The TOTEM On-line Radiation Monitoring System
F.L.R.Lucas Rodríguez, F.Ravotti*, I.Atanassov, J.Morant, P.Palazzi (CERN)
The TOTEM detectors together with their front-end electronics are located in LHC areas where high radiation levels are expected. To understand the radiation-induced changes on the detector performances and to survey anomalous increases of radiation levels, the Ionizing Dose and the Particle Fluence are monitored during TOTEM operation. This set of information is made available on-line through the TOTEM DCS. The basic unit of the radiation monitoring system is an integrated sensor that hosts 4 types of monitors (RadFETs & p-i-n diodes) connected to the electronics via readout cables. In total, 36 sensors are installed in TOTEM. The one located in the Roman Pots, along the LHC tunnel, sit more than 300m far from the readout electronics. This characteristic makes this system unique with respect to the one implemented for the other LHC experiments. In this article we detail the design of this part of the TOTEM control system based on ELMBs, together with the PVSS control SW architecture and its integration at the supervisory level of the TOTEM DCS. Results of a series of commissioning tests performed at the LHC will be also presented in order to evaluate the performance of the system.