but that means scanned, so you've still got the scanned data, and is that sufficient, or would you really need to go back to look at the film if you wanted to do something? So we can talk about that a bit later, but I suppose it limits what you… what you're able to do. You're relying on
STFC-RAL-CR03 R61: Yeah, like, on the analysis at the time. But yeah, so we… all of the…
STFC-RAL-CR03 R61: The summarization can still exist in some format, but the raw film is the long one, just using the boiling it.
STFC-RAL-CR03 R61: Brilliant. So… Robin.
STFC-RAL-CR03 R61: So this, in particular, this is the frame which we have a lot of. We have around, 30 tins of this stuff, so around, 10,000, film frames.
STFC-RAL-CR03 R61: This was an 8.2GB, K-on beam experiment, which was designed, to study, search for new catalogic residents, in particular study the, which at the time, there was only a handful of candidates around, and this was trying to get more candidates in order to measure slightly more precisely.
STFC-RAL-CR03 R61: This is one of the final experiments of the checkbook.
STFC-RAL-CR03 R61: It led to, quite a lot of papers, but this is just to set the scene of what. So this is a quite high-energy KMV, going into a liquid hydrogen project.
STFC-RAL-CR03 R61: So, my thoughts about this is that, it's now, you know, fairly common for, you know, video, audio recordings, photographs, all kinds of other scientific or historical records, even, you know, astronomical data to preserve posterity by digitization.
STFC-RAL-CR03 R61: So could we do something similar here, where we've got lots of this, double chamber double chamber build, which people of my generation have no idea about at all? Could we try to, you know, at least preserve it for posterity?
STFC-RAL-CR03 R61: Make sure people are aware of the kind of great stuff that was done back in this era, or further still try to get some physics back out of it, at least as a hydrological dissolve.
STFC-RAL-CR03 R61: So, basically, that's the whole idea here, is how we build some kind of set of hardware, maybe some accompanying software, to digitize all of this film, which is this, like I said, there's tens of thousands of frames here.
STFC-RAL-CR03 R61: on a practical timescale, and then basically put it on the internet for somebody to use or do something fun with. And then we should also do it in a way which is sensitive to the, kind of, the precision that these things were done with at the time.
STFC-RAL-CR03 R61: And retain the possibility of, future scientific exploitation against the fighter.
STFC-RAL-CR03 R61: repeat the analysis of this in some way. So that's the idea. So that's what I'm going to try to set out today, is… this is a kind of fun project that, I got involved… I started to… to do for some reason. And, yeah, so I'm going to try to preserve this, and I'll tell you how we did.
STFC-RAL-CR03 R61: So, just to kind of see this, the actual photographic film is this highly kind of triastates surface. This is a durable, non-parample film. This is good because some of the earlier films were flammable, and they had a different, surf effect, which graduated much faster, so…
STFC-RAL-CR03 R61: This is of the era which, you know, is a pretty robust film and not so dangerous, but some of the earlier stuff is long gone now of, you know, quite dangerous, kind of research. That's not so much the case with this list.
STFC-RAL-CR03 R61: Each of the, these films, these tins that you see contains three rolls of film. Each of these, rolls of film correspond to a different camera viewing your chamber. We'll talk about why that's important for a moment.
STFC-RAL-CR03 R61: And then the film itself is in this very obscure format, around 50mm long. Each frame is around 170mm long.
STFC-RAL-CR03 R61: But the frame advance varied frame to frame, so, you know, people probably remember when you used to take a photo with your film camera, you'd have to roll it back, you know, wind the film on. The amount by which that is rolled on at the 72 meter chamber was varied, so you can never tell frame to frame how much you've over advanced the film, so…
STFC-RAL-CR03 R61: Look to the next framework for them.
STFC-RAL-CR03 R61: But, in summary, this is the kind of stuff that we've got the list of things that you've got.
STFC-RAL-CR03 R61: So, the… the whole…
STFC-RAL-CR03 R61: let's say the ultimate goal here, which might just be pie in the sky, was to try to see if we could get some… do some analysis of this data again. So in order to do so, we need to make sure that we can digitize this data in a manner that we can actually resolve the tracks and do a pretty good job of
STFC-RAL-CR03 R61: Preserving the, the really great information which was there at the time, and led to a lot of the great work that was done.
STFC-RAL-CR03 R61: In that era. So what we need to be able to do is, at least for the digital resolution that we're going to sample this image, make sure that the tracks in the chamber that we can see in the images are sampled by several pixels, so that we can actually work out the centroid of the track when we do our analysis later on.
