CMS Bulletin

MUON DETECTORS: CSC

Great progress has been made on the CSC improvement projects during LS1, the construction of the new ME4/2 muon station, and the refurbishing of the electronics in the high-rate inner ME1/1 muon station. CSC participated successfully in the Global Run in November (GRiN) cosmic ray test, but with just stations +2 and +3, due to the large amount of work going on. The test suite used for commissioning chambers is more comprehensive than the previous tests, and should lead to smoother running in the future.

The chamber factory at Prevessin’s building 904 has just finished assembling all the new ME4/2 chambers, which number 67 to be installed plus five spares, and is now finishing up the long-term HV training and testing of the last chambers. At Point 5, installation of the new chambers on the positive endcap went well, and they are now all working well. Gas leak rates are very low. Services are in good shape, except for the HV system, which will be installed during the coming month. We will then be waiting for a window of opportunity to install ME4/2 chambers on the negative endcap.

Meanwhile, the on-chamber DCFEB electronics production is nearly complete, and 55 of the 72 ME1/1 chambers have been refurbished. Of these, 36 chambers for the positive endcap have been reinstalled. These are being cabled up, and a new LV delivery system (with components called OPFCs, Maratons , Junction Boxes, and Patch Panels) is being commissioned. While a two-chamber “demonstrator” has been successfully commissioned, the rest of the commissioning of the positive endcap is waiting for the services, especially LV, to be completed, and will be done sector by sector for the next month while we are waiting for additional readout electronics to arrive from the vendor. In particular, the off-chamber ODMB electronics board has undergone some delays, but some 10 more pre-production boards are expected this year, and full production is expected in the spring.