Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1827027 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2009 | 5 Pages |
Abstract
Marginally trapped neutrons are a major source of systematic errors in storage experiments with ultra-cold neutrons (UCN): their energies slightly exceed the trapping potential and their storage lifetimes are of the same order of magnitude as the neutron β-decay lifetime to be measured. Hence, they have to be removed before the actual neutron storage period starts. For the magneto-gravitational neutron-lifetime experiment PENeLOPE, a novel absorber scheme was proposed; its efficiency to reduce the systematic influence of marginally trapped UCN on the extracted β-decay lifetime value had to be investigated. To this end, the cryogenic material-storage experiment AbEx (Ab sorber Ex periment) was conducted at ILL, Grenoble; neutron-optical properties of storage and absorption materials were investigated. Storage lifetimes shorter than 10 s could be reached for high-energy UCN with the proposed scheme. This translates to a systematic effect on the neutron-lifetime measurement with PENeLOPE of ÎÏn<0.03s. Polyethylene (PE) and titanium were tested as absorber materials. The temperature dependence of their UCN absorbing efficiency was determined to be rather small and connected not with the upscattering cross-section, but probably with surface contaminations.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
R. Picker, I. Altarev, P. Amos, B. Franke, P. Geltenbort, E. Gutsmiedl, F.J. Hartmann, A. Mann, S. Materne, A.R. Müller, S. Paul, R. Stoepler, H.-F. Wirth,