Day in the Life of a Nuclear Physicist | Kelly Chipps

[00:00:03] Nuclear physics lets us operate in this kind of way that on any given day I might be in the laboratory doing an experiment with my colleagues and trying to understand the data as it comes in. I might be there interfacing with the accelerator operations staff trying to make sure that we have the best possible beam.

[00:00:22] But I might also be in my office writing a paper about the results from the previous experiment that we wrote, or I might be in the lab space across from my office putting together a new detector. So there's all sorts of different things that I might be doing on any given day, and they can range from working on the computer to being underneath a vacuum chamber with a wrench and tightening bolts. So I really appreciate that.

[00:00:58] Welcome to My Nuclear Life. I'm Shelly Lesher. And today, a little bit different is that we are heading right into a conversation with nuclear physicist Kelly Chipps. Hello. It's good to be back. Yes. So did you buy anything off our Christmas list? Oh my goodness, I did. I bought one of those very fancy watches that has the dosimeter inside of it. We've actually gotten a chance to play around with it. So fun and excitement here on the farm, as they say. Does it work?

[00:01:27] It does work. We have worn it next to some radioactive sources to make sure that we can measure the dose rate from them, and we can. Excellent. I bought one of those mushroom cloud lamps for my bedside table. Yes, it was fun. There are a few other things on my list, but we'll see. You've got to finish the whole scheme, the whole decorating scheme. So what do you recommend next then?

[00:01:50] I was a big fan of those very kind of atomic-looking light fixtures, the ones that hang from the ceiling and look like electrons moving around a nucleus. I'll let you know when that's finished. I wanted to have you back on because summer's coming, and to me, as an academic, that means, as an experimental physicist, I actually get to go do physics now because classes are out.

[00:02:19] You're not in academia, but I'm wondering if that's the same for you. Once summer hits, is it kind of more experimental season or not? Summer is definitely a travel season. A lot of conferences, as you know, are held in the summer as well because they're trying to work around the academic schedule. So summer is when a lot of people get together to talk about the research that they've been doing. What's on tap for you this summer?

[00:02:44] So we are actually in the middle of an experimental campaign, which is a set of six experiments, almost back-to-back, basically a week or so at a time. And then in between every few, we have to go into the system and reconfigure some of the detectors and then start over with a new configuration and a new set of experiments.

[00:03:08] But this has basically been taking up our time since about mid-February, and it will go until the end of almost the end of May. So when you say this campaign, do you have an experimental hall? Like, do you have the ability to do experiments where you are? So let's remind folks where you're located. So I am at Oak Ridge National Laboratory, which is just outside of Knoxville, Tennessee.

[00:03:32] We do not have a nuclear physics facility on site, although we did used to historically. We had the Holyfield Radioactive Iron Beam Facility, which was named for a very prominent political supporter of the laboratory at that time. Since we do not have a facility on site any longer, we travel to do our experiments.

[00:03:54] So we're doing these experiments to kind of study the reactions that power stars and stellar explosions, things like supernovae, neutron star mergers even. We want to understand how those elements are being generated in those cataclysmic events. And in order to do that, we have to study those nuclei and study those nuclear reactions. So to do that, we go to, generally speaking, one of two major facilities in the U.S.

[00:04:24] Both of these are Department of Energy-run facilities. The first is the newest of the DOE nuclear physics facilities, which is the facility for rare isotope beams. We call that EFRIB for short. That's on the campus of Michigan State University. So in February, it was quite cold for you coming from Tennessee to go to Michigan. It is, yeah.

[00:04:47] It's always a little bit of a shock to leave 60-degree weather and end up in a snowstorm later that day. Yeah. Yeah. And what is the other one? Is it a warmer facility? It is not quite. It's the Argonne National Laboratory's Atlas facility, which is just outside of Chicago. Not to be confused with Fermilab, which is also just outside of Chicago.