STFC-RAL-CR03 R61: So this is kind of analysis, what we do in, silicon detectors and strips and pixels by looking at the center of gravity of the cluster on a multi-portrait end where you're looking at the, you know, looking at different wires and see how the charge is collected. If we… along with it, wires. So if we can basically look at the pixel intensity
STFC-RAL-CR03 R61: of the image along a few different pixels, we can work out the centroid by the relative weight. So basically, what we need to do is make sure, that the digital resolution that we synchtise with is commensurate with the
STFC-RAL-CR03 R61: The full width half maximum of the intensity profile on the handle on the film. So the full width half maximum of the tracks on the film is around 40 micron on the film.
STFC-RAL-CR03 R61: So we need to basically make sure that every track is sampled by at least 2 or 3 pixels.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: assuming that we can set the optics up so that we won't release it via that resolution, we need a sampling scale of at least 13 micron per pixel or lower, so basically we need to, you know, do justice to the intrinsic resolution of the nice,
STFC-RAL-CR03 R61: So remember, this is the number 13 icon that picture that we're trying to achieve.
STFC-RAL-CR03 R61: So, how do we do this, then? So,
STFC-RAL-CR03 R61: You know, the contemporary methods that people analyze the film with typically involve projecting the film onto a big screen that then people could look at, or measure, or…
STFC-RAL-CR03 R61: do other things. I think the film was also directly measured itself, for example, with a microscope. I'm not sure that was… that was too common. But basically, on taxable grounds, for this particular endeavour.
STFC-RAL-CR03 R61: We don't have a lot of space, we don't have a lot of money, we don't have a lot of time, so we want to try to keep it clean as practically motivated as possible, keep it simple, keep it small. Therefore, we're going to try to directly image the film with a digital camera, do the screen as simply as that. So, what we technically need to complete to get to this 30 micron pixel.
STFC-RAL-CR03 R61: So, we need to work out how can we achieve that with, basically, a camera, a lens, putting the film at some distance and illuminating it.
STFC-RAL-CR03 R61: So it turns out that typical imaging sensors have got this 4-3 format, which is a bit awkward given the format of the film, which you can see has got this, you know, showing much longer than it is, whole.
STFC-RAL-CR03 R61: So, we're limited by the long axis of the sensor, so we need to make sure that we can fit this 120… the image of this 120mm long piece of film onto all of our long… long way of our sensor.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: In order to achieve this times this gives you 5,700 pixels, so we basically need to find a sensor that can give us that many pixels, and we basically, yeah, we would do the math, you basically need to make sure that the sensor, the size of the, the image of the film on the sensor
STFC-RAL-CR03 R61: It's 23mm wide, so I'll work out. So, you then need to work out how you're going to do this in practice. You need to basically put the film at some distance from the lens, work out the appropriate focal length of the lens, make sure that it's not going to limit the final attraction.
STFC-RAL-CR03 R61: And also realize that some lenses don't focus too close and all kinds of things. But with some, balancing with all the relevant constraints.
STFC-RAL-CR03 R61: with one of the so-called full-frame sensors, which is the kind of thing you find in a fancy digital camera, an 18mm focal length lens, a few centimeters away from the film, we could achieve all this in principle. So, but it seems like it couldn't work.
STFC-RAL-CR03 R61: So, let's go try and build this. So, this is a kind of cartoon of showing you roughly what I'm trying to say. We have our camera here, so camera lens.
STFC-RAL-CR03 R61: And then film. And basically, you have the film attached to some mechanism to advance it, and we literally just take a photo of the film while it's illuminated from that. So it's the most simple thing you could ever imagine.
STFC-RAL-CR03 R61: Let's see how… how far we can get.
STFC-RAL-CR03 R61: I'm going to be outside of that.
STFC-RAL-CR03 R61: So this is… this is it in practice. I got some funding from the Royal Society and the SCSE In Practice Federation account to build this thing, so if somebody believed that it was worth doing, you can tell me later. But anyway, this is what we built. This is basically showing you… this is a reader film, this is a box closing all… keeping it all dark.
STFC-RAL-CR03 R61: Then you can see the bits and pieces inside, so you can see the camera, the lens, some void, then the film realm being credited to some clean literary types and feet,
STFC-RAL-CR03 R61: heading in the right direction, and then some illuminated panel to show space, so we can actually see the image. That's what it looks like. Built this a couple of years ago, and it took a long time to get working.
STFC-RAL-CR03 R61: Adequately, but it now works, and it's working very well.
STFC-RAL-CR03 R61: So I'll say a bit more about the technical details for those sensors. This is actually… this camera is actually intended for us to run astronomical imaging, so it's one of these full-frame sensors, it's got a very high pixel density, 16-bit sensitivity, so it's a whole, you know, very, very nice, camera.
STFC-RAL-CR03 R61: There's a UV locking built in.
