Thanks to the hard work and dedication of multidisciplinary teams from groups across the Advanced Light Source (ALS), a spate of important milestones occurred over the past month, for projects involving the new QERLIN beamline, the MERLIN beamline upgrade, and a new chamber for computer-chip metrology in Sector 12. These events mark welcome forward progress in projects that will play key roles in the future of the ALS.
After midnight on June 27, the QERLIN and MERLIN beamlines (no relation) both opened their beam shutters, exposing new and upgraded optical systems for the first time to synchrotron radiation from the ALS. Both source points had been in operation previously, but substantial replacements and upgrades of the beamlines’ optical systems required a thorough reevaluation of their safety performance. As a consequence, the achievement of this milestone is a notable accomplishment, signifying that the next important step—commissioning of the optics—can commence.
In addition, a new-to-the-ALS chamber for computer-chip metrology, which had originally been installed at the Advanced Photon Source (APS), received ALS synchrotron light for the first time on July 5. This chamber, now at Beamline 12.0.2, will use resonant soft x-ray scattering (RSoXS) to measure feature dimensions on microelectronic chips. It is part of a project with the Center for High Precision Patterning Science (CHiPPS), a DOE Energy Frontier Research Center (EFRC) that was recently granted approved-program status at the ALS. This project is being led by Cheng Wang, a staff scientist in the ALS Scattering Program.
“To get to this point in each of these cases took large teams of scientists, engineers, technicians, and operators, and I want to thank you all for the hard push to achieve these milestones before the summer shutdown,” said ALS director Dimitri Argyriou. “As we work to build ALS 2.0, we will need to work as one ALS, as one team to complete the complex work in front of us. These milestones demonstrate to all that we will be successful in that endeavor.”
Andreas Scholl, ALS deputy for science, acknowledged that the development of the new hardware and the evaluation of the safety envelope took more time than originally expected, influenced by factors such as the disruptions of COVID, the parallel execution of very substantial project work on the ALS floor, and the increased safety requirements of the new accelerator replacing a 30 year-old system—the latter effort being led by Stefania Trovati, the ALS lead radiation physicist. “I am thrilled that we have now reached these milestones,” said Scholl. “It required a concerted and well-coordinated effort by a multidisciplinary team of scientists and technologists in the ALS and Engineering Division. Congratulations!”
The phased upgrade of Beamline 4.0.3, known as “MERLIN” (for “Milli-Electron-volt Resolution beamLINe”), will create a new state-of-the-art facility for high-resolution angle-resolved photoemission spectroscopy (ARPES). In this first phase of the upgrade, the monochromator was replaced in order to significantly improve the performance of the beamline, readying it for operation after the ALS Upgrade (ALS-U) and creating a foundation for future performance improvements to its photon source and delivery systems.
“The proof is in the pudding,” said Andrew Doran, project manager for the MERLIN upgrade project. “When we could see the light and it was more or less where it was supposed to be, and we could move things to get it where it needs to go, that was exciting,” he said. “For me, as someone building and running beamlines, it’s the milestone where we move from being a construction project to doing commissioning work with the real photons we use for science.”
The bulk of commissioning time so far has involved radiation safety surveys for progressive increases in the ring current and progressive decreases in the undulator gaps. The surveys required the help of ALS floor operators, coincident with the 4th of July holiday. The work was nevertheless completed, thanks to floor operators Matt Abreu, Angelic Lucero, and Revsen Karaalp, who worked after hours and over a weekend to complete the surveys.
With the remaining one day of commissioning time, beamline scientist Jonathan Denlinger, together with a visiting professor on sabbatical from Korea, Yeongkwan Kim, worked around the clock to align one new grating and steer focused light into the ARPES endstation for basic resolution tests. They were even able to perform some ARPES research measurements.
“Most crucially,” said Denlinger, “we now have a baseline understanding of the upgrade operation, which means we can plan summer shutdown activities in preparation for further monochromator commissioning in October and return to user beamtime operations.”
Despite having similar-sounding names, MERLIN and QERLIN are very different beamlines. MERLIN is an ARPES beamline that measures emitted photoelectrons. Beamline 6.0.2, dubbed “QERLIN” (for “Q-rEsolved high ResoLutIoN”), will be used for cutting-edge resonant inelastic x-ray scattering (RIXS)—a photon-in/photon-out technique. Inelastically scattered photons transfer momentum to the sample, and measuring this change in momentum can reveal information about strongly correlated electron excitations. The letter Q represents the momentum transfer vector, and thus, the beamline will be “Q-resolved.”
“It is a very complex system, conceptually new,” said beamline scientist Wanli Yang. “Technically, this system will be the only one in the world for many years, I’m sure, because this is not something easily built.”
The ALS Mechanical Engineering and Technology team is responsible for perhaps the most visually distinctive QERLIN feature: an innovative spectrometer that travels on a large, arc-shaped granite platform to capture photons emitted at various angles. “It is amazing,” said Yang. “All you need to do is punch a number into the computer saying to rotate to this degree, and a high-pressure gas will jack the spectrometer up gently, rotate it into position, and gently land it back.”
The powerful endstation requires a very high performance beamline that produces an x-ray spot on the sample that is tailored to the requirements of the spectrometer. With light now entering the sample chamber, the project is a step closer to commissioning of the endstation.