[00:05:11] But it is also an accelerator facility that is operated by DOE for low-energy nuclear physics research, like the type of research that I do. This facility runs something like 6,000 hours a year. They basically just keep going 24-7, 365 to support users like me and my collaborators. So you said you're at EFRIB, the MSU-1, since February.

[00:05:37] So you'll run a week and then you'll take a week off and then you'll go back for a week? That's basically how things are done, yeah. So now that we do not have our own in-house facility, a lot of what we do is development of new tools and techniques that can be used at these other facilities.

[00:05:56] So, for example, we have a device called the EFRIB Decay Station Initiator, which is a set of really complicated different detectors that are all kind of combined into one. And we put that on a beamline at EFRIB and we can study exotic nuclei using that device. Another device is what we call GADIS, which is the Gratina Aruba Dual Detectors for Experimental Structure Studies.

[00:06:25] I know that's a mouthful. It has an acronym inside of the acronym. You really had to, like, search for that acronym, didn't you? That one, yeah. Sometimes you choose the name and then you fit the acronym around it. That is a secret of science. And sometimes you find the acronym and you fit the name around it. Although I do have a colleague who has advocated for us simply naming things. It doesn't have to be an acronym. It's, you know, the name Shelly is not an acronym. It's just your name.

[00:06:53] So perhaps we should just name our devices. Something like Bob. I think I saw that someone was giving a talk and their detector's name was, like, Fred. And people are like, what? Why Fred? And they're like, because that's the name of the detector. That's his name. Yeah. So you know about Fireball, right? I do. I know about Fireball. It's very exciting. Do you know how the name came about? I don't know that I know this story. No. It's a great name. So I would love to hear it. Ah, thank you. So it was Iceball.

[00:07:22] Iceball was the name of the detector. So it stands for Internal Conversion Electron Ball. Okay. Says exactly what it is. But we needed a new name to so people could appreciate that we upgraded it. But it's a perfect name. So all we did is it still stands for Internal Conversion Electron Ball. But it's now Fireball. And we use different capitalizations. And the F is small. It's a silent F. Yep.

[00:07:52] A silent F. And we just capitalize different things. And the students keep making things up for what the F stands for. But it doesn't stand for anything. It's just its name. See? You have Goddess, you mentioned. Goddess is actually quite a few detectors. We have on the order of 800 channels of electronics. What that means, we have a series of detectors. There's several dozen of them, actually.

[00:08:21] And we mount these in kind of a barrel configuration. So it looks like maybe a can or a barrel that's been closed around the target location. We do that because it makes the math easier, right? If we could make it a sphere, that would make it even better because we're working in polar coordinates. So we have this barrel and then that goes inside of a vacuum chamber. These semiconductor detectors like to operate at vacuum so that the electric field inside them,

[00:08:51] they're basically just diodes. You don't want that electric field to break down, so you want to remove the air around them. And then that also helps with detecting the particles that are going to come out of this nuclear reaction because these particles are charged. And so if they're traveling through air, they're going to lose that charge as they bump into all of those air molecules. And eventually they're going to stop and you might not detect them. So you want to get rid of all that air. So that's inside of our vacuum chamber.

[00:09:19] And then outside of the vacuum chamber, we have more detectors. These are the Gretina detectors. Gretina is the gamma ray tracking array, which is soon to become Greta, which is the full array which covers the entirety of a sphere. Right now we've got about a third of a sphere, which is why it's called Gretina. It's little Greta. It's not full Greta. This is something that you'll see in physics, too, where if you don't have the full one, then you'll call it the little full one.

[00:09:48] These detectors are really state-of-the-art. This is something that the entire community in the U.S. is really behind having access to these detectors because they really push the boundaries of what we're able to do when measuring gamma rays. So when you put these together, you get gamma rays, you get the charged particles, and you can really in-depth understanding of what's going on in these nuclear reactions. We've been working on this.

