ALS-United is an opportunity to meet the people collaborating at the Advanced Light Source and the ALS Upgrade Project. Hear firsthand how team science enables the cutting-edge research of today and builds the facility of the future. This month, we spoke with Tianhuan Luo (Research Scientist) and David Nett (Electronics Engineer).
Read the Q&A after the video.
What is your role with the ALS and the upgrade?
Nett: My name is David Nett and I’m the radio frequency (RF) technical lead for the Advanced Light Source (ALS) and I also am the technical advisor for the RF systems for the Advanced Light Source Upgrade Project (ALS-U).
Luo: My name is Tianhuan Luo. I’m a research scientist at the Accelerator Technology and Applied Physics Division (ATAP) in the Berkeley Accelerator Control and Instrumentation group.
What brought you to ALS/ALS-U?
Nett: I work on the accelerator physics, mostly on the RF components, the beam instrumentation, and other electronic components. So, before I came to Berkeley Laboratory, I worked in industry, primarily the defense industry for about 22 years, and then I also worked with linear accelerators for oncology systems for treating cancer.
Luo: Knowing that the Advanced Light Source is a synchrotron that uses accelerators that seems like a pretty good place to come to work because of my work with high-power microwaves and my accelerator background. I visited Berkeley Lab once during my graduate student studies and I had a very good experience. So after I graduated from graduate school, I applied for a postdoc here and I got the offer and I came here and then stayed forever until now.
What is radio frequency?
Nett: Radio frequency energy is better known as radio waves. So it’s an oscillating electromagnetic field. We use it at the Advanced Light Source to accelerate the electron beam and with the Advanced Light Source Upgrade Project we’re adding another ring to the existing storage ring called the accumulator ring (AR). And so ALS-U involves the addition of that ring and we also use radio frequency energy to accelerate the beam in that system as well.
Luo: In a synchrotron light source, first due to the synchrotron radiation, the electrons lose energy. So they need as Dave said the RF to replenish those lost energies to keep them at the same energy level. And then we also need to keep the beam focused. So this radio frequency they also longitudinally keep the beam tight. In this upgrade and also in the ALS, we need some special longitudinal manipulation to control the bunch length, you lengthen them in order to keep them stable. So, all these gymnastics are done by the RF systems.
How do you work together?
Nett: Initially, Tianhuan and I didn’t work together, but with the ALS-U project, the RF cavities that accelerate the beam in the new accumulator ring, I was responsible for helping to procure those cavities, and Tianhuan was responsible for working on designs for those cavities. So, my focus was on the hardware. Hers is more in computations. In helping us figure out what we needed to procure.
Luo: For example, in the recent third harmonic cavities, Dave led the project and coordinated with the LBL with the vendor and with the design. So, I work with Dave to communicate with the vendors to participate in the meeting and discussions and then working together to have the final delivery from them.
What has changed since we came together as One ALS?
Nett: Things have changed since we’ve merged and become one ALS and that’s an ongoing process, but I think initially we’ve been able to leverage expertise from the Advanced Light Source technical team and have them help with some of the integration activities for ALS for new equipment and that’s been really helpful.
Luo: ATAP also provides support to ALS-U like I’m doing the RF and Dan Wang, another scientist is doing the impedance and the diagnostics and also Chad doing the beam dynamics. So, we are all like support for ALS-U.
What are some recent accomplishments you’re most proud of?
Nett: I think that the most successful achievement that my team and I are proud of is the successful installation and integration of the AR RF cavities into the storage ring tunnel. We’re preparing to energize the cavities with RF energy for the first time in about the next six weeks.
Luo: For me, the achievement I’m very proud of recently is the delivery of the third harmonic cavity. I remember receiving the email from them with the data that the frequency is exactly where we want it, which is a milestone for the cavity production. I think it’s a combination of our years of effort of design and the production so we are proud of that.
What is on the horizon for your team?
Nett: Coming up on the horizon we are preparing to energize those AR cavities in the accumulator ring and so we’re on a very tight schedule to have those cavities fully RF conditioned before the summer shutdown which occurs in July.
Luo: So our next project related to the RF is the testing the RF for the feedback systems, including the high power system and also connect the whole power and the control and the cavity, the feedback cavities together to test the whole system.
What do you like to do in your spare time?
Nett: In my free time which right now I don’t have a whole lot of, but when I do have my free time I like to ride my electric dirt bike off in the mountains and I enjoy barbecuing.
Luo: In my free time because my days are mostly simulations so very stationary so I want to keep active and in recent years I started playing badminton and really got into it and next month I’m going to play in a local tournament in the lowest division though.