The LHC beam loss measurement system

Abstract

An unprecedented amount of energy will be stored in the circulating beams of LHC. The loss of even a very small fraction of a beam may induce a quench in the superconducting magnets or cause physical damage to machine components. A fast (one turn) loss of 3 · 10 -9 and a constant loss of 3 · 10 -12 times the nominal beam intensity can quench a dipole magnet. A fast loss of 3 · 10 -6 times nominal beam intensity can damage a magnet. The stored energy in the LHC beam is a factor of 200 (or more) higher than in existing hadron machines with superconducting magnets (HERA, TEVATRON, RHIC), while the quench levels of the LHC magnets are a factor of about 5 to 20 lower than the quench levels of these machines. To comply with these requirements the detectors, ionisation chambers and secondary emission monitors are designed very reliable with a large operational range. Several stages of the acquisition chain are doubled and frequent functionality tests are automatically executed. The failure probabilities of single components were identified and optimised. First measurements show the large dynamic range of the system. Large Hadron Collider Project AbstractAn unprecedented amount of energy will be stored in the circulating beams of LHC. The loss of even a very small fraction of a beam may induce a quench in the superconducting magnets or cause physical damage to machine components. A fast (one turn) loss of 3 · 10 −9 and a constant loss of 3 · 10 −12 times the nominal beam intensity can quench a dipole magnet. A fast loss of 3 · 10

LHC and HL-LHC: Present and Future Radiation Environment in the High-Luminosity Collision Points and RHA Implications

“…The LHC beam loss monitoring (BLM) system [8], [9] is based on ionizing chambers and has the main purpose of preventing the superconducting magnets from quenching as well as of protecting the machine components from damage. About 4000 of them are installed in the LHC.…”

Possibilities for On-line Detector Connectivity Checks in Beam Loss Monitoring Systems

“…Fig. 1 An ionization chamber without its outer shell [2]. Notice the stack of parallel electrodes collecting the charges separated by the bias voltage.…”

A Distributed System for Radiation Monitoring at Linear Accelerators

“…Regular beam losses have the same time structure as the main beam. However, additional, irregular beam losses can occur unexpectedly [4], [10], [11]. The radiation level in the electron linear accelerator is generally low, therefore in some cases it could be difficult to measure.…”