[00:10:15] Well, we, not me, we as a community have been working on Gretina for quite some time. I remember the group working on it when I was in Berkeley over a decade ago. Yeah, this is something that's been really a long time coming. It took a lot of funding, a lot of support from the funding agencies like Department of Energy to make this happen. This was something the Biden-era IRA actually boosted the funding for Greta to make sure

[00:10:45] that it could be completed on time, which was definitely a boon for us because that would have stretched it out longer and we would have been waiting even longer. But thankfully, I mean, last week, it was just last week, they had a dedication, a little celebration workshop. People talked about the science that they've already managed to do with Gretina and we talked about how much we're looking forward to Greta. And does it matter where it's located? So you mentioned that it's at Ephraib now. Does the beam matter?

[00:11:13] It does matter because it's a community device. It's meant to kind of travel where it's needed. Gretina thus far has bounced back and forth between Ephraib and the Atlas facility at Argonne. One of the really powerful things about Gretina and in the future Greta is that it can track a gamma ray as that gamma ray bounces around inside the array.

[00:11:40] And that's more likely to happen the higher energy you're looking at. So if you're at a facility like Ephraib where the beams are very high energy, this is really going to buy back a lot of information that you would have otherwise lost because that gamma ray would have bounced around, but none of those interactions would have been recorded. So if you are looking at something where you have these high energy gamma rays and they're

[00:12:05] really bouncing around everywhere, that's where you're going to gain a lot with Gretina and with Greta. So you say it moves, but you also mentioned that there are hundreds of channels of electronics. That doesn't seem easy. It is definitely not. There's a lot of people who are involved in making this happen. You have everything from, you know, someone who's a mechanical engineer who operates the crane

[00:12:34] to move these detectors in and out of their frame because the detectors themselves weigh quite a bit. They are heavy and they are also fragile, so you don't want to drop one. Then you have electronics engineers and computer folks, people who do coding, who are helping to make sure the data acquisition system, which we call DAC for short, is being set up properly in every location.

[00:12:59] You have everything down to, you know, carpenters who are building crates to pack this stuff into so that it can be put on a truck and moved safely between facilities. And on top of that, you've got the scientific staff at the different facilities and scientific staff at the laboratory where Greta was originally built at Berkeley who are supporting this whole

[00:13:24] endeavor as well and making sure that, you know, when the detectors are installed in a new location, that the data looks like it's supposed to and that everything appears to be running properly. So I want to talk about what happens when you go to an experiment. So these are really kind of exhausting endeavors. They definitely can be. But one of the things that I appreciate about nuclear physics as a field is the fact that

[00:13:53] things aren't the same day to day. You know, on any given day, I might be doing any number of different types of tasks. And this is also true when you're running an experiment. So you might show up in the morning and maybe it's time for the experiment to start. And so the facility is tuning their beam to you. This might be a stable beam. It might be a beam of radioactive particles. But they have a whole accelerator.

[00:14:22] They have to get that particle from the start of the accelerator to the end and have it come out into your target chamber at the right energy and in the right position. And that takes a lot of time and diagnostics. They have to be able to see where the beam is at every stage. A lot of times that requires feedback from us. Maybe we have different diagnostics than they have that we can give them.

[00:14:46] You might be interfacing with the staff in real time, the accelerator staff, to make sure that things look okay. But you might just be waiting for them to do their part and to hand things over to you. So you just sit there and you wait for hours. Sometimes there is a lot of waiting, yeah. Now, this changes if you're at a small facility. So if you're at a university facility. That's true.

[00:15:13] So if, for example, you were at one of the university facilities as part of ARUNA, which is a coalition of small university nuclear facilities, you may actually be one of the people who's tuning that accelerator. I know this is true at the University of Notre Dame, for example. Yes. So if you don't get beam, it's your own damn fault. It's your own fault. It's always fun. You don't necessarily have to be an expert in ion optics.

[00:15:43] Ion optics do behave a lot like normal optics, like people are used to. There are basically electromagnetic equivalents to different types of lenses. So you can focus, you can defocus, you can steer, you can do all sorts of interesting things with the shape of that beam. Think of it like a beam of light and you're just trying to get it from one end of the accelerator to the other. Explain how big these beams are.

