Sep 25 – 29, 2006
Valencia, Spain
Europe/Zurich timezone

The LHC beam loss monitoring system's data acquisition card

Sep 29, 2006, 9:45 AM
Valencia, Spain

Valencia, Spain

IFIC – Instituto de Fisica Corpuscular Edificio Institutos de Investgación Apartado de Correos 22085 E-46071 València SPAIN


Ewald Effinger (CERN)


The beam loss monitoring (BLM) system is one of the most important elements for the protection of the Large Hadron Collider (LHC). It aims to protect the superconducting magnets from quenches and the machine components from damages, caused by beam losses. The losses are measured with ionization chambers and secondary emission monitors at likely loss locations. About 4000 monitors will be placed along the LHC mounted at the outside of the cryostats. The detectors produce a current proportional to the impacting secondary particle flux. The acquisition cards are placed near the detectors and are exposed to particle irradiation. During the design process of the acquisition cards several irradiation tests have been carried out to verify the radiation tolerance of the chosen components. The large variations of the quench levels with the beam energy and the particle loss duration, require the acquisition and digitalisation of the detector currents over eight orders of magnitude. The high dynamic range is covered by a current to frequency converter (CFC), which measures currents between 10 pA and 1 mA. An additional ADC measures the output voltage of the CFC to improve the data acquisition cards resolution. The signals of eight detectors are digitalised on one acquisition card. The data, together with card status information, are transferred to the processing card via two optical links.

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