STFC-RAL-CR03 R61: In place as well. Then we have the lens. It's a very high quality, very low distortion lens, intended for machine vision applications, so things like when you're monitoring production lines or wanting to do some kind of quantitative analysis of an image, you want to have low distortions, optical distortions.
STFC-RAL-CR03 R61: This is what these things are designed to do. This gives us our equivalent of 380mm, and, we operate it, so it's fairly big. This is placed around 35cm from the,
STFC-RAL-CR03 R61: So that's how it works.
STFC-RAL-CR03 R61: Then, to illuminate the film from behind, we have this space, this panel here, which is, a diffused, piece of plastic with, something called an electromrescent panel. It's basically just a light panel, which gives very high, uniformity, light,
STFC-RAL-CR03 R61: it basically just… light distribution spatially is uniform. We use blue light just to match the pumping efficiency of the sensor.
STFC-RAL-CR03 R61: And also to try to eliminate, some of the comments separation from that being blocked if we get to use them.
STFC-RAL-CR03 R61: So, narrower range of them.
STFC-RAL-CR03 R61: Of light, in terms of wavelength.
STFC-RAL-CR03 R61: That's how we note it, but in terms of the film piece, this is kind of not a great picture, but you can see roughly what's going on here. This is a motor rotation stage, which basically pulls the film through some system of,
STFC-RAL-CR03 R61: guides. The film is kept hot, very, you know, inside this rotor so that it's flat. We'll see why that's important in a moment. And, yeah, there's various bits and pieces to it for practical reasons, but basically that's… So, the idea is that we have some automatic system
STFC-RAL-CR03 R61: Where we can advance the film, take a photo, advance again, keep going, and this can be left unattended, because it's going to take an awfully long time to digitize the 10,000, you know, library, frame library of the film, if you want to do anything mutual a little bit of that.
STFC-RAL-CR03 R61: That's… that was the idea.
STFC-RAL-CR03 R61: Then, of course, it's got a optically, yeah, enclosed watch to make sure there's no spray lines, so…
STFC-RAL-CR03 R61: He's alive.
STFC-RAL-CR03 R61: Right, so then we have to write some software to do this. I won't really top-up, this is not very interesting, but basically it just…
STFC-RAL-CR03 R61: you just have to advance the film, take a photo, and so on. But the massive part of it is that I mentioned this, but this film advance wasn't, you know, an equal
STFC-RAL-CR03 R61: if it's equal…
STFC-RAL-CR03 R61: advance of the film on the actual video. So, it would be okay, to make sense if you were just dealing with a
STFC-RAL-CR03 R61: knew that, but you don't know it. So what you have to do is, in real time.
STFC-RAL-CR03 R61: work out where your frame is, and align it so that you're not having the film moving around all the time. Because if you start accumulating errors after about 10 frames, you're totally lost where you are in it. So this is a bit of my…
STFC-RAL-CR03 R61: So we have the data stream in real time, take a photo, use some… some data analysis to work out, is it in the right place? If not, move it, carry on, and take the data.
STFC-RAL-CR03 R61: So, in this way, because I'm not such a, you know, I'm only one person, it takes around 12 seconds to do one frame, which is pretty good. So, most of that time is the computer thinking about the
STFC-RAL-CR03 R61: And the data analysis, and also the exposure time of about 2 seconds or so.
STFC-RAL-CR03 R61: No, it should look at the White House.
STFC-RAL-CR03 R61: The trigger bit… I don't… how fast were the one trigger photos? About 1Hz or so.
STFC-RAL-CR03 R61: So it's… Faster than that, at least. Well, no, not starter than that, but… yeah.
STFC-RAL-CR03 R61: Yay.
STFC-RAL-CR03 R61: So, yeah, we can do one thing in about 3 hours, which is practical, so I can set it going and go out and do whatever else I need to. So that works.
STFC-RAL-CR03 R61: So now, now that we've built it, what kind of problems did we manage to achieve? So we managed to achieve, our, proposal.
STFC-RAL-CR03 R61: We've actually got about 17 bits in the end, with anybody kind of zooming in a bit and chopping off some of the information which is here, which, given that we're interested in maybe what's going on here, and there's just a timestamp in it.
STFC-RAL-CR03 R61: So we get our 17 micron pixels, so basically every track is sampled by around 3 to 5 pixels. This doesn't do it justice, because it is all the, you know, the way that my computer showed inside.
STFC-RAL-CR03 R61: You can begin to appreciate that, actually.
STFC-RAL-CR03 R61: But take my word for it, each crack is sampled by around 3 to 5 pixels, depending on the orientation, which is very… certainly enough to basically determine the difference between an environment and as a track where you see individual bubbles, so this is an individual bubble.
