Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9845757 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2005 | 6 Pages |
Abstract
A new stand-alone system for purification of boil-off nitrogen from 222Rn is described. The purification principle is based on the radon adsorption on charcoal at low temperatures (cryo-adsorption). The device can be attached to ordinary dewars, which are usually used for liquid nitrogen storage or transportation. The measured 222Rn concentration in unpurified boil-off nitrogen is in the range of 0.5 mBq/m3, while the unit described can supply ultra-low background detectors (e.g. gamma spectrometers or dark matter detectors) with gaseous nitrogen of 222Rn specific activity lower by a factor â¼40. The lowest concentration achieved was 12±3 μBq/m3. Using a 100-l dewar it is possible to produce effectively at least 40 m3 of highly pure gas with the available rate between 0.3 and 2.5 m3/h. The nitrogen flux can be set by adjusting the power to an electrical heater placed inside the dewar.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
M. Wójcik, G. Zuzel,