Name: Yev Lushtak
Yev Lushtak (center) with family
Occupation: Vacuum Scientist (Research Associate III) at the Cornell Laboratory for Accelerator-based ScienceS and Education (CLASSE)
About me: I would like to speak a little about my background. Frankly, before discovering physical chemistry, my background was mainly in truancy and computer games.
I came to the US (SF Bay Area) from Ukraine in 1996. The US science and mathematics high school curriculum is quite a bit behind its post-Soviet counterpart and I very quickly was hopelessly bored. I subsequently dropped out of school several times and, ultimately, decided that finishing high school was not on the table. I wanted to become an airplane mechanic and a writer, but my family insisted a college diploma was non-optional, regardless of what I may do afterwards. Luckily, community college did not require a high school diploma. I spent some time working at a butcher shop (very valuable experience, but that is a tale for another day) and, in 2002, I started at Diablo Valley College (DVC), initially majoring in mathematics.
DVC is a great community college. In fact, the science and math classes offered there were far more rigorous than some of the ones I took at a four-year university afterwards. I initially had a terrible time of it for a number of reasons: I was not very motivated since I had not found an academic subject I was excited about, I had no study skills, and, frankly, I could not force myself to learn anything I found “uninteresting”; the latter defined as whatever I happened to feel was beneath me at the time. Furthermore, calculus without physics to back it up is a boring affair. I got a lot of Cs during my first year, barely passing vector calculus.
I switched to a chemistry major during my second year, after having taken an intro class and finding it somewhat enjoyable. I did better than with mathematics (with the single exception of a C in organic chemistry) but, frankly, I did not feel a particular affinity for chemistry at that point. It was at most interesting enough that I did not feel that I would ultimately abandon it. Eventually, I found a great deal of affinity for physics (and it turned out that I had retained calculus despite the poor grades), but that happened after I had already been accepted as a transfer to a few schools under the chemistry major. Rather than having to incur the fallout that was sure to follow upon telling my family that I would take another year at community college and change majors, I went with chemistry. My first physical chemistry course changed my attitude. Within weeks of starting, I knew I was going to pursue a PhD. Working towards a tangible goal helped me stay motivated and I got As in most classes past that point.
I was offered admission to CUNY in 2008, however, my acceptance went unrecorded due to a clerical error. By the time I checked in after having not heard from the school for some time, I found that the class of 2008 was full; therefore, I would have take a year off and reapply. I was already en-route to NYC, having officially moved out of my Berkeley apartment and there was little I could do beyond taking an adjunct job and waiting. Dr. Mark Kobrak recommended me for teaching organic chemistry recitation and lab; the prospect was a bit scary given my less than stellar performance in that class in college. Luckily, it turned out that the advanced organic and computation chemistry classes I took in the latter college years greatly advanced my understanding of the subject and what had been a daunting affair, rife with flash cards and (ugh) memorizing, was reduced to understanding nucleophile-electrophile interactions and molecular orbital theory. Therefore, the difficulty was mainly getting over my social anxiety and being firm with students. I taught many courses while pursuing my PhD; including intro classes (difficult because students do not tend to have any mathematics background and tend to lose interest), a statistical thermodynamics lecture (which significantly tested my knowledge of my chosen sub-discipline), and even organic chemistry lecture. None were more memorable than that first assignment because it made me face my social anxiety and imposter syndrome head-on, and that was tremendously helpful in my career.
I did my PhD research at Queens College (under Dr. Cherice Evans) and at the Synchrotron Radiation Center in Wisconsin. The project was developing a novel photoemission method and it involved learning a lot about particle accelerators, synchrotron beamilines, spectroscopy, mechanical design, etc. And, while I had trouble finding a postdoctoral position without having intimate knowledge of whatever spectroscopic technique was in fashion that year, the very diverse foundation of skills served me well in the future. The project also awakened a love for particle accelerators that it with me to this day.
I graduated in 2013, and, after a year of teaching at all manner of CUNYs and SUNYs, while vainly looking for postdoc or a professorship, I ultimately convinced myself that perhaps taking a technical sales job was not the end of the world. That was probably the best decision of my career. The job required an advanced science degree, made ample use of particle accelerator knowledge, and forced me to build a network. The latter being something I had neglected to do while in school. I was involved with a number of major projects (I am still on the vacuum committee for next Laser Interferometer Gravitational-wave Observatory (LIGO), for instance). The regular raises, promotions, and bonuses certainly did not hurt, but I knew I did not want to continue the commercial work indefinitely.
Our daughter was born in 2017, making the frequent travel inherent in a technical sales job difficult to bare. In 2018, I leveraged my network and the Computer Aided Design (CAD)/simulation skills I had made part of my job (to a partial chagrin of my supervisors) to get a vacuum scientist position at Cornell University. I go into detail below, but it is as if this job is tailor-made for me.
About My Work:
I am a vacuum scientist at the Cornell Laboratory for ScienceS and Education (CLASSE). This position exists somewhere between accelerator physicist and engineer. Engineers are better-versed in CAD but lack the necessary physics background, while the accelerator physicists are proficient in the ins and outs of beam manipulation better but lack understanding of the other relevant systems, as well as generally not being versed in system design and vacuum components. The vacuum scientist exists at the interface, often taking on tasks from both realms. The position as I have made it requires knowledge of vacuum chamber design, simulation (notably of calculating stresses and gas pressures), gas/surface chemistry, and instrumentation. Understanding the behavior of complex vacuum systems goes far beyond kinetic gas theory and requires thorough knowledge of gas conductance as well as of a breadth of pumping and measuring devices; understanding magnet optics, Radio Frequency (RF) systems, and experimental constraints is also important.