STFC-RAL-CR03 R61: Yeah, and this is very highly analyzing possible, maybe FOC proton, where you can see it's all just sort of thick, very dense ionization time, because of the FO5.
STFC-RAL-CR03 R61: You can also work… see very small displacements, to, separately positive. You can basically do everything you wanted to do at the time, in terms of the analysis by,
STFC-RAL-CR03 R61: with the data, in the manner that we managed to do that. So, that's good. The, the image depth, because we have this 16-bit sensor, is, very granular, so we can tell the difference between, you can do this centrally very well.
STFC-RAL-CR03 R61: And it's all… it's all pretty good. The problem is, it generates a lot of data, so this is now 30 megabytes per image.
STFC-RAL-CR03 R61: there's 3 views, and there's 10,000, so it's many terabytes of data. It's just its own problem. But, anyway, that's, so, this works.
STFC-RAL-CR03 R61: So, you can, go and have a look at these at your leisure. So, basically, we have a… there's a website, bookmarkhamber.web.so.ca, so checklist website tells you more about the project. If you click on Image Viewer, I'll very quickly show this.
STFC-RAL-CR03 R61: Now, so you can see what is going on, if you… this is the website, if you go to here, Image Viewer, you can basically go and browse the images at your leisure and see what's going on. Take a look, look at the different views, which will pop up at in the moment.
STFC-RAL-CR03 R61: magnify them.
STFC-RAL-CR03 R61: All kinds of things. So it's, hopefully quite fun for those of you who are interested in
STFC-RAL-CR03 R61: So,
STFC-RAL-CR03 R61: So that achieves the first goal of at least preserving it to the prosperity, and exposing people of my generation younger who weren't… who don't really… weren't taught about bubble chambers at school or anything like that at all.
STFC-RAL-CR03 R61: weren't really exposed to what these things were until very much later in life, and that's probably the new hypothesis of, just going through the universe now, probably… I don't know that they're told about these things. So, anyway, that's there. Now, let's think about taking it further.
STFC-RAL-CR03 R61: So, before we go there, there's a few examples to show you how nice… the kind of fun things you can find. So this is a KM experiment, so this is basically an example of
STFC-RAL-CR03 R61: KL, prototy scattering, where you end up with a K-sharp reducible neutron. The interaction happens here. K-shot travels some distance, then it decays to an area of, bions. You can see that very nicely. Neutron goes off, since it's not, you don't see it, because it's neutral, of course.
STFC-RAL-CR03 R61: That's one example of the kind of thing you see all the time. Because you've got a strange rock in the Kon, you generate a whole wealth of strange particles in the… in the interaction. So you see there's these V0s everywhere, it's really nice.
STFC-RAL-CR03 R61: of all of the data to have had, I think this is one of the nicer ones to,
STFC-RAL-CR03 R61: to get hold of, since we have the strange pop in the beams, so we've been making all kinds of interesting articles in the event.
STFC-RAL-CR03 R61: Here's another example of, another interaction. We have a parent interaction going to a lambda.
STFC-RAL-CR03 R61: I know it's a lambda for a reason, which I'll tell you at the moment, and then some clouds, so really excellent.
STFC-RAL-CR03 R61: You can also see all kinds of things, that we know and look into physics like decays. So this is an example of a pion being produced in some family interaction over here, blue over here, very soft. It then basically stops in the chamber. So you can see all kinds of remarkable
STFC-RAL-CR03 R61: It basically gets you back in touch with being a particle physicist in a man. It's kind of
STFC-RAL-CR03 R61: I think it's very nice, and it kind of reinvigorated my interest in a lot of the low-level
STFC-RAL-CR03 R61: you know, things that, we don't worry about too much in a big experiment, or rather it's been taken care of years ago, and we have to worry about it. So, this is all finance.
STFC-RAL-CR03 R61: Right, and so the last bit of the talk, I'll try to outline how you can do some visits with this, maybe. So.
STFC-RAL-CR03 R61: I mentioned that, the first goal was just to preserve it, but maybe we could try to actually get some… some physics out of this again. Given that we have order 10,000, frames, there's around, about 10 or so beam particles for every exposure, so we're talking about
STFC-RAL-CR03 R61: you know, 100,000 or so, rolls of the dice of, okay, I've been going into liquid tragic. So, you're not going to be able to discover anything remarkable, but maybe you could do something interesting, at the very least, use it for some, educational purposes.
STFC-RAL-CR03 R61: So…
STFC-RAL-CR03 R61: Can we… can we basically learn enough about how the analysis was done, and learn enough about technical details of the chamber in our disputes? So, remarkably, the user's mind look for the two-week at Robert Chamber is on CVS at CERN.