[00:16:10] Like a pencil dot, a crayon dot, a pen dot, like how big? Yeah, it depends on what facility you're running your experiments at and what type of accelerator that they have. So if you have a tandem accelerator or if you have a linear accelerator, a LINAC is how that's normally referred to, you can have a very nice beam spot. What that means is that your beams coming in, it's very parallel. It looks basically like a, you know, a pencil or a beam of light.

[00:16:40] And that beam spot might only be a few millimeters across. And that's great for us because that's basically the same kind of segmentation that we have in our detectors. So we're not limited by the resolution of the beam spot. The beam spots are basically the same size as the resolution of the detectors. So you're, you've matched, you're at your optimum.

[00:17:05] If, for example, you are running a beam that has been created through fragmentation or spallation or maybe an in-flight production mechanism where you have a reaction and you send all of those particles forward, then the actual mechanics of the reaction are going to spread that beam out. You can do a little bit of steering and try to get that beam spot back down again.

[00:17:31] But generally speaking, because there's now an energy spread that's been induced by the production reaction, you can't get around that. That means that your beam spot is probably going to be a bit bigger. It might be on the order of a centimeter across. Really? Yeah. I can't believe I didn't know that. Yeah. So that's one of the tricks running at a facility like Ephraib. And this is one of the places where we were talking about Greta and Greta being able to track those gamma rays as they bounce around.

[00:18:00] Being able to track the gamma rays as they bounce around allows you to back calculate where that gamma ray originated. So you can actually undo the effects of having a really big beam spot because you know you can calculate where on your target or where in the beam spot that gamma ray started. Wow. So you get your beam and five o'clock comes and you get to go home? If only.

[00:18:29] So one of the exciting things actually about doing nuclear physics is that these facilities do run 24-7. It is a lot of effort and a lot of, in the end it's money, but it's electricity and the cryogenics that it takes to cool some of these magnets down, for example. And there's a cost to turning them on and off. So it's much more efficient to just keep going.

[00:18:57] And instead of turning it off at the end of the day and starting again fresh the next day, you just keep running. So when we run experiments, we're running those experiments 24-7. And so you have to have people there 24-7. And that does mean that we have to have people here 24-7. So you definitely get to find out who amongst your collaborators is the early morning person and who is the night owl. People tend to gravitate toward the time of day that already works best for them.

[00:19:25] So sometimes there are. When I was a student, I could easily stay up until 2-3 in the morning. And so that's what I would do. But it's not so easy anymore. So, you know, now I'm the person who comes in first thing in the morning. It's usually the graduate students that are taking the midnight to 8 a.m. shift. It is. I think, and we've all done it. I know that this is actually one of those silly benefits to having international collaborators

[00:19:52] that someone flies in from Japan or somewhere in Europe to participate in your experiment. I've known people who have come, say, from Europe over to the United States to run an experiment, and they just keep on their own time. They don't try to shift over to Eastern time zone or Central time zone. They just stay on European time, and they take those night shifts because that's basically the daytime for them.

[00:20:21] And then they sleep during the day because that's basically nighttime for them. It works out really well. There's enough of an acknowledgement in the community that this is true, that there are actually guest houses at some of these different facilities. I know that the Triumph facility in Vancouver in Canada explicitly has guest rooms with no windows in them for people who want to do this, who want to come over and stay on their own

[00:20:48] time zone and sleep during the day and be awake at night. And being able to have a room with no windows means that they don't have to worry about the sunlight coming in and messing up their circadian rhythm. Wow, I didn't know that one. Yeah. That makes sense. So on this set of experiments, are you doing a week on, week off? So are you flying back and forth every week? So we are doing kind of two to three weeks on and a week off.

