Sarah Cousineau, Slava Danilov, Marc Doleans, Jeff Holmes, Weishi Wan, Jie Wei
Simrock's group is studying piezoelectric crystal cavity tuning to correct Lorentz detuning. This method employs fast active feedback to adjust the cavity dynamically.
Weishi Wan has begun gathering information on ground motion and superconducting RF, particularly microphonics. Weishi will interface with Danny Mangra on the ground motion work.
Slava Danilov has completed a transverse impedance module for inclusion in ORBIT. He is debugging and benchmarking the module at present. After benchmarking, the model will be applied to the SNS extraction kicker transverse impedance, which Slava estimates to be twice the instability threshold.
Jeff Holmes presented results of recent space charge calculations carried out in collaboration with Alexei Fedotov and Dong-o Jeon. The work involves the behavior of KV beams inside the Montague resonance, which occurs when the horizontal and vertical tunes are equal or nearly equal. Comments and related results follow:
Sarah Cousineau presented results of her initial sequence of beam-in-gap extraction calculations for the SNS ring lattice using the ORBIT code. Using collimator and beam pipe aperture parameters supplied by Nuria Catalan-Lasheras and kicker strength values provided by Nuria and Pete Cameron, Sarah found that with a programmed sequence of kicks designed to sweep through the particle tune spread, the beam was completely removed to the collimator with no loss to the beam pipe in about 50 turns. The assumed beam was at 1 GeV with energy spread of +/-1%, and chromatic effects were included in the calculations to provide tune spread.
Marc Doleans is taking a look at RF control for the SC Linac.
Jie Wei presented a practice run-through of his ASAC talk on interface issues in SNS.