“This is definitely an exciting time,” said Harold Barnard, who, with Alastair MacDowell, ushered the QERLIN project to this latest milestone. “It lays the foundation for a whole new type of science. So many people came together to make this happen over the last five-plus years. Thank you all for your ideas, hard work, and good company.”
ACKNOWLEDGMENTS
QERLIN TEAM MEMBERS
Core ALS Team
Tony Warwick (retired), Harold Barnard, Alastair MacDowell (retired), Yi-De Chuang (industry), Howard Padmore (retired), Wanli Yang, Yujian Xia
Mechanical Engineering
Haris Muratagic, Adrian Spucces, Lucas Kistulentz, Michael Holmes (industry), Fausto Maciariello (industry), Troy Stevens, Sr. (retired), Tom Rathmann, Will Hutcheson, James Nasiatka, Joseph Tocci, Eric Buice, Joseph Angelo, Mike Kritscher, Robin Armstrong, Maxime Bergeret, Jillian Hiu, Hamish Jacobs, Shawn Rosenthal
Radiation Safety
Stefania Trovati, Taiee Liang (DESY), Maxime Bergeret
Mechanical Technology
Don MacGill, Mike Decool (retired), Vlad Moroz (retired), Monroe Thomas (retired), Dennis Gibson (retired), Plamen Velichkov, Adrian Williams, Troy Stevens, Jr., Krista Williams, Jason Amate, Fritz Minder
Survey and Alignment
Chris Hernikl, Hongyan Zhu, Dan Ellis, Dave Humphries (in memoriam)
Equipment Protection System
Sumanth Borra, Mary Chan, Hanjing Huang
Controls
Martin Keller
Electrical Engineering
Bill Kenney (retired), Rick Lellinger, Aleksandr Hubbard (LLNL), Yossi Ben-nun (LLNL), Curtis Gomez, et al.
Installation and Fabrication
Vinnie Aromin, Elizabeth Titherington
Beamline Review Committee
Andrew Doran, Anders Glans, Tom Scarvie
Floor Operations
Matt Abreu, Angelic Lucero, Haris Mahic, Liz Creager, David Brothers, Maria Aladic, Markton Ross, Liz Creager, Chit Hlaing, Haris Mahic, Sean Nord, Kenneth Osborne, Ed Rim, and Tom Scarvie
MERLIN TEAM MEMBERS
Core ALS Team
Andrew Doran, Daniele Cocco (former staff), Jonathan Denlinger, Yi-De Chuang (industry), Alexei Federov, Sung-Kwan Mo, Yeongkwan Kim
Berkeley Lab Purchasing Department
particularly our dedicated project team buyer Brian Zatkow who orchestrated ~$1M worth of complicated technical bidding and contracts with vendors
Mechanical Technology
Don MacGill, Adrian Williams, Trace Thompson, Plamen Velichkov, Krista Williams, Fritz Minder, Chris Dellingham (former staff), Dennis Gibson (retired), Mike DeCool (retired)
Installation and Fabrication
Vinnie Aromin, Elizabeth Titherington
Electricians
Everett Combs and team
Equipment Protection System
Sumanth Borra, Mary Chan, Greg Mannino
Floor Operations
Matt Abreu, Angelic Lucero, Revsen Karaalp, Haris Mahic, Liz Creager, David Brothers, Maria Aladic, Markton Ross, Chit Hlaing, Sean Nord, Kenneth Osborne, Ed Rim, and Tom Scarvie
Design and Engineering
Lucas Kistulentz, Paul Switzer, Haris Muratagic, Jamie Nasiatka, Troy Stevens, Sr. (retired)
Controls and Integration
Damon English, Martin Keller
Survey and Alignment
Hongyan Zhu, Chris Hernikl, Dan Ellis, Katherine Ray
Optical Metrology
Val Yashchuk, Ian Lacey
Berkeley Lab Riggers
for incredible support for multiple complicated and very high-dollar-value lifts of our specialized equipment in very difficult spaces
Safety Support
for myriad issues small and large from radiation safety to seismic to lead handling to electrical safety
Stefania Trovati, Julie Drotz, Alyssa Brand, Mike Kritscher, Curtis Gomez, Ohmar Sowle
Facility Work Planning Support
Jeff Troutman, Jason Templer
ALS Management
for support and encouragement
Ken Goldberg, Andreas Scholl, Steve Rossi
RSoXS METROLOGY TEAM
ALS Project Lead
Cheng Wang
ALS Beamline 12
Sujoy Roy, Sophie Morley
Beamline Controls
Martin Keller, Damon English
Center for X-Ray Optics (CXRO)
Daniel Santos, Chris Orman, Brandon Vollmer, Jeremy Mentz, Jeffrey Gamsby, Bernhard Luttgenau, Dima Zaytev, Arnaud Allezy, Oleg Kostko, Eric Gullikson, Seno Rekawa
Beamline Review Committee
aCDR, aBDR, aBRR, key enable, and hand-off
Andrew Doran, Tom Scarvie, Stefania Trovati, David Beverly, Douglas Bashaw, Mike Kritscher, Julie Drotz, Don MacGill, Sumanth Borra, Haris Mahic, Matt Abreu
ALS Accelerator
for extra days of beam