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What Black History Month Means to Me - An Interview with Philip Adderley

February 26, 2021 | By KJLC Blog

Philip Adderley

As we come to the end of Black History Month, we wanted to reflect on the diversity of our customers working with vacuum science and highlight the remarkable achievements in their field of research. To do this, we reached out to one of our wonderful customers, Philip Adderley, who is currently a High Vacuum Associate at a National Research Laboratory based in Virginia.

Phil studied Physics at Morehouse College in Atlanta (B.A.) and Atlanta University (M.A.), before embarking on a career in vacuum at a prestigious National Research Laboratory in Illinois, where he had a major role in the development of the kicker magnets for the antiproton accumulator ring. He also developed the conductive coating for the ceramic beam tubes for these magnets. This period allowed him to pick up extensive expertise in vacuum and alignment technologies.

Phil is also a member and former president of the Contraband Historical Society, which is an organization set up to raise awareness of the history, legacy, and contributions of former enslaved people who were considered "Contraband of War".

We caught up with him to discuss his amazing research projects, what Black History Month means to him, and the importance of recognising and encouraging diversity in Science.

How did you get interested in vacuum science?

Philip Adderley

Being born and raised in Nassau, Bahamas, and being naturally curious, I learned a lot of carpentry with my dad who was a home builder, and I wanted to be an architect, or so I thought. I had five older brothers, but one in particular had earned a scholarship for basketball at Morehouse College in Atlanta, Georgia, which is where Martin Luther King, Jr. went. And so, my parents told me that I had to go somewhere where I had an older brother. And of course, they did not have architecture at Morehouse, so instead I studied math and physics and then I chose to do a degree program at Georgia Tech, that I thought would help advance my career path, but unfortunately because of funds I was not able to attend Georgia Tech to work on that second degree. Because of this, I decided to graduate with a degree in just physics from Morehouse because I found that it was one of my best subjects. After graduating, I got an offer, as a summer student, at a National Research Laboratory in IL, which advanced high energy physics research, and there, the things I had learned in physics became crystal clear physically in terms of hands on work - magnets, vacuum, mechanical technology - all was basically in my lap. I ended up being at the Lab in IL for 8 years, and I picked up on vacuum technology because it was necessary, everybody needed it, and as a vacuum technologist I built a lot of components for the accelerator. And so with this skillset, I then learned about the National Research Laboratory in VA where I am at now, and have been for 32 years. My supervisor from the Lab in IL had taken a job at the National Research Laboratory in VA, a magnet engineer, and so I decided to follow him, and the whole world of vacuum unfolded because of my skillset.

Was the National Research Lab in IL then your first exposure to vacuum?

Philip Adderley

Yes, as they had superconducting magnet strings that actually bent the proton beam in a circular racetrack accelerating them to higher energies. Fabricating cryogenic vessels required controlling cleanliness issues for good vacuum when you are putting it all together. Although I did not work with the Cryogenic staff there, I learned the technology and used it to work on the beamline vacuum and components. I fabricated kicker magnets that handled 'kicking' the Protons out of the accelerator when they were not wanted. High current magnetic fields were needed to generate the high rise time fields in order for those kickers to work. But then vacuum was still very important because ceramic beam tubes were needed instead of metal beam tubes so as not induce image currents from the high magnetic fields of the Magnet; Induced image currents are counterproductive. Ceramic an insulator for non-induced currents, required a charge 'coating' for arresting any static charge build up; an overcharge limit would basically cause the ceramic beam tubes to crack. The 'bleed coating' was a very high resistive coating (but conductive enough for charge bleed off) deposited on the inside of the ceramic tubes. Producing these coatings of Indium oxide - films was my first experience with coatings. This led me to advance the capability for producing getter films to achieve XHV.

We meet many customers who have done PhDs in physics but have never learned vacuum technology as part of their course. Do you think university courses should include more about vacuum?

Absolutely! Because it helps to make students concrete learners when they have to understand what is required to create a vacuum, and why it is needed. For example, chemistry has really come out of Atomic physics, because in understanding the structure of atoms which then allows you to see the actual formation of different compounds using the elements and by knowing how valence electrons are shared indicates the building block of interactions of matter. Education advances really depends on where you start and how much you've learned outside of any one particular field to be able to fully grasp your direction and harness your real capabilities. Thus vacuum science is a huge foundation for learning.

