Power meters and fluorescence intensity monitors as intensity diagnostics in the LCLS-II X-ray instruments

For LCLS-II, we have developed fluorescence intensity monitors and power meters as intensity monitors. The Fluorescence Intensity Monitor (FIM) provides the non-invasive, pulse-by-pulse normalization of experiments. For the LCLS-II instruments, the diagnostic was constructed with an array of four microchannel plate assemblies and four avalanche photodiodes. The diagnostics are being installed in each Kirkpatrick Baez mirror chamber. The noise of the diagnostic will be evaluated against a goal of 1 %. The X-ray power meter delivers average power values. For the LCLS-II instruments, a power meter was selected compatible with high average power. In the LCLS-II instruments, power meters are being installed with each profile monitor in order to evaluate the transmission along the X-ray transport. A calibration of a set of power meters was carried out against a gas monitor detector at FLASH. In addition for all the power meters, a relative calibration was performed with a visible light source. At the endstations, a power meter will determined the pulse energy at the sample.