Around the Lab
Cryo Pump Isolation Project
The design of a mounting system to isolate the vibration of the OMEGA target chamber cryogenic (cryo) pumps from both the OMEGA target chamber and OMEGA Target Bay floor began in late 2017. The previous arrangement of supporting the cryo pumps consisted of a three-pronged “trident” shaped manifold that was cantilevered off of the target chamber. This manifold did nothing to isolate or attenuate the 240-Hz vibrations generated by the cryogenic pump from the target chamber. For a number of applications, these vibrations were so severe that the cryo pumps needed to be turned off to prevent targets from vibrating at the center of the target chamber. To mitigate problems stemming from the excessive target motion, the Cryo Pump Isolation Project was started in 2017, developing a new system that culminated in the installation of the new Cryo Pump Mounting System on 11 January 2021. The design team included Milt Shoup (Principal Investigator), Jarrett Shamlian (Project Manager and Mechanical Engineering), Tony Agliata (System Engineer), and Bob Peck (Electronics and Controls). Members of the Experimental Operations Group, including Dan Neyland, Tim Davlin, and Matt Maslyn, performed the installation. For the design and implementation of the electrical control systems, the Electrical Engineering (EE) team was led by Robert Peck. Jeff Konzel and Dale Green were the primary EE’s, and Don Farris and Mike Krowl were support EE’s. Victor Kobilansky was the Software Engineer. The Assembly and Integration Group, which includes Chad Abbot, Tom Lewis, Mark Romanofsky, Mark Sickles, and John Szczepanski, built sub-assemblies, cleaned and vacuum tested the assembly in preparation for integration into OMEGA, and provided rigging support during the installation. Additional key members are included in the team photo collage below.
Cryo Pump Isolation Project on 12/17/2020 (left) and 1/11/2021 (right)
Cryo Pump Isolation Project Team:
Chad Abbott, Greg Amos, Josh Brown, Tom Buczek, Tyler Burgett, Tim Clark, Tim Davlin, Don Farris, Dale Green, Tory Hillenbrand, Scott Householder, Tim Illardo Alyson Kittle, Victor, Kobilansky, Jeff Konzel, Mike Krowl, Tom Lewis, Annie Liu, Matt Maslyn, Sam Morse, Dan Neyland, Bob Peck, Mark Romanofsky, Jarrett Shamlian, Walter Shmayda, Milt Shoup, Mark Sickles, Ben Stanley, John Szczepanski, and Jackson Wedow
Not Pictured: Anthony Agliata, Cliff Matthews, and Rob Moshier
The plan involved the design of a cryo pump stack similar to the system installed on OMEGA EP. The OMEGA EP cryo pump stack implemented bellows and elastomer dampeners to isolate the target chamber from the cryo pumps. In addition, the stack is secured to the floor of the OMEGA EP bay floor using a combination of polymer grout and concrete anchors. The polymer grout is employed to help isolate pump vibrations from the concrete floor and into the rest of the facility.
Wall-mounted isolator stack control panel
At project inception in 2017, Project Manager Shamlian, thought “it seemed like a relatively simple design project: Take inspiration from the OMEGA EP pump stack and build a similar one for OMEGA.” However, after a Final Design Review, he and his team members recognized that a massive undertaking was involved:
- The OMEGA Trident Cryo pumps represent some of the most nuclear-activated pieces of equipment in the laboratory. They had been collecting tritium-infused dust for 20 years. Dismantling them safely would require major efforts from the Experimental Operations team.
- The OMEGA Target Bay electronics needed a major overhaul. The Electrical Engineering team would require the pump install maintenance time to replace the existing tangle of a Program Logic Controller (PLC) rack with a tidy wall-mounted version. The rack serves as the backbone of the modular PLC system synchronizing both power and signal communication. It holds together the individual modules within a PLC like the CPU, Communication and Power supply. This PLC rack needed to be strong and designed carefully since it handles the different components of the PLC ecosystem.
- The team would also need to upgrade the junction boxes powering the cryo pumps and replace all the 120-V sensors on the OMEGA target chamber with updated 24-V versions.
With all this new information, the three main groups: Experimental Operations, Mechanical Engineering, and Electronics & Controls Engineering started meeting every other week to develop a comprehensive installation schedule. The installation would require disabling significant elements of the OMEGA Laser System and, as such, it was planned for a ten-day maintenance period in March 2019. However, at the last minute, other important operations interrupted this maintenance period, leaving the installation for the next appropriate downtime a year away in March 2020.
The Project Team continued to determine the schedule and to work out all the remaining details during working group meetings. By March 2020, working in two shifts to complete the project, all of the team members were prepared. They understood the requirements and the timing involved and were ready to move ahead with the installation. Then, the COVID-19 crisis became an official pandemic.
The project was ultimately pushed back to December 2020 and the focus shifted to consider personnel redundancies in case any of the more than 30 team members involved became ill. For example, if a project support team member became disabled due to COVID-19, the project risk assessment team established a mitigation plan:
- Identify bottlenecks in project support team:
– Facility Electricians
– Software - Ensure available support from mechanical and electrical groups to work in two teams
- Provide COVID-19 specific PPE (N95 masks, if available).
As December 2020 approached, everyone was eager and prepared to complete the project. According to Project Manager Shamlian, “We could practically recite the project schedule verbatim.”
The installation process commenced in late December and, after 2 ½ weeks of massive effort from all involved, the new system was commissioned on January 11, 2021. The old pumps were safely removed, new pump parts were installed, and the new PLC, sensors, and power boxes were installed and powered-up. All team members from the three main groups went above and beyond to ensure a safe and timely install.
After the installation was complete, the vibration attenuation of the new system was initially tested. This initial test was used to determine the attenuation of the 240-Hz vibrations from the cryo pumps to surrounding areas and points of interest. When compared to previous levels the new system has reduced the vibrations imparted to the OMEGA target chamber by a factor of 30. Additional studies will be performed to determine the reduction in target vibration and the center of the target chamber.
In addition, the new system has noticeably damped the vibration from the pumps transmitted to the rest of the facility. This is significant for any other projects throughout the facility that require maximum stability while being unable to use active damping systems. Room 5101, for example, is the proposed installation site of the new FLUX project. Floor vibrations in the 240-Hz range in that room now show a noticeable reduction since the installation of the new cryo isolation system. When installed, this will make aligning the hundreds of optics in that system much easier.