Design, Implementation and First Measurements with the Medipix Neutron Camera in CMS

TL;DR

The paper reports on the deployment and initial measurements of the Medipix neutron camera in CMS, demonstrating its ability to detect and distinguish particle types, especially neutrons, during LHC operations.

Contribution

First implementation of the Medipix detector for measuring mixed-field radiation and neutron flux in the CMS environment with promising initial results.

Findings

Detected clear signals during LHC runs

Observed different particle types including neutrons

Measured flux rates agree with simulations

Abstract

The Medipix detector is the first device dedicated to measuring mixed-field radiation in the CMS cavern and able to distinguish between different particle types. Medipix2-MXR chips bump bonded to silicon sensors with various neutron conversion layers developed by the IEAP CTU in Prague were successfully installed for the 2008 LHC start-up in the CMS experimental and services caverns to measure the flux of various particle types, in particular neutrons. They have operated almost continuously during the 2010 run period, and the results shown here are from the proton run between the beginning of July and the end of October 2010. Clear signals are seen and different particle types have been observed during regular LHC luminosity running, and an agreement in the measured flux rate is found with the simulations. These initial results are promising, and indicate that these devices have the potential for further and future LHC and high energy physics applications as radiation monitoring devices for mixed field environments, including neutron flux monitoring. Further extensions are foreseen in the near future to increase the performance of the detector and its coverage for monitoring in CMS.