STFC-RAL-CR03 R61: Somebody had the foresight of, scanning their whole thing, it's many hundreds of pages, and it's now on TVS, and I was, like, crawled through this, you know, to try to work out how the camera worked, and how to do something with it.
STFC-RAL-CR03 R61: So what I'm gonna try to…
STFC-RAL-CR03 R61: of that is how… just build some very basic feasibility studies to try to look for some standard candles, so to speak, and work out whether or not we can do it. So, the obvious thing to do, given this data set, is, hey, I'm being used to look for change particles. So.
STFC-RAL-CR03 R61: as we just saw, there's copious amounts of case orbs and lambda produced in this dataset. Can we just reproduce the mass peaks and just check that we can reconstruct them at the right masses? That'll be a first step. Let's see if we can do that.
STFC-RAL-CR03 R61: Good, so that's the question, and there's a very big question, just for me, my institute, will hand this work, and, find out what I want this to do.
STFC-RAL-CR03 R61: So this is a quick plan view of the chamber, so we'll now talk a little bit about how these things work for a bit of time. You can't really tell what's going on here, but this is the chamber, this is the flash system, this is the cameras that have been mounted in here. You can kind of… and the whole thing's mostly in 1.7.
STFC-RAL-CR03 R61: So the first thing I've kept alluding to is this three views with which the Chamber is,
STFC-RAL-CR03 R61: Hope you're The importance of this is that
STFC-RAL-CR03 R61: the… it's probably obvious that the reason you want to take the images from 3 different views is to work out in 3D, you have 2D images, and we need to work out 3D positions in the table. So by looking… by taking photos from 3 different views, we can work this up. So here's a quick example of the same event, which…
STFC-RAL-CR03 R61: viewed from three different angles. The cameras are positioned on a circle to put the radius around 30 centimeters. Very fancy lenses, I won't really talk about centimeters, but basically take its
STFC-RAL-CR03 R61: Main thing to take away is that we've got three, 3 images.
STFC-RAL-CR03 R61: What?
STFC-RAL-CR03 R61: So, we've got 3 widgets of every single, booked chamber exposure.
STFC-RAL-CR03 R61: We also now need to work out some way of, for any given feature in the image, on all three of the images, can we work out the three-dimensional position
STFC-RAL-CR03 R61: of that, as a means to work out track trajectories, form a mentor, and whatever. That's… that's all working towards. So the first thing to do is basically work out
STFC-RAL-CR03 R61: So any particular feature that we've identified on each of the three images work back towards a three-dimensional position in the chambers at the reference frame. So, of course, at the time, they were way ahead of me, and they knew that,
STFC-RAL-CR03 R61: We've got to work the side to produce this calibration, so they had these fiducial marks, which were etched into the chamber windows, go to the back window, where the flashlight comes through, and the front window, which you're looking
STFC-RAL-CR03 R61: These had, different mark orientation depending on where they were, so you know in the Z direction, the Z is basically the plane of the axis of the camera, where these things were.
STFC-RAL-CR03 R61: You then also very carefully measure them in real, you know, with a measuring device. So you know very precisely where these things are in the chamber.
STFC-RAL-CR03 R61: Frame. And you can see that these things move… oops, these things move around anyone with a view.
STFC-RAL-CR03 R61: And,
STFC-RAL-CR03 R61: Basically, this gives you the data that you need to calibrate this whole system. So that's what we're going to try and do now, is calibrate our understanding of where the feature is and basic limit is.
STFC-RAL-CR03 R61: to where it is in the frame of the frame. So, we've got some set of traditional marks to do that. We just need to basically do some video arteryx workouts, for a particular position on the film, or rather my digital image of the film, where does it correspond to this geometrial lab space?
STFC-RAL-CR03 R61: I won't read lines, because it's…
STFC-RAL-CR03 R61: But basically, you just need to do some, you write your matrix equation, it's built based on a pinhole camera model.
STFC-RAL-CR03 R61: You assume for now there's no geometric distortions in anything, which we'll talk about then, some of these problems, and then basically you simultaneously fit your
STFC-RAL-CR03 R61: When you identify each of the additional marks in the image, where you know they are in real… from this manual data, you can then build this calibration, work out the whole thing.
