Speaker
Description
The SpinQuest experiment at Fermilab uses a polarized solid ammonia
target under a 5T magnetic field, immersed in the liquid helium bath of
an evaporation refrigerator, which lowers the lattice temperature of the
material to nearly 1K. This brings the materials to thermal equilibrium
(TE) polarization state. The TE polarization of the material is enhanced
by radiating a d-band microwave, generated from Extended Interaction
Oscillators (EIO), on the target material at a specific frequency, a process
known as dynamic nuclear polarization (DNP). The output frequency of
the EIO is determined by the size of its resonant cavity, which is controlled
by a high-resolution stepper motor. The level of polarization drifts after
accumulating an intense proton beam from the 120 GeV main injector
over time, which triggers the frequency control system to adjust the EIO
frequency to maintain the maximum level of polarization of the material
as measured by the NMR system. The status of the microwave system
during the ongoing beam commissioning period will be presented.