Pfeiffer Vacuum’s ASM 340 helium leak detectors have been chosen by CERN, the Geneva-based European Organization for Nuclear Research, for use with its Large Hadron Collider (LHC).
The particle accelerator LHC has a circumference of 27 km and collides proton or ion beams at nearly the speed of light. The LHC is the largest vacuum installation on Earth. For the accelerated particles to travel in beam lines, ultra-high vacuum (UHV) is essential. To maintain such low pressure, it is crucial to keep the leak rates as low as possible.
The leak detector ASM 340 can detect leaks down to < 5 x 10-13 Pa m3/s. With a built-in backing pump of 15 m3/h, small as well as large volumes can be leak tested. The patent pending functionality makes it possible to start at 100 hPa which is useful for large installations such as the LHC. The leak detector is also very compact, allowing it to be manoeuvered underneath the cryostats and beam lines of the LHC. Helium leak detectors are based on a patented design from Dr Becker at Pfeiffer Vacuum in 1958 who proposed the use of a turbopump as a kind of filter and safety element in front of a mass spectrometer.