Supplement for LHe in Support of the LEGS Photonuclear Physics Program

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The photonuclear physics group at James Madison University is conducting a program at the Laser Electron Gamma Source (LEGS) located at Brookhaven National Laboratory. The physics program addresses the spin structure of the nucleon and pion production. Central to this program is the Strongly Polarized Hydrogen deuteride ICE (SPHICE) target. This unique, polarized HD target permits measurement of asymmetries and absolute cross sections on the polarized proton, neutron, and deuteron. With proton and deuteron targets, one can measure observables on the neutron and the proton at the same time, reducing effects from systematic uncertainties. The LEGS program, which is entering its final phase, will provide the first such simultaneous measurements of these spin observables. In addition to the cryogenic polarized target, the experiment employs a superconducting, requiring a large consumption of liquid helium. On-campus efforts at James Madison University focus on the distillation of high purity HD for SPHICE target production. Student involvement in operating, developing control and monitoring hardware and software, and optimizing the performance of this facility provides them with valuable experience in low temperature physics and vacuum techniques. This low temperature facility is unique in the world. After preparation on-campus during the academic year, students will spend several weeks during the summer of 2006 at Brookhaven National Laboratory to gain experience in the detector development, data analysis, and instrumentation. Such an off-campus experience, rare at JMU, provides contact with collaborators from around the world. As members of the LEGS-Spin Collaboration, the JMU group is working at BNL with scientists from Italy, France and Germany.