Two Year Difference
May 19, 2014


On May 19, 2012, we held an Open House; on Saturday, May 17, 2014, we held an Open House; it’s a habit.

And what a day we had on Saturday! The weather was perfect. The extent to which we are able to open the lab is a major surprise for many visitors. They arrive with the expectation that maybe we open one building with displays. Instead, they find themselves getting into the accelerator, the Central Helium Liquefier, and ALL the experimental halls. The semi-official estimate from Kandice Carter is that the total number of visitors was between 5,500 and 6,500, this estimate was done in conjunction with the Newport News police who have some experience in this area. Tom Oren had his own count of visitors to the North and South Linacs, in excess of 1,100 in each case. And the safety number was zero, we did not even record a bee sting!

What I always find impressive is the depth of the questions that are posed. You find people who can really appreciate the way that the arcs work with different strength magnets but that the different energies travel the linac together. For me, when I came here, it was one of the things I found quite tricky, but they seemed to pick it up quite quickly. When discussing the microwave guides feeding to the cryomodules, I found myself being asked what are microwaves used for on  naval ships? The questioner recalled seeing notices up and down his ship “waveguides don’t knock!”  I could not answer that question. One woman with boy and girl twins was over the moon because her son, who wanted to be a physicist, could get to see inside the Central Helium Liquefier. She had an Italian accent and was from Milano. I tried my three Italian words on her and then told her that the Director of Frascati is a friend of mine. She and her son were fascinated with the possibility that the Italian National Labs have a similarity to Jefferson Lab.

I am confident that nearly everyone associated with Jefferson Lab enjoyed such exchanges. I know I got a number of comments and a few e-mails saying how well our teams explained the physics and the apparatus. You might also be interested to know that there were ringers in the crowd; Steve Meador, the Acting Head of the Office of Project Assessment in DOE-SC, came down from D.C. unannounced; we met in the South Linac and his praise for the event was high.

But what about someone who was making a repeat visit after 2012? What did that person see? Was it the same?  Not at all! In two years, we have transformed the Lab!

New in the Test Lab Addition, Anne-Marie Valente’s team were using some of the past displays, the air-pulse accelerator for instance, but the place is dramatically different. A refurbished cryomodule from the Free-Electron Laser was on display funded by the Commonwealth of Virginia. The facility overall has received  two LEED gold awards, as well as several other awards, which are testimony to the team-work between architects and future occupants to find solutions for the multi-purposes foreseen for the Technology and Engineering Development Facility and the Test Lab Addition.

New is the equipment in the second Central Helium Liquefier; two years ago, there was the shell of the building with some of the equipment. But now, we have a tandem Central Helium Liquefier that has supported accelerator operations since the fall. We have discussions about how long it will take to understand the many subtleties of operating the system, but the basic functionality has been demonstrated.

New in the accelerator, there are ten arcs; of those, nine were removed, rebuilt, re-measured and reinstalled, and one arc is brand new. The injector has been significantly reworked. The linacs each have five new cryomodules. We have demonstrated slightly more than 2.2 GeV in a single pass, more than 6 GeV in three passes, and have extracted CW beam into Hall A, where electron scattering spectra were measured in the large superconducting spectrometers. We have demonstrated 10.5 GeV in 5.5 passes and have extracted low intensity pulsed beam and transported the beam to the Hall D Tagger dump. Thus electrons have traversed all of the “12 GeV" machine. This major commissioning success came just more than a week ago, in time to allow visitors into the accelerator.

New in the Halls? The Hall A equipment is being readied to kick off the 12 GeV physics program.

New in Hall D is essentially the complete GlueX experiment. All the major detectors are there in and around the superconducting solenoid, which has been tested and whose refrigerator has been almost rebuilt. 

New in Hall C? The time-lapse film showed it all: the Q-weak spectrometer and the Short Orbit Spectrometer have been removed, a flood was drained and cleaned, and the carriage for the new Super High Momentum Spectrometer, along with a new detector hut, has been built, and the power supplies are being installed along with the new magnet yokes.

New in Hall B? Most of CLAS 6 was removed. New metalwork platforms were installed at the front end of the Hall and several pieces of the forward carriage, including the preshower detector and the Forward Time of Flight detectors, have been installed.

Reflect a moment; what a difference two years make!