1. MSE thermal birefringence and shot to shot reproducibility
Motivation:
MSE has poor reproducibility in q measurements
Last campaign we determined this was caused by birefringence in L2 from temperature changes throughout the run day ( )
Bench experiments support this hypothesis
, Alcator Ideas Forum: MSE reproducibility, B. Mumgaard, S Scott, J. Ko, S Shiraiwa

2. Thermal Management Actions taken
MSE thermal shield
L2 mount O-ring seat
Actions taken
New L2 mount to thermally isolate lens from the MSE canister
New heat shield for temperature control of entire canister
Proposal
A few identical shots throughout a run day to check reproducibility
Preferably run days with significant RF heating for worst possible thermal environment
, Alcator Ideas Forum: MSE reproducibility, B. Mumgaard, S Scott, J. Ko, S Shiraiwa