Abstract

We report experiments on the production of ultracold neutrons (UCN) in a converter of superfluid helium coated with fluorinated grease (fomblin). We employed our special technique of window-free extraction of accumulated UCN from the superfluid helium, in which they were produced by downscattering neutrons of a cold beam from the Munich research reactor. The fomblin-coating reduced the time constant for UCN passage through the extraction hole by a factor three compared to our previous experiment employing an uncoated stainless steel vessel. A time-of-flight measurement of the cold neutron spectrum incident on the converter, combined with a gold foil activation, allowed us to determine both the single-phonon and multi-phonon contributions to the UCN production. The UCN production rate is in reasonable agreement with the theoretical expectation.

Details

Title
Ultracold neutrons extracted from a superfluid-helium converter coated with fluorinated grease
Author
Zimmer, O 1 ; Schmidt-Wellenburg, P 2 ; Fertl, M 3 ; H-F Wirth 4 ; Assmann, M 5 ; Klenke, J 5 ; van den Brandt, B 6 

 Physik-Department E18, Technische Universität München, Garching, Germany; Institut Laue-Langevin, Grenoble, France 
 Physik-Department E18, Technische Universität München, Garching, Germany; Institut Laue-Langevin, Grenoble, France; Paul Scherrer Institut, Villigen PSI, Switzerland 
 Physik-Department E18, Technische Universität München, Garching, Germany; Paul Scherrer Institut, Villigen PSI, Switzerland; Paul Scherrer Institut, Villigen PSI, Switzerland 
 Physik-Department E18, Technische Universität München, Garching, Germany 
 Forschungsreaktor München FRM II, Garching, Germany 
 Paul Scherrer Institut, Villigen PSI, Switzerland 
Pages
589-599
Publication year
2010
Publication date
Jun 2010
Publisher
Springer Nature B.V.
ISSN
14346044
e-ISSN
14346052
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2294034397
Copyright
The European Physical Journal C is a copyright of Springer, (2010). All Rights Reserved., © 2010. This work is published under https://creativecommons.org/licenses/by-nc/2.0 (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.