STFC-RAL-CR03 R61: There's a few things you've got to worry about, though, is that, one thing is refraction, of course, so…
STFC-RAL-CR03 R61: this is going… this… the light is going through all kinds of different media. It's going through glass, it's going through lithium carriage, which has a refractive index of 1.1, and through lots of air. So actually, if you try to trace the ray of light coming from a bubble, it's got a…
STFC-RAL-CR03 R61: funny path to get to your camera. So you've got to account for this as well. So this is something which I add on top of the linear model from the
STFC-RAL-CR03 R61: I showed you before. But that is the biggest defect and compact, and in much detail, that the rest is fairly small. You might worry about correction distortions in the lens, distortions in the…
STFC-RAL-CR03 R61: film not being flat. There's whole… there's lots of things you… you should rightly be worried about, but it turns out that this is the most important thing. And there's a few other things that I haven't really worried about yet, which might come back to bite me later, but, yeah, for now, we'll see how far we can get with this. So, yeah.
STFC-RAL-CR03 R61: Right, so this is what we do. This is our, fit. So, this is showing you the measured position of the, the process, the measured position of the, pollution mark on the film, and then the dot is where it predicts to be made by, basically, this least squares fit.
STFC-RAL-CR03 R61: And you can see that it kind of works pretty well. This is the three different views, where the different marks are.
STFC-RAL-CR03 R61: see where they're moving around along this circle, and then the residuals, you can see, are around 3 pixels. So we're talking about 50 microns or so, or the kind of width of that track on the film. So we can do a pretty good job of building this model, and at least we can recover the, you know, the typical
STFC-RAL-CR03 R61: Yeah, we can do this fairly well, at least within a width of a track in,
STFC-RAL-CR03 R61: on the bill. So, you can take it…
STFC-RAL-CR03 R61: I'm telling you that, I believe we can rebuild this understanding of going from a, film image to a
STFC-RAL-CR03 R61: Three months are positioned fairly well. We'll see how well that looks in a minute.
STFC-RAL-CR03 R61: Right.
STFC-RAL-CR03 R61: Then…
STFC-RAL-CR03 R61: We now need to do this for every single image that we're interested in. So, what I showed you before was me manually looking across an image, identifying the marks, and then, you know, by eye, looking where the sensor was, and where it should be. We need to work out a way to automatically do this. So, for every single,
STFC-RAL-CR03 R61: image, perhaps, in October, basically, you can use some kind of template matching where you can… you can look for a,
STFC-RAL-CR03 R61: And find it automatically. I won't go through
STFC-RAL-CR03 R61: how that works, because it's not very interesting, but basically, it can do it, and you… this doesn't come out very well, but you can see that with some… basically all of the wealth of, image recognition, pattern recognition software, which is out there on the internet these days, you can do this fairly typical.
STFC-RAL-CR03 R61: It worked very well, and we can… we can reconstruct the… or we can identify the fiducial marks on any given film frame, and then rebuild this fiducial mark, calibration for every single film frame on the go.
STFC-RAL-CR03 R61: And it worked almost as well as it did for the case where we tried all of the market, but sometimes my algorithms don't manage time to hear them because they're in this tracks watching them, or whatever, but…
STFC-RAL-CR03 R61: It works pretty well. So, we can at least do that for any given image that we're interested in.
STFC-RAL-CR03 R61: The next problem is we have to,
STFC-RAL-CR03 R61: look for the tracks. So, you need to find where a track is in an image, and basically work out where the center is.
STFC-RAL-CR03 R61: So, the easiest way to do this is to basically take a… because this is a forward, experiment, most of the traps are very forward, so what we can do is take a slice of the intensity profile, throw an image down, throwing downwards, and basically look at the image intensity as a function of this whiteboard.
STFC-RAL-CR03 R61: They make the tracks correspond to the speeds in there.
STFC-RAL-CR03 R61: in a histogram, you work out, as I showed you earlier on, precisely what the centroid was, and that basically gives you a hit, so to speak, on a truck. So this works pretty, pretty well, and, yeah.
STFC-RAL-CR03 R61: And then here's an example of a pretty busy event, and then when you apply that algorithm, you can get, basically, hits on all of your, tracks, and now you're in a position to do some quantitative analysis on all of these hits. You could really, at this point, treat it like a, you know, a gas detector or a…
STFC-RAL-CR03 R61: many, many planes of them. Now, the hard part, presumably, is you've got to work out packing that mission for me.
STFC-RAL-CR03 R61: All this. Which, as it turns out, is terribly complicated, and it was, it's remarkable that they
STFC-RAL-CR03 R61: did so well in those, excuse me, we'd say that it's, it's, you know, it's a very difficult problem, even now. And particularly when we don't have any beam constraints. These are, these are partial
STFC-RAL-CR03 R61: Yeah.
STFC-RAL-CR03 R61: green passports coming in. You don't know where they're going to interact, so you don't have any constraints.