[00:21:15] So we go up for about three weeks at a time and run maybe two experiments back to back. And then we spend a week shifting the detectors around. Like I said, it might be that the reaction that you want to look at is more forward focused or backward focused in the laboratory frame. So you have to move the detectors more forward or more backward, put them basically where you're going to be getting the most information, the most bang for your buck.

[00:21:44] That usually takes about a week or two weeks. And so after that's done, we come back for a week. We try to catch up on all of the office work that we've been putting off for those few weeks. And then we turn around and head back up to the laboratory to get another set of experiments done. So this is a lot of time that you have on a national facility. How does that work? Like how do you get time on a national facility? Well, an international facility, actually. So one, how do you get time?

[00:22:14] And two, how did you get so much time? This is one of the really great things about our community is that we run these facilities in a competitive way. And that competition is essentially self-determined. So what that means is that we're taking experts from the community. So it's a jury of our peers who come together every, say, six months to a year for each of these facilities. These groups are called the Program Advisory Committee or PAC.

[00:22:44] There are different names sometimes at the different facilities, but the idea is the same. You have these groups of peers come together and you will submit proposals to them. This call for proposals will be open to the entire community. You don't have to have run at that facility before. You don't have to have a national lab job. You don't have to have a full professorship somewhere. It's open. And what you would do is you'd say, I would like to run this experiment.

[00:23:13] This is why it's important. Here's how it would work. Here are the things that I would need to make it happen. Here are the things that I would measure. And then here is the anticipated output. So, you know, if the experiment was successful, this is what information we would get out of it. And you submit those proposals to these call for proposals. And then the PAC members get together. It's usually in person in a room for about two days. And they read through all of those proposals.

[00:23:44] And they debate the merits of the different things. They might reach out to the people who wrote those proposals with questions and say, you know, you mentioned that you want to measure this and this. But do you think that this particular thing could get in your way? And they'll try to collect all that information. And then they will rank those proposals based on the quality of the science case and feasibility of the experiment.

[00:24:11] Give that recommendation, kind of that ranked list, to the facility director. The facility director will then say, you know, yes, I agree with your list. These experiments have been approved. And then the remainder generally are given some constructive feedback and said, go ahead and try again next year. It's a very competitive process. Usually only about a third of the proposals that are submitted go through.

[00:24:38] It is possible to submit, say, to the next PAC. It might be nine months or a year away. And maybe you'll be more successful then. Maybe you learned something. You took their constructive criticism and you implemented it. And you discovered that there was something that you had missed. And so you can actually improve your own proposal by taking that feedback. So do you have a lot of members of the community on this set of experiments? Yes.

[00:25:04] These experiments that we're running right now, they were approved at, I think, three or maybe four separate PAC meetings. So sometimes when your proposal is successful, it doesn't necessarily mean that it's going to run right away. Right. So one of the things that we, for example, needed, right? Like we say, here's the science case. Here's the thing that we need to be successful measuring this. And one of those things was Gratina.

[00:25:32] And so that means that we can't run this experiment until Gratina is available to us. That's why we're actually running six experiments, basically, essentially back to back right now, is because Gratina is available right now. So we kind of run while we have access to Gratina in the place where we need it, on the beam line where we need it, with the equipment that we need it with. And then someone else will do the same as soon as we're finished.

[00:26:01] And then Gratina will get packed up and it will move again, become Greta, and do this bouncing back and forth to the different facilities like it's been doing. Wow. Okay. I get it. So there's been kind of this backlog of proposals just waiting for the stars to align, essentially. In some sense, yeah. And I mean, sometimes these things are kind of, for lack of a better term, standard. You might have a proposal that says, like, I want to use this very standard piece of equipment that's always available.

[00:26:32] And sure, that might be able to run soon after the proposal is accepted. It's getting those things actually on the schedule and having them run at the facility is then the job of the facility director and the user liaison who work with the people. They say, hey, what is your availability? If we schedule it in October, can you come or do you have teaching duties that we need to work around?

