A circulating hydrogen ultra-high purification system for the MuCap experiment

V. A. Ganzha, P. A. Kravtsov, O. E. Maev, G. N. Schapkin, G. G. Semenchuk, V. A. Trofimov, A. A. Vasilyev, M. E. Vznuzdaev, S. M. Clayton, P. Kammel, B. Kiburg, M. Hildebrandt, C. Petitjean, T. I. Banks, B. Lauss

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The MuCap experiment is a high-precision measurement of the rate for the basic electroweak process of muon capture, μ-+p→n+νμ. The experimental approach is based on an active target consisting of a time projection chamber (TPC) operating with pure hydrogen gas. The hydrogen has to be kept extremely pure and at a stable pressure. A Circulating Hydrogen Ultra-high Purification System was designed at the Petersburg Nuclear Physics Institute (PNPI) to continuously clean the hydrogen from impurities. The system is based on an adsorption cryo pump to stimulate the hydrogen flow and on a cold adsorbent for the hydrogen cleaning. It was installed at the Paul Scherrer Institute (PSI) in 2004 and performed reliably during three experiment runs. During several months long operating periods the system maintained the hydrogen purity in the detector on the level of 20 ppb for moisture, which is the main contaminant, and of better than 7 and 5 ppb for nitrogen and oxygen, respectively. The pressure inside the TPC was stabilized to within 0.024% of 10 bar at a hydrogen flow rate of three standard liters per minute.

Original languageEnglish (US)
Pages (from-to)485-497
Number of pages13
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number3
StatePublished - Aug 11 2007
Externally publishedYes


  • Circulation
  • Cleaning
  • Detector
  • Gas
  • Hydrogen
  • Mixture
  • Purification

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


Dive into the research topics of 'A circulating hydrogen ultra-high purification system for the MuCap experiment'. Together they form a unique fingerprint.

Cite this