Cool Beams

Hello all, I am Jonathan, and I, along with Edith, are doing research for Dr. Stephenson in the Physics department this summer. Professor Stephenson is part of the MoNA Collaboration, a group of faculty and students from primarily undergraduate institutions, as well as Michigan State where NSCL is located.   The Collaboration built the Modular Neutron Array (MoNA) to study neutron-rich nuclear reactions.

Our research area is nuclear prefragmentation, so looking at the way in which nuclei break apart when they hit each other. When two nuclei hit each other, they go through a two-step process.  First, the two nuclei tear each other apart.  Protons and neutrons are knocked out of both nuclei. These nuclei are, for a brief time, deformed and often have highly unbalanced ratios of neutrons and protons.  Since these new isotopes are unstable and deformed, they quickly decay by throwing out neutrons and gamma rays. How both steps really happen is not well understood since the time scale is so short (less than 0.0000000000000000000001s).  However, understanding this process, called nuclear prefragmentation, is important to creating rare isotope beams used at nuclear research facilities, like the National Superconducting Cyclotron Laboratory (NSCL), where we were last week.

The experiment was to create 9He nuclei in order to study how such a neutron-rich nuclei is put together.  We left for the experiment on Saturday July 8th, and a flight, an incredibly long wait for a rental car, and a drive later, we arrived at the NSCL 18273965954_7a5f463fc2_k

The NSCL is a huge facility that creates beams of rare isotopes for experiments. The NSCL does this by using two cyclotrons to accelerate nuclei to high speeds. This primary beam is then directed onto a target, which produces many different elements and isotopes. It then passes through a series of magnets and wedges of metal which select the correct secondary beam for the experiment. In our experiment, two different secondary beams were used, one of 11Be and one of 12B. The secondary beam is brought into the experimental vault, which is a huge room with tons of really fancy equipment, like the stuff below.file1-1The beam comes in, and strikes the target, and creates lots of new particles, including 9He. After this happens, the charged particles pass through a magnet which directs them into the charged particle detectors. The neutrons that are released are unaffected by the magnet, and continue on to the neutron detectors called MoNA and LISA (Large multi-Institution Scintillator Array). While we were there, we learned a lot, and survived our first overnight experimental shift, but none of it would have been possible without the incredible people. So many people took the time to explain to us what they were doing, why it needed to be done, and let us help them in whatever way possible. Our last day at NSCL, we had the opportunity to go on a tour of the new facility, FRIB (Facility for Rare Isotope Beams) which is being built. We met in the FRIB office trailer, and donned our stylish hard hats, protective eyewear, and safety vests, and went with the rest of the MoNA collaborators into the new facility.  file6

The FRIB facility is the new accelerator which is being built at MSU. The accelerator will be located in a gigantic underground room, which is surrounded on all sides by between four and fourteen feet of solid concrete. The room is more than three hundred feet long, fifty feet wide, and fifteen feet high, and will have between 350 and 400 miles of cables in it. We got to tour the entire facility, except the target room, which is currently closed to the public. The FRIB facility, scheduled to be finished in 2022, will be amazing, and I left with a renewed excitement for physics.



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