In your current role at the lab in VA, you are working with Extreme High Vacuum (XHV) environments, with pressures on the order of 10-13 Torr. How did you learn about XHV and what challenges do you face in attempting to reach those extremes of vacuum?

Philip Adderley

I have learned how to achieve XHV since being here, XHV is similar to outer space vacuum. I worked with Dr. Ganapati Myneni, a low temperature physicist that worked with the superconducting technology division. He inspired me to think outside the box and on a bigger scale, and so I took on the mantra of 'how low can you go?' in terms of vacuum. And I challenged vendors of pumping and vacuum components to really think hard about why is it that you can't lower the vacuum pressure inside the vessel. With this quest of 'how low can you go?' I was able to learn different forms of pumping, both turbo pump backing with a turbo pump and ion pump backing a turbo pump in various scenarios. Because the mechanical action by a mechanical pump on the gas molecules, there is initially turbulence that allows the pressure to be lowered until you reach a molecular flow regime where "random walk" occurs which you can't control thus limiting the ultimate pressure due to the physical way of pumping. So learning new technological ways of pumping was imperative. I was introduced to getter pumps which is basically a very pure metal combination that soaks up different types of gasses (like a sponge on water) depending on the type of metal and the chemical reactions of the gases that the metals will sustain their adsorption. Getter pumping was first reported by Benvenutti (from CERN in Switzerland), I delved more and more into using those pumps, first with pump modules which were appendage pumps added to a beamline or component and then moved into actually developing a sputtering capability (coating) to put it where I wanted it, which I called the holy grail for achieving XHV pressures. In addition, Dr. Myneni was able to demonstrate that the low temperature physics of cryopumping (liquid Helium temperatures; 10-2 Kelvin) that our superconducting cavities use, very easily takes you into XHV ranges. The caveats of all of vacuum capability in terms of 'how low can you go?' are predicated on several things: The first one is purity of materials that you choose for your vessel, its history and then of course cleanliness because the oils in our hands and our hair will outgas, essentially everything in nature outgasses at lower pressures, therefore you have to be very cognizant of what you put in your vessel in order to go to a very low pressures. The holy grail is then being able to find a pump that will pump and hold your biggest residual gas, and we find that using residual gas analysers (RGA's) you can see that any chamber below 1-8 of 10-9 Torr (unbaked) is loaded with water vapor which is your biggest outgassing component and then hydrogen that's very difficult to capture, and especially so since hydrogen is in the interstitials of the metal which seems to be the biggest problem requiring you to process your chamber. Processing is heat treating the metal at up to ~400°C to remove the hydrogen to no longer be a source gas. The outgassing can further be arrested, after heat treating, with the added getter coating on the inside of the vessel, I call this a 'barrier to outgassing'. These vacuum production considerations allowed us to get to 10-12 - 10-13 Torr range and brings up another problem in XHV; that being that low pressure measurements are not as simple as turning on a Gauge as one might think. The best gauging that we have seen [with Dr. M. Stutzman] is the Bayard-Alpert, now turned into the extractor gauge and in comparison with a bent-belt beam gauge (3BBG spectrometer type) that does not have a hot filament. The filament, with its glow, adds heat and is a source of energy in a vacuum system which produces chemical reactions with the residual gases in your chamber, thereby spawning more gas species that must be dealt with via pumping. So, it's like the Heisenberg principle, you can't measure something without touching it and that is profound. We at the National Research Laboratory in VA have experienced lower and lower pressures, by witnessing an extractor gauge read zero (meaning you are below the limit of capability of the Electronics). Dr. Myneni has shown that at liquid helium and liquid nitrogen temperatures, various residual gases freeze on chamber walls via cryo-pumping which can help achieve XHV pressures. One still has to take into account the actual vapor pressure of the liquid, as readily known with water vapour, the liquid vapour for any gas has a huge contribution to the pressure and must be considered based on how cryogens are used. Achieving XHV is very much a linear stepwise process in order to get to lower pressures. [See 'A Road Map to XHV' by P. Adderley, G. R. Myneni]

Working in XHV puts you in a very small and elite class of technologists who are the best of the best in the world. Can you discuss some of the innovative approaches to XHV you practice at the lab in VA?