I like this job because it is never boring. There is always something new to learn and whether one decides to focus on a particular aspect is up to the scientist, the job description being somewhat vague. For instance, I spend at least a few hours per month learning more accelerator physics and I learned to do Finite Element Analysis (FEA) on the job; focusing on these items is not required but I enjoy them, and it brings a flavor I like to the experience. Recently, I have become recognized as an authority on FEA and therefore I get to tackle increasingly advanced projects. Sometimes, there is a need for going off the deep end with obscure methods and equipment. This is a great job for someone with many interests.
CLASSE houses a particle accelerator complex, and we do a lot of photocathode and accelerator research. For instance, we recently completed the CBETA project that will pave the way for very efficient energy-recovering linear accelerators. Nowadays, the main attraction is the Cornell High Energy Synchrotron Source (CHESS). It is an X-Ray user facility, meaning that on top of our internal research, scientists from all over the world use our beamlines to various spectroscopy and imaging. Structural biology and material science are big-ticket items at the moment, but we are equipped to adapt to new needs as they arise.
The Cornell Electron/positron Storage Ring (CESR) is a circular positron storage ring (we currently do not use electrons, but we have in the past and may do so again) that is used to create high-intensity X-Rays and send them to beamlines. I mostly work on CESR but I have recently started also working on beamline optics. In any cyclical particle accelerator, highly-relativistic particles are kept in orbit with magnetic fields as they traverse narrow-aperture vacuum chambers. A positron beam of a non-trivial current stored at and energy 6 GeV produces intense light, which in-turn deposits extreme power densities (sometimes as much as 4 kW/m) on vacuum chamber walls, therefore, thermal load mitigation is very important. Chamber aperture transitions must be gentle enough to avoid significant Higher Order Mode Loss (HOML) heating. Furthermore, the maximum acceptable gas pressure in the chambers is around 1 nanoTorr, therefore, vacuum pumping is a huge concern as well. I design vacuum chambers, run stress and deformation FEAs, and perform vacuum simulations. The latter often requires tailored Python code to get around software limitations. CESR is an old facility, with portions of the accelerator complex having been built in the 1960s. It was repurposed many times, initially being used for particle collisions with static targets, then transitioning to positron/electron collisions, then to studying electron cloud effects on positron beam storage, and finally to a dedicated X-ray source. Charged particles traversing magnetic fields always produce synchrotron radiation, therefore, as far back as the 1980s, some of this radiation was used for beamline experiments. At first, bending magnet radiation was used parasitically. This was followed by installation of a few insertion devices (undulators and wigglers); the latter produce better-quality light (more monochromatic, better-focused, etc.). However, given that X-ray production was not the main event, so to speak, geometric and magnetic field limitations made achieving high-brightness beams impossible. In 2018, a major upgrade recast CESR as pretty much entirely an X-ray facility. Since parts of the accelerator are quite old, with people who had designed various components retired or dead, maintenance presents interesting (and frequent) challenges. The vacuum scientists tend to be the first link in the maintenance chain, either fixing things right away or deciding which specialist is called in. Therefore, knowledge of all accelerator systems is important. Again, as someone who cannot commit to a discipline, I enjoy this quite a bit.
Advice About Entering the Field: There are a few lessons to be learned from this story. First, the path to success (as vague at that is as a concept) only makes sense in hindsight; it is rife with detours and seeming dead ends. Second, it is always possible to learn something useful even if one’s career path has not been sorted; no one will take your thirst for knowledge away and it is smart to indulge it. Third, there is always room for a comeback. And, fourth, and most importantly, networking is everything. Technical skills matter little if there is nowhere to apply them. These days finding a job requires getting through layers of recruiters and HR, and, unless you are a known specialist in whatever technique they are hiring for, getting through is nigh impossible without friends on the inside.
As for the job, sadly, vacuum scientists are becoming increasingly rare. Most likely for budgetary reasons, facilities tend to pile the duties on mechanical engineers. I will reserve judgement of this practice since many of my friends are mechanical engineers; suffice it to say, I feel like there is room for both. Also, unfortunately, post-doctoral assignments have gradually migrated from the “do something new” realm to the “cheap labor” realm. The latter tends to require experience with similar experiments to what is being performed on top of offering little new breadth to one’s knowledge. I find that exceedingly unfun and therefore I recommend being a generalist (mid-level knowledge of a lot of things makes it easy to close the gaps as needed) and using one’s network heavily; physical chemistry offers a better foundation than other chemistry subdisciplines or physics, but knowledge is more important than the type of PhD. Taking a commercial job for building a network while continuing to hone technical skills worked for me. That might not work for everyone, but I think it should be on every young scientist’s radar.
I should also say also that it is a good idea to be familiar with the X-ray facility (often called light sources or just synchrotrons) world since these house thousands of interesting science and engineering jobs. There maybe not many vacuum scientist positions per se but there are dozens of chemists/biologists/physicists working as beamline scientists in each facility. The latter positions tend to be a bit more focused, but they offer many new challenges and ways to learn something new.