TY - CPAPER AU - Feng, Y. AU - Campell, M.L. AU - Krzywinski, J. AU - Ortiz, E. AU - Raubenheimer, T.O. AU - Rowen, M. AU - Schafer, D.W. TI - Measurment Uncertainties in Gas-Based Monitors for High Repetition Rate X-Ray FEL Operations J2 - Proc. of FEL2015 AB - Thermodynamic simulations using a finite difference method were carried out to investigate the measurement uncertainties in gas-based X-ray FEL diagnostic monitors under high repetition rate operations such as planned for the future LCLS-II soft and hard X-ray FEL's. For monitors using relatively high gas pressures for obtaining sufficient signals, the absorbed thermal power becomes non-negligible as repetition rate increases while keeping pulse energy constant. The fluctuations in the absorbed power were shown to induce significant measurements uncertainties, especially in the single-pulse mode. The magnitude of this thermal effect depends nonlinearly on the absorbed power and can be minimized by using a more efficient detection scheme in which the gas pressure can be set sufficiently low PB - JACoW CY - Geneva, Switzerland SP - 417 EP - 421 KW - FEL KW - undulator KW - simulation KW - detector KW - linac DA - 2015/12 PY - 2015 SN - 978-3-95450-134-2 DO - 10.18429/JACoW-FEL2015-TUP026 UR - http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/tup026.pdf ER -