Philip Adderley

Our innovative approaches are basically material purity, cleanliness, process of chamber materials And then of course Hydrogen pumping, because hydrogen is the biggest residual below 10-10 Torr. range. And also Ion pump technology, which we've done a lot on with Gamma Vacuum (ion pump manufacturer), where John Hansknecht (our electronics Engineer) developed a high voltage adjustment power supply for ion pumps that allowed us to demonstrate over powering, an ion pump limits its effectiveness for lower ultimate pressures. In addition, like getter pumps, the Ion pump plate material is chosen to pump various gas species readily making them more efficient. So when you consider these issues in particular - the chemical trapping of gas species by the plates, the high voltage and energy imparted to the vacuum and the outgassing rate, one can really experience ion pumps that will pump well into 10-12 Torr Range. Because, if it does not, it is now a source of gas in your system. So that's my whole viewpoint of how you can achieve XHV.

You are a co-author on a large stream of publications based on your work at the National Research Laboratory in VA. It seems you get involved in a range of extreme technologies. What is your favourite?

Yes! My favourite job working with Scientists is fabricating and servicing the Electron guns here at the lab where we extract polarized electrons from Gallium Arsenide crystals using specially tuned lasers, so that the timing matches the acceleration frequency of our superconducting linear accelerators. The 'gun' vacuum is very important because electrons are in everything. So, if I have a huge residual gas, the emitted energetic electrons from the crystal (photo-cathode) into the vacuum space impart their energy to the residual gas molecules, creating ions that then hamper your electron beam quality; and since ions are positively charged, they are accelerated backwards to the photo-cathode causing damage to the crystal. With understanding electromagnetic forces, reasoning affords that with less residual gas interactions due to a lower vacuum pressure, the crystal would live longer emitting electrons before it has to be changed. Having demonstrated this quality factor for the photo-cathode, the lab can operate more efficiently in delivering electron beams to the experiments. My contributions lend to the Lab's status as a global leader in producing polarized electron beams for the experiments.

You are currently involved in the Contraband Historical Society. Could you tell us a bit more about what this society is about and what your role and work is within it?

While I was at Morehouse College, Martin Luther King's alma mater, in Atlanta, Georgia, I did not learn about how Africans in America had become free from slavery, and I did not learn about slavery itself, but rather just the Jim Crow era and moving forward to what was called the Reconstruction era. Having moved to Virginia in 1987, I met a lady, Geri Hollins, who was a direct descendant from 'contrabands', and learned that her great grandmother migrated from~ 40 miles away to get to Fort Monroe in hopes of being freed. Less than two months into the civil war the 'contraband decision' took place at Fort Monroe May 24th 1861. And within two months of that decision there were hundreds of enslaved people that moved in and around Fort Monroe leaving surrounding plantations in search of freedom. With that movement of so many enslaved people including women, children, old and able-bodied men, the union army at first did not know what to do with them. Later, they realised the labour potential and put them ('Contrabands') to work. Now, they weren't free but under the protection of the Army; in their minds they were free because they basically 'threw off their shackles' and made a choice. Once I heard that story, not having learned about it in college and being from the Bahamas, it was really intriguing to me, not knowing my own history growing up and wondering where I came from (not knowing my lineage). So it really was an awesome fit for me to get involved in the society. Fort Monroe was there and just working with her (Geri) and learning I was able to meet a lot of people as I lobbied, although not a citizen at the time, and learned that decision makers in the senate of Virginia did not know this history, even others I worked with who grew up in and around Hampton, Virginia did not know 'The Contraband Decision' at Fort Monroe. Gerri Hollins, our Society's founder would go and meet with each new commander of Fort Monroe and there was a large number of them that did not know why Fort Monroe was called the 'Freedom's Fortress'. I was compelled to do what I could to support her efforts. Fast forward to 2005 BRAC (Base Realignment and Closure) commission wanted to consolidate military bases in America, and they recommended the closure and realignment of Fort Monroe in the senate of Virginia. We realised that the history was more important than high income development, as it was on the bay with spectacular views. We lobbied that it should be recognised and converted into a National Park - and fortunately that is what it is today!

Barack Obama signed the executive order for it to become a National Monument in 2011.

