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BL05: High-Energy Direct-Geometry Inelastic Spectrometer (under construction)

Date: 2021-05-19

Instrument Contact: Dr. TONG Xin

Email: tongxin@ihep.ac.cn

 

The inelastic neutron scattering technique and related neutron spectroscopy techniques play important roles in crucial scientific breakthroughs and discoveries of cutting-edge research in the field of physics, chemistry and material science. It is the most important and direct tool to study the lattice and excitation of condensed matter materials in the range of millielectron - electron volts (meV- eV). Many interesting physical phenomena in this energy region including lattice excitation (phonon), molecular vibration spectrum, magnetic excitation and crystal field excitation, can all be explored by using the technique.

 

The incident energy of the time-of-flight high-energy direct-geometry inelastic neutron scattering spectrometer (HD), ranging from 10 ~1500 meV, covers the majority of the dynamic excitation processes. On Dec. 13th 2017, the Sun Yat-sen University and the Institute of High Energy Physics, Chinese Academy of Sciences signed a memorandum to build the HD instrument at the China Spallation Neutron Source. As the first spectrometer dedicated to dynamics measurement at CSNS, it takes full advantage of high brightness and excellent time-resolved characteristics of neutrons from the decoupled water moderator. The energy resolution is designed to be 3 ~ 5 % and 4 ~10 % in the energy range of 10 ~ 200 meV and 200 ~ 1500 meV, respectively. The detector coverage is -30° ~ 60° (60° ~ 130° after upgrade) horizontally and ± 30° vertically. The day-one sample environments include a 3-300K CCR, a 5-600K CCR and a magnetic field (0 ~ 7 T). The choppers are designed to operate in RRM mode providing several incident energies per neutron pulse. This document presents the design of this instrument along with some mechanical and installation considerations.

 

HD instrument and the parameters of the instrument are presented in Table 0-1.

 

Table 0-1 Technical parameters of the HD instrument

Name

parameters

Moderator

DWM

Energy range

101500 meV

Energy resolution from the vanadium standard

10 ~ 200 meV: 3 ~ 5 %

200 ~1500 meV: 4 ~10 %

Momentum transfer

0.1~41.5 Å-1

Flux at sample

1×106n/s/cm2@100 kW, straight beam

Beam size at the sample

3cm × 3cm

Source to sample

18 m

Sample to detector

2.5 m

Angular coverage

phase Ⅰ(-30°~60°);phase Ⅱ(60°~130°horizontal

-30°30?°vertical