[00:26:55] They're trying to balance the needs of the whole community and make sure that they get all of these things kind of into place so that everyone can get the most out of their experiment. So what happens if you go and you have five days of beam time and one day in something breaks and you don't have anything? Like the beam's gone for the rest of your time. Do you get to stay for another five days or the next person gets to go?

[00:27:25] It depends on the facility to a large extent and how many hours they're allowed to run. If something does break and it's on the facility side, so the beam disappears, say there's a problem with the ion source or there's a problem with some other component of the accelerator. They will work and they will work 24-7 to try and fix that problem right away so that they can get you back running again.

[00:27:52] If for some reason they're not able to do that, if they know that it's going to be a few days, maybe there's a part and they've already gone through both of their spares and so they have to order a new spare. And this is something that they do, right? They have critical spares for everything so that someone can come in and in an hour have that thing swapped out and back running again. We've both been here, haven't we?

[00:28:15] There's a lot of waiting that's involved sometimes because you know what it's like when you're trying to, you know, say, fix the disposal under your sink and you find that once you fix one problem, another problem was caused by that first problem. And so a lot of times it's hard to predict, but they try it, they keep people available and they keep the parts available so that they can do these kinds of repairs as quickly as possible.

[00:28:43] If they can't, they will ask to reschedule you. So sometimes if you lose, say you lose one day out of the five days, you can ask the facility, say, we lost one day out of five days. Without that fifth day, we won't get the answer that we need out of this experiment. Can we please have one extra day? And the facility, depending on their schedule, generally say yes.

[00:29:10] They'll say, look, we understand that was a problem on our side, so we will give you an extra day to try and make that up. Sometimes that's not possible because maybe the schedule is such that someone needs access to that equipment or that beam line or something. And then they'll say, well, we understand that your experiment did not conclude successfully.

[00:29:34] We want to reschedule you to come back maybe, you know, in three months time or six months time or something like that. They'll try to get you back on the calendar to make sure that you're successful. Now, this does, of course, ignore the fact that if you were down for a reason of your own doing, then they don't have to reschedule you. If the experiment fails because you weren't prepared, that's on you. That's not on them. So how often does that happen?

[00:30:01] We have lost some time to self-induced issues, let's say. I do remember several years ago running an experiment where eight hours of beam time were lost because we were hitting the target frame instead of the target. Unfortunately, nobody noticed it was a midnight shift and they were struggling to stay awake. So they just saw that there was data. They didn't think to check that the data was the right data.

[00:30:29] So you got aluminum instead of whatever you were looking for. Nice, thick aluminum target. Yep. So you do have to always be watching out for stuff like that. So when you run in an experiment, you know, it really is 24-7 and people are always kind of around and trying to check and make sure that things are going well, both on the experiment side and on the accelerator side. So that goes to show that it is high stakes, though, right?

[00:30:52] Like if you only have four days, you ask for four days, you get four days, then every eight hours counts or every four hours. So you have to be paying attention to what's coming in and if you're seeing what you're supposed to be seeing and that you're actually clicking save so that you're not losing data. It is very important when we're running experiments like this that there are people actually physically there.

[00:31:15] I mean, this is something that I know a lot of people in scientific fields struggled with during COVID was not having in-person access. And that's something that's very important in our field. So, yes, you can log in on a VNC and you can watch the data acquisition and make sure that the start button gets pressed. But sometimes you really have to physically be there and go into the vault and check and make sure that the detectors are behaving the way that they're supposed to.

[00:31:44] Because if not, you're in danger of not succeeding in your experiment. So I want to change gears a little bit in what is involved. I'm going back to these like hundreds of channels of electronics. I can imagine that if something goes wrong in those electronics, it's hard to pinpoint where it is.

[00:32:06] It can be sometimes, but this is one of the reasons why it's useful to become very knowledgeable about your setup. Sometimes maybe it's your setup, like I was saying, we built these detectors, we built these devices, so we're very familiar with them. But sometimes it's a detector or a device that's supported by the user facility itself. And so there's someone there whose job it is to be very familiar with that piece of equipment.

