The GAMS4 Flat Crystal Facility

Published

January 1, 2001

Author(s)

Ernest G. Kessler, Maynard S. Dewey, R Deslattes, Albert Henins, H G. Borner, M Jentschel, H Lehmann

Abstract

A high-resolution flat crystal gamma-ray facility, GAMS4, has been constructed at the high flux reactor at the Institut Laue-Langevin (ILL), Grenoble, France. The facility is located at the exit of a through-tube equipped to place sources in a neutron flux of {approximately equal to} 5.5 x 10¹⁴ n cm^-2s^-1. Considerable care has been exercised to provide a precision gamma-ray metrology station including vibration isolation, temperature control, environmental monitoring, background suppression, and remote and automatic spectrometer control. The diffraction angles are controlled and measured interferometrically and absolute angle calibration is established with a relative uncertainty of {approximately equal to} 3 x 10^-7. The crystals are nearly perfect specimens of Si and Ge whose lattice spacings are measured in meters and have a relative uncertainty of {approximately equal to} 5 x 10^-8. The resolution obtained with this facility closely approaches dynamical diffraction predictions. Examples of measurements performed using this facility include 1) absolute wavelengths standards and neutron binding energies, 2) lifetimes of nuclear excited states, 3) determination of interatomic potentials, and 4) crystal structure factors. GAMS4 is a scheduled ILL instrument with beamtime being awarded through the ILL proposal process.

Citation

Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors and Associated Equipment

Volume

457

Issue

No. 1-2

Pub Type

Journals

Keywords

crystal diffraction, gamma-ray spectroscopy, gamma-ray wavelengths, interferometers, life-times, neutron capture

Citation

Kessler, E. , Dewey, M. , Deslattes, R. , Henins, A. , Borner, H. , Jentschel, M. and Lehmann, H. (2001), The GAMS4 Flat Crystal Facility, Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors and Associated Equipment (Accessed October 13, 2025)