Sadly, Geri Hollins passed in 2012, but we were happy that she was able to see Fort Monroe become a national monument.

Currently, I work as much as I can between working full-time and off work times to advance some of the correct terminology to help convey the history raising awareness, because although there are some books {Freedom's First Generation by Robert Engs, Free to Fight by Virginian Pilot, Embattled Freedom by Amy Taylor}, now is the time for a more holistic offering and research, because we believe, and say that had it not been for the Contraband decision that allowed the enslaved to free themselves, it would be quite a different story. What a lot of people don't realize is that the Emancipation Proclamation did not free even those initial contrabands and those that moved into Hampton, Virginia, because the Union Army still needed their labour. At the bottom of the Emancipation Proclamation it reads: 'except these counties…' and Elizabeth County, Virginia, where they were, was one of those exceptions. It is a challenge to convey because the history is intricate and not direct and there are many turns and unknowns in the history due to lost records.

What does Black History Month mean to you?

I think Black History month is really important, and I participate in many of the activities that are going on. I've already had two virtual meetings and there are more events I'm taking part in for the rest of the month. I'm actually working on providing some programming content for virtual celebrations since every year we commemorate May 24th as contraband decision day. This year, due to COVID, we will do some re-enactments on video and perhaps a candle vigil that can be live streamed to include participants. Being a foreigner in America and learning about black history in detail and embracing it, has allowed me to feel more confident about diversity and inclusion. Especially so, since attending Morehouse College, based in the South and well rooted in the civil rights movement. As a Morehouse student, we took on kind of an unwritten mantra that we cannot mess up, we had to be as good or better than anyone else going into a job, not just through grades necessarily but through exhibiting a work ethic and good attitude and that's what I tried to do - and I believe that has taken me all the way to where I am now.

Do you feel things have improved in terms of the representation of people of colour in science or do you think society still has a long way to go in recognising the enormous achievements and scientific work of people of colour and making these more visible?

I feel that there is a lot more that needs to be done, but because we have made a great start with movies, histories and stories that highlight and actually show what has already been done along with achievements by those that had to do so in the hardest possible way, this sets the stage that we can only go further, the more we can become inclusive. Science is one discipline that I have always taken to mean that there is no room for personal pet peeves but rather that it is the diligent work ethic and understanding which matters. So I think we are on a really good path if we continue to let voices be heard in all facets of science and engineering. America is an experiment of immigrants and has demonstrated that different people bring something different to the table. I knew many African American professors who had to really work hard to get their PhDs back in the early 60s and 70s, like Dr. H. McBay in Chemistry who was a graduate student at the University of Chicago when the atomic bomb was synthesized with J. Robert Oppenheimer. I agree that we're literally midgets standing on the shoulders of giants, so it is very important that we include people of colour and people of different backgrounds and make sure that everyone has a voice.

Are there any scientists of colour you particularly admire that more people should know and go and read about?

Guion Bluford comes to mind, he was an American aerospace engineer and NASA astronaut and the first African American to go to space. Also, Victor J. Glover who recently went into space on the Space X crew dragon aircraft last year. There are so many out there that people should know more about!

The vacuum equipment industry continues to grow, driven by cutting edge science at facilities like the National Research Laboratory in VA and pull from commercial applications like semiconductor fabrication, creating new, high skilled, jobs every year. Thinking of your path to vacuum science and your work at the laboratory in VA how do you think more minorities can be attracted to vacuum technology?

I think what can be done is to actually go to the schools and talk about what we do, and expose the students to our work. We have a program here at the National Research Laboratory in VA called BEAMS (Becoming Enthusiastic about Maths and Science) and in my first 10 years here I went to all the grade schools and basically took pieces of vacuum components and devices with me and showed them what I did at the lab to explain all about what we did there. And I really think more of that has to continue so as to draw attitudes towards learning, especially as math and science really requires a lot of hard work and input. Seeing and touching things will inspire students to become more interested; there are many people who do not have the opportunity so it is up to us to bring it to them.

Thank you so much for taking time to meet with us Phil!

Further Reading

You can read more about the great work of the Contraband Historical Society here:

You can read some of the publications Philip has been involved in here:

More about Victor J. Glover here:

More about Guion Bluford here:

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