The JESSICA Moderator System: A Cryogenic Moderator System

Article type: Research Article

Authors: Stelzer, H. | Barnert-Wiemer, H. | Bayer, N.

Affiliations: Forschungszentrum Jülich GmbH, Zentralabteilung Technologie, D-52425, Jülich, Germany

Note: [] Corresponding author. Tel.: +49-2461-61-3680. Fax: +49-2461-61-6816. E-mail: [email protected]

Abstract: Jülich Experimental Spallation Target Set-up In COSYArea (JESSICA) is a full-scale model of the target-reflector-moderator system for the European Spallation Source (ESS), which has been built up at the COSY accelerator in the research centre Juelich. JESSICA has been designed for prototyping experiments for the ESS and to validate simulation methods concerning the transport and interaction of particles as well as to optimize the technical layout of the target-reflector-moderator system and to compare the results by using different moderator materials. This year JESSICA will become operational with one cryogenic moderator and one ambient below the target, and two ambient moderators above it. For the cryogenic moderator, different moderator materials will be used. (a) Liquid hydrogen (b) Solid methane as a block (c) Solid methane pellets surrounded by liquid hydrogen. The engineering design of JESSICA, including the cryogenic moderator system and safety aspects, will be discussed.

Keywords: European spallation source, JESSICA, Cryogenic moderator, Target-reflector-moderator system

DOI: 10.1080/1023816031000100950

Journal: Journal of Neutron Research, vol. 11, no. 1, 2, pp. 99-105, 2003