CAMEA—A novel multiplexing analyzer for neutron spectroscopy

Abstract

The analyzer detector system continuous angle multiple energy analysis will be installed on the cold-neutron triple-axis spectrometer RITA-2 at SINQ, PSI. CAMEA is optimized for efficiency in the horizontal scattering plane enabling rapid and detailed mapping of excitations. As a novelty the design employs a series of several sequential upward scattering analyzer arcs. Each arc is set to a different, fixed, final energy and scatters neutrons towards position sensitive detectors. Thus, neutrons with different final energies are recorded simultaneously over a large angular range. In a single data-acquisition many entire constant-energy lines in the horizontal scattering plane are recorded for a quasi-continuous angular coverage of about 60 • . With a large combined coverage in energy and momentum, this will result in a very efficient spectrometer, which will be particularly suited for parametric studies under extreme conditions with restrictive sample environments (high field magnets or pressure cells) and for small samples of novel materials. In this paper we outline the concept and the specifications of the instrument currently under construction. C 2016 AIP Publishing LLC. [http://dx

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

“…This has become known as the Continuous Angle Multiple Energy Analysis (CAMEA) backend [15,16], and is possible due to the transparency of highly oriented pyrolytic graphite (HOPG) at large wavelengths [17]. This type of backend is under construction for the RITA-II cTAS at the PSI [16] and under consideration for the PANDA cTAS [18][19][20] at the MLZ facility [21]. In addition, this setup is to be utilized in the high performance indirect ToF spectrometer BIFROST to be built at the ESS [15].…”

“…A way of increasing the mapping capabilities even further is employing a successive arrangement of vertically scattering analyzer crystals accepting multiple final energies E f in a single θ 2 channel. This has become known as the Continuous Angle Multiple Energy Analysis (CAMEA) backend [15,16], and is possible due to the transparency of highly oriented pyrolytic graphite (HOPG) at large wavelengths [17]. This type of backend is under construction for the RITA-II cTAS at the PSI [16] and under consideration for the PANDA cTAS [18][19][20] at the MLZ facility [21].…”

A combined radial collimator and cooled beryllium filter for neutron scattering

“…The minimum space requirements are especially interesting for wide angle instruments where spatial restrictions apply, e.g. the upcoming generation of multiplexing neutron spectrometers currently developed at different institutes [12,13,14].…”

“…This makes the device especially interesting for the upcoming generation of wide-angle multiplexing spectrometers, e.g. CAMEA [12], BIFROST (formerly CAMEA ESS) [13] and BAMBUS [14], where radial collimation and Be filtering are needed, and spatial restrictions apply. The combined device presented here will be used in the CAMEA spectrometer at PSI.…”

Neutron Larmor diffraction on powder samples

“…The Larmor diffractometers TRISP