Neutronic studies of the coupled moderators for spallation neutron sources

• 来源期刊: 中国物理（英文版）
• 关键词: neutronic studies spallation neutron sourec moderator
• 年，卷（期）: 2005,（3）
• 页码范围: 500-504
• 页数: 5页
• 语种: 英文

摘要

We investigate the neutronic performance of coupled moderators to be implemented in spallation neutron sources by Monte-Carlo simulation and give the slow neutron spectra for the cold and thermal moderators. CH4 moderator can provide slow neutrons with highly desirable characteristics and will be used in low-power spallation neutron soureces. The slow neutron intensity extracted from different angles has been calculated. The capability of moderation of liquid H2 is lower than H2O and liquid CH4 due to lower atomic number density of hydrogen but we can compensate for this disadvantage by using a premoderator. The H2O premoderator of 2cm thickness can reduce the heat deposition in the cold moderator by about 33% without spoiling the neutron pulse.