STFC-RAL-CR03 R61: these interactions could happen anywhere. There's all kinds of backgrounds from delta rays and other cosmics, there's just massive tracks. So, this is clearly a solo problem in how to do the pattern recognition and the track finding, but I don't have the time to do this, so all I did to try to see how far we can go
STFC-RAL-CR03 R61: it's come up with a very, you know, manual, basically look eye-eye at these images, identify where I can see there's a V0 or a K-Shot or lumber, try to identify those, kits through the truck, and, see how far we can go. So, I wrote some quick
STFC-RAL-CR03 R61: Tool to do this,
STFC-RAL-CR03 R61: Now, I should say that there's a whole… with modern machine learning and all of the information, all the track.
STFC-RAL-CR03 R61: algorithms at the NHC and everything that we have in the field today, surely there's a way to do this, but, so don't get the wrong impression this can't be done. It surely can, it's just that I'm not smart.
STFC-RAL-CR03 R61: So, what I do in the meantime is build some… write some code to… to do this manually. So this is a kind of graphical interface that you can basically click around, try to identify where the tracks are.
STFC-RAL-CR03 R61: here is the B0, you know, whether or not it's a conversion or it's a…
STFC-RAL-CR03 R61: H chart on under, we'll see in a moment, and then we can basically overlay all of the hits that we've worked up from the peak finding that I showed a moment ago, then click on a few of them.
STFC-RAL-CR03 R61: and then identify where the track is. Basically, you can click on three of them, that's enough to define circle, and then it basically joins the jobs for you. And then, with all this clicking, you can work out, and you can associate rockets to your tracks.
STFC-RAL-CR03 R61: And it looks fairly good. So… Yeah, that could be good.
STFC-RAL-CR03 R61: So here's a nice example of the same event, where we could see where it's found the hits and then the tracks.
STFC-RAL-CR03 R61: Then, the less hard, but still complicated job you need to do was work out from your hits on your tracks.
STFC-RAL-CR03 R61: then what are the associated particle form vectors that basically do the track phase? So here, we have to put some columns. We have to assume that the chamber, magnetic field is uniform with 1.4, 1.7 volta.
STFC-RAL-CR03 R61: That works fairly well. There's a field map in the, in the, manual which suggests that it's… my uniformity is about 2% or so.
STFC-RAL-CR03 R61: And the field map's in some awkward portran format that I can't really work out. But it's there in French law, so you could do best, but we'll see that using a uniform field works really well.
STFC-RAL-CR03 R61: You have to worry about energy loss at all, so this is like a gas tracking detector or, you know, other stuff CMS, where all your materials in your pixel, layers, or your, you know, piece of hot material, you're constantly going through material, through liquid, and the energy loss, the liquid hydrogen.
STFC-RAL-CR03 R61: You have to account for this in the, you know, track manual.
STFC-RAL-CR03 R61: Otherwise you very quickly realize you don't get the right,
STFC-RAL-CR03 R61: Your postal is very slowly losing.
STFC-RAL-CR03 R61: continue to be using an idea to get it to the channel.
STFC-RAL-CR03 R61: So, you can do this, I won't belabor it, you can work out the… you do the track bits and work out the draw vector of these sort of particles based on the two, parcels that you've, two parts that you've included. This is one of the views, this is the other view, and the tracks.
STFC-RAL-CR03 R61: an SVG tree.
STFC-RAL-CR03 R61: Now, basically, from… you see that all the fixing how it works.
STFC-RAL-CR03 R61: So, with all… I've probably gone over that too much
STFC-RAL-CR03 R61: of a rush, but anyway, you get the idea of what I'm doing. Solve basic stuff in classical physics. But…
STFC-RAL-CR03 R61: it worked. So we can… we've essentially reconstructed this lambda 50 years after it decayed from this, film. So I was surprised it's managed to work, but it does. And you can see now, because we have full information, full access to all the 3D information, we can look not just, through the image, like we were seeing
STFC-RAL-CR03 R61: On the film. We can look down, we can look inside, and we can work on it. So, this works quite nicely.
STFC-RAL-CR03 R61: And now that we have access to momentum, we can work out, is this a lambda, or is it a facial opposite of a gamut? And it turns out this one is very much consistent with being a lambda based on the mass I've passed.
STFC-RAL-CR03 R61: So then, very quickly, we have… I also have a simulation to try to get some more understanding on this. This is… would be a real nightmare to do this without some aid of the simulation, because at least with this, I can, you know, know what's going on.
STFC-RAL-CR03 R61: So there's a GFAR simulation of bubble chamber, and then it makes some artificial film for you to then go and apply all these algorithms to, the same way that you would do, say, an HC experiment.
STFC-RAL-CR03 R61: So, this is… this is fun as well, so we have a simulation frame which allows us to basically know what the right answers and validators are. So.
