| Autor: |
R. Picker, P. Geltenbort, Erwin Gutsmiedl, Soumen Paul, A.R. Müller, I. Altarev, H.-F. Wirth, S. Materne, F. J. Hartmann, P. Amos, B. Franke, R. Stoepler, A. Mann |
| Rok vydání: |
2009 |
| Předmět: |
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| Zdroj: |
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 611:297-301 |
| ISSN: |
0168-9002 |
| DOI: |
10.1016/j.nima.2009.07.089 |
| Popis: |
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 Δ τ n 0.03 s . 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. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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Full Text from ScienceDirect