MD#2183: Calibration of the IR6 B2 diamond BLMs

In case of an asynchronous beam dump with a fully filled LHC machine, causing ~40 bunches to impact on the movable dump protection absorber (TCDQ), it is expected that all standard ionisation chamber Beam Loss Monitors (IC BLM) around the LHC dumping region in IR6 will be saturated. Diamond Beam Loss Monitors (dBLM) were therefore installed next to the TCDQ downstream of the extraction kickers. These detectors allow resolving losses at a nanosecond timescale and with a dynamic range of several orders of magnitude; thus, allowing to derive the number of nominal bunches impacting the TCDQ. After a first series of calibrations using asynchronous beam dump tests, an experiment was conducted during MD#1182 to demonstrate the possibility of resolving a nominal bunch hitting the TCDQ. During this first MD only the Beam 1 dBLM was calibrated appropriately, a second calibration MD was therefore performed in 2017 for the B2 system. Results from this MD and conclusions regarding dBLM saturation with a top energy nominal bunch are discussed in this note, which also includes results from MD#2930.