STFC-RAL-CR03 R61: I've lost over a whole many years of stuff to get to that point, which you might think, that's silly, yeah, Atlas and CMF do that all the time. Sure, they can, but, you know, it was… for somebody like me who didn't have that much exposure, and so this helped a lot, so…
STFC-RAL-CR03 R61: Having a simulation goal is weight, so this is something that should help be allowed to go further based on the…
STFC-RAL-CR03 R61: So that's there.
STFC-RAL-CR03 R61: So, let's see now how well we can do with our goal of trying to strengthen us with massage equipment.
STFC-RAL-CR03 R61: So the first thing we can do, since either of these areas, we can look at this so-called ammentenos called Lundslip. So this… people who've studied these areas will know these things. Well, basically, you can look at two different variables, basically the asymmetry between the mentor along the axis of the KR transverse to it.
STFC-RAL-CR03 R61: when you plot these two variables, you can see different structures which correspond to the different particles. So these are
STFC-RAL-CR03 R61: Anti-lambda, lambda, headshot, and gamma.
STFC-RAL-CR03 R61: So we can very well, in this plane, isolate, whether or not these particles, or what these, things are, irrespective of their mass. So, that's good, and you can see on the data, it's just that
STFC-RAL-CR03 R61: This is from, me drinking through about 500 images, trying to code this tedious clicking, and so on. I managed to find the wheels to get 63 candidates invaded and 51 in simulation.
STFC-RAL-CR03 R61: But then this is enough to… yeah, so you can see that… you can very clearly see the K shots, arc, and the lambda.
STFC-RAL-CR03 R61: We don't see anti-lambda because it's K minus V, but it's strange from the lambda expensed part. So, to reach an anti-lambda in this experiment would be very rare. So, it looks like we can find V0, so that's… that's good. And then we can look at the masses. So, it works. Here's the… the data, here's the simulation of the skew,
STFC-RAL-CR03 R61: tens of candidates.
STFC-RAL-CR03 R61: you can see very well that it's peaking in the right place, both from the simulation to base, and what's more remarkable to me is that they actually read the resolution that you can see, is actually pretty similar. So this, perhaps, in my understanding, corroborates some of these assumptions that I've made about
STFC-RAL-CR03 R61: all of the subleading effects I've glossed over, like the non-uniform… the optical distortions, the fact that the film might be a little bit flimsy and wobbly.
STFC-RAL-CR03 R61: all kinds of things, so at least it seems to roughly work. And with fairly useful resolution, so we could have a resolution around 40 mV on the HR properties, which is not too far from, for example, what I'm supposed to do.
STFC-RAL-CR03 R61: So it seems like it works.
STFC-RAL-CR03 R61: Nonetheless, the contemporary reconstruction would show you much better than this. Some of the papers I wrote suggest that they did do quite a lot better, because they have a much better understanding of what we were doing. But nonetheless, it seemed like
STFC-RAL-CR03 R61: And then here's the lambda, we have a few of statistics. And it works fine, it's in the right place. The statistics are very low, so this is where it would be great if there were some
STFC-RAL-CR03 R61: automated way to identify them. You can see how that goes.
STFC-RAL-CR03 R61: So, basically, here's the conclusion. It seems to work. We've managed to reconstruct B0Ks, so it looks as though the original goal of, digitizing the data in a manner that would be
STFC-RAL-CR03 R61: to reserve the scientific information works. We're now just limited by my understanding of physics and also,
STFC-RAL-CR03 R61: the reconstruction of all of the details from the manual, and then we'll see how far we can go in the future. So, it seems like it's worth pursuing. So, yeah, that's what it was a bit of a rambling…
STFC-RAL-CR03 R61: I hope you found something interesting there. We have a large collection of this film in Danium.
STFC-RAL-CR03 R61: We've digitized many thousands of these images already. You can go and browse them at your leisure on the website, and just look for interesting patterns, interesting decays, try to work out what any given event is telling you.
STFC-RAL-CR03 R61: But also, it looks as though we've done this in a manner with, you know, sufficient density that we can actually get some interesting physics out of this, so at the very least, it could be quite a nice,
STFC-RAL-CR03 R61: ecological resource or training, you know, anything like that. But who knows? We have a lot of data, and this is really terrific, this is interesting data.
STFC-RAL-CR03 R61: we could do something, like reopen the scientific expectation of this for genuine science at some point in the future, though I think we're quite far from that in terms of where we are right now. But nonetheless, that's where we are. So, thank you for listening to me, this ramble.
STFC-RAL-CR03 R61: And I'd be very grateful for any feedback, since it's really just me doing this, and I don't know whether or not this is a stupid idea or not. So, yeah, thank you for listening, and do let me know what you think. Thank you.