3 research outputs found
Fast Beam Condition Monitor for CMS: performance and upgrade
The CMS beam and radiation monitoring subsystem BCM1F (Fast Beam Condition
Monitor) consists of 8 individual diamond sensors situated around the beam pipe
within the pixel detector volume, for the purpose of fast bunch-by-bunch
monitoring of beam background and collision products. In addition, effort is
ongoing to use BCM1F as an online luminosity monitor. BCM1F will be running
whenever there is beam in LHC, and its data acquisition is independent from the
data acquisition of the CMS detector, hence it delivers luminosity even when
CMS is not taking data. A report is given on the performance of BCM1F during
LHC run I, including results of the van der Meer scan and on-line luminosity
monitoring done in 2012. In order to match the requirements due to higher
luminosity and 25 ns bunch spacing, several changes to the system must be
implemented during the upcoming shutdown, including upgraded electronics and
precise gain monitoring. First results from Run II preparation are shown.Comment: 10 pages, 8 figures. To be published in NIM A as proceedings for the
9th Hiroshima Symposium on Semiconductor Tracking Detectors (2013
Upgraded Fast Beam Conditions Monitor for CMS online luminosity measurement
The CMS beam condition monitoring subsystem BCM1F during LHC Run I consisted of 8 individual diamond sensors situated around the beam pipe within the tracker detector volume, for the purpose of fast monitoring of beam background and collision products. Effort is ongoing to develop the use of BCM1F as an online bunch-by-bunch luminosity monitor. BCM1F will be running whenever there is beam in LHC, and its data acquisition is independent from the data acquisition of the CMS detector, hence it delivers luminosity even when CMS is not taking data. To prepare for the expected increase in the LHC luminosity and the change from 50 ns to 25 ns bunch separation, several changes to the system are required, including a higher number of sensors and upgraded electronics. In particular, a new real-time digitizer with large memory was developed and is being integrated into a multi-subsystem framework for luminosity measurement. Current results from Run II preparation will be discussed, including results from the January 2014 test bea