When an important piece of equipment failed, staff from across Jefferson Lab came together to make sure the research would carry on
Inside every experimental hall at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility, a crane hangs from the center of the ceiling. These cranes are crucial for the installation and removal of apparatus needed for experiments, where fully assembled experimental systems may reach several stories in height.
“These cranes are used for basically everything,” said Cynthia Keppel, the leader of Experimental Halls A & C at Jefferson Lab. Recently, Keppel experienced just how important these cranes are when the Hall A crane was deemed unusable.
In May of 2021, the Hall A team had just cleared the floor of Hall A to install a piece of equipment, called the Super BigBite Spectrometer (SBS), for the next experiment. The experiment will measure the form factors of nucleons, the collective name for protons and neutrons. Form factors show researchers where charge and magnetization are distributed inside protons and neutrons, which tells them more about where the quarks that make up nucleons are located and how they interact with each other.
To install the SBS apparatus, equipment had to be added to the existing BigBite Spectrometer in Hall A. But before the team could begin bringing in new pieces, Hall A’s ceiling crane began malfunctioning. According to Rusty Sprouse, head of Jefferson Lab’s Facilities Management & Logistics Division, in-depth safety checks revealed some concerning problems with the aged crane.
“We brought in a crane engineer and we literally got video cameras to put on it. And what you see is there’s a lot of movement. And through that exercise, we determined that there’s more movement in the crane than what’s allowable,” he said.
According to Mark Loewus, Jefferson Lab’s manager of crane services, this particular crane had some issues before that were more readily addressed.
“We did everything we could to keep the crane going safely, because we understand the importance of that crane to the work in the hall,” said Loewus. “It was a difficult decision to take the crane out of service.”
This time, the crane would need to be sidelined for a significant amount of time to get to the root of the problem and address it correctly. That meant it couldn’t be used any time in the near future to install the new equipment.
“This is a major experiment installation that was planned to take months using the ceiling crane to install the multiple and various large pieces and parts, and to have them aligned and together for the massive detector systems,” Keppel said. “Without having the crane, we were facing significant delays and possibly not being able to be ready for beam.”
The experiment will use the electron beam from Jefferson Lab’s upgraded 12 GeV Continuous Electron Beam Accelerator Facility (CEBAF). If the SBS apparatus wasn't installed before CEBAF’s beam turns on for experiments, the experimental collaboration could miss out on precious experiment time.
Staying on Track
Installation of a new spectrometer for the SBS apparatus had been slated for this year. This device, which includes huge magnets, will allow the team to measure the form factors of nucleons when paired with a new detector. The completely assembled SBS is about three stories tall.
“You can imagine, if you don’t have a crane, how are you going to get all of that new equipment in place? That’s what we were faced with,” Keppel said.
Instead of accepting delays, staff from across Jefferson Lab’s divisions came together to keep the installation of the SBS on track, said Keppel, who is part of the lab’s Physics Division.
When installing experiments, the Physics Division must work closely with the Facilities Management & Logistics Division, who is responsible for the basic infrastructure of experiments, including operation of the ceiling crane, plus power and water.
“The Hall A team is responsible for the science and the scientific equipment installation,” she said.
As the technical interface for experimental nuclear physics at Jefferson Lab, Walt Akers acts as a go-between for the Physics and Facilities divisions. Akers’ role in the installation of the SBS, as in most similar projects, is to facilitate interactions between the Physics Division and outside organizations to ensure necessary resources are available.
To move forward with SBS, members of the Physics and Facilities divisions determined that instead of the ceiling crane, a mobile crane was needed.
“We went out and contracted for crane service. And, in fact, it worked out really well. It was somebody that all they do is crane operation,” Sprouse said.
However, once Loewus had engaged a local crane service company, which brought its own mobile crane on-site (and got it through the tight fit of the entrance tunnel into Hall A), there was still a lot to figure out.
The Equipment Shuffle
Unlike the ceiling crane, the mobile crane must remain on the floor. That takes up space where equipment might need to be during moving. The mobile crane also can’t reach everywhere in the hall from one spot.
The team had to shuffle the cranes and equipment around to get every piece into place. To do so, the Physics and Facilities divisions had to work hand in hand, carefully changing their originally planned patterns of movements to accommodate the mobile crane. They also had to ensure that the work that each needed to complete could be accommodated in the limited shutdown schedule.
“The halls each have their own work, and they have their own sources. Coordinating work in the halls can be very challenging,” Sprouse said.
Further complicating the process are the potential safety challenges that installing or uninstalling an experiment in a hall can bring. Careful planning is necessary to keep everyone working safe. In addition to large, powerful equipment, experiments like those carried out with the SBS may require components that are kept under high vacuum or high-voltage cables, which could present a potentially dangerous environment. The different installation teams must make sure their daily activities safely overlap.
“There was a lot of training, awareness and work planning,” Keppel said. “It’s a whole lot of logistics, but that’s to protect the safety of people and equipment that represents millions of dollars of DOE investment in the Super BigBite program. It’s nontrivial and the team has worked miracles.”
Counting Down to Beam on Target
Despite the major setback, the Physics and Facilities divisions worked together to safely keep the installation of the SBS apparatus and other high-priority activities on track with the mobile crane.
“I was very pleased with how well Hall A and Facilities staff worked together to resolve conflicts and get the job done,” Akers said. “The more difficult and challenging the work was, the more people had to work together to accomplish the mission. Although there were some strained moments, our staff and users always rose to the occasion to get the job done. It was very rewarding.”
As of the first of September, full installation of the SBS was not quite finished, but it was almost there. Keppel was excited for the experiment to start its run.
“It was kind of a nice big community effort to get us to where we could still install this major experiment,” Keppel said. “It’s what it should be. The mission of the laboratory is to do science, so multiple divisions of the laboratory really mobilized to facilitate this high-profile science project against significant odds.”
Loewus also credits the communication and dedication of the staff to get things done.
“The Hall A team had to rethink their plan of attack on how they were going to build the experiment. They rethought their plan of attack very quickly and incorporated the crane company into their team and worked together flawlessly. Those are the guys that made it happen,” said Loewus.
Keppel feels especially indebted to Jessie Butler, the Hall A Work Coordinator, who had the largest responsibility for the massive planning and coordination effort.
“The real hero of all this is Jessie,” she said.
But it took effort from across the lab to keep progressing science for the immediate experiment, and efforts are already well underway to mitigate impacts on future experiments.
Toward a Permanent Fix
According to Tom Renzo, Jefferson Lab construction manager and a structural engineer, the lab continues to move forward on efforts to repair the crane.
“We had a certified structural engineer company out to look at it. And the main problem they found was that the crane rails were out of round and causing excessive lateral forces at the perimeter,” said Renzo. “What they’re recommending is that we modify how we attach the crane at the perimeter. New ‘floating’ end trucks will be installed that allow for some horizontal movement, preventing those forces from developing. Everybody’s in agreement to do this.”
The repair work will include modifications to the central support for the crane, the end trucks that attach the crane at the perimeter, and other key items. The plan is to conduct much of the work outside of the hall, so as not to interfere with the planned experimental program. The current plan calls for the final work of repairing the crane to begin in the hall near the end of next year.
In the meantime, staff in the Physics and Facilities divisions will continue to coordinate on necessary work tasks to keep the hall in operation safely.
“The goodwill that exists between different groups and departments within our organization is the key to our efficiency and success,” Akers said. “The more that we work together, the more we can achieve.”
By Chris Patrick
Contact: Kandice Carter, Jefferson Lab Communications Office, 757-269-7263, firstname.lastname@example.org