[00:32:34] The SACAR, which is a separator for capture reactions, is a perfect example. We actually have someone at the facility for rare isotope beams whose job it is to make sure that SACAR is operating the way that it's supposed to so that the users who come in to do experiments get the most out of those experiments. So what's the strangest thing you've had to figure out? Like troubleshoot. What is the thing that you troubleshooted that took the long... I'm going to give you two scenarios.

[00:33:03] One, what's the strangest thing you've had to troubleshoot? First question. And two, what is the thing that you had to troubleshoot that took the longest and you went, oh my God, why didn't I see that four hours ago? So interestingly enough, the answer is the same for both. It's the same circumstance. We were preparing for an experiment at EFRETH. We had all of our detectors in the chamber. Everything was pumped down and it vacuumed.

[00:33:30] And we thought that we were ready to take beam, except that we were seeing this really weird electronic noise in our detectors. So when I say noise, and this is something that's maybe, if you don't think like a physicist, you might picture something different. So when I say noise, what I mean is that it's like static. It's like when you get static on your television, it's kind of there in the background. We couldn't tell where it was coming from.

[00:33:54] It was so big, it was so strong that it was swamping where we knew the signal that we wanted was going to be. Okay. So we had to find this noise and get rid of it. But we were searching for hours and hours. I mean, just plugging and unplugging cables. We were checking to make sure everything is grounded because sometimes things aren't grounded properly. You get these strange signals.

[00:34:16] We were wrapping things in aluminum foil because sometimes that helps if you have a cable and maybe it's kind of acting like an antenna and it picks up noise. I mean, we've seen noise being induced by fluorescent lights in the room. So there's all sorts of crazy places where we think this might be coming from and we cannot find it and we cannot find it. And then we're thinking like, okay, this is getting ridiculous.

[00:34:42] We've turned off a lot of stuff and it still hasn't helped. And it's getting to the end of the day and it's starting to get cool in the laboratory. So we're like, okay, well, let's turn off these box fans because it's getting kind of cold in here. And we turned off the box fans and the noise went away. And these were just these, you know, your standard $20 jobs from Home Depot. It's just box fans that have been plugged in to keep the electronics cool.

[00:35:12] We've done this before. And we know that when you have a fan, you have to plug it into what's called the dirty power. Your data acquisition system is plugged into clean power. Clean power, it goes through a filter. So it's still kind of your normal three phase, like you're got out of a wall socket, except that it's got a filter on it so that it doesn't have any sort of weird spikes in it. The dirty power is just the stuff coming out of the wall, right? Like there's no filter.

[00:35:39] Unfortunately, someone this time around had plugged those box fans into the clean power. Oh, no. Was turning the clean power into dirty power. These fans are just cheap little motors and they are, when they're running, they're putting noise back into the system. And that noise goes through the electronics and into the detectors and we could see it. And no one thought to check that. And no one thought to check because we thought, well, we always run these fans. It's fine.

[00:36:08] They are only fine if they are not plugged into the same socket. Oh, I bet you've never done that again. Nope. Did you go home then? I would have just gone home. That was a, yeah, we found it. We are leaving these fans unplugged. We're ready for them to start tuning to us. We're going to go get dinner. Yeah, that's fair. So we're coming at the end of our time. What is, I want to ask you before we go, what is your favorite part about being an experimental nuclear physicist?

[00:36:37] Honestly, I think it's the people. I like going to an experiment. You get all of your collaborators together or as many of them as can be there at that time. They're coming from across the U.S., maybe across the world. You get everybody together in a room. You're looking at data as it's coming in. There's excitement. Everybody is there together looking at things, trying to figure out like, oh, what is this, you know, line? Where's this gamma ray coming from? What does this thing mean in the data?

[00:37:05] And it's very collegial and it's very exciting and it's just a really good feeling. And I would really hate to give that up. I think that would be the very last thing that I want to give up if I had to, say, change fields or go into some sort of different job. That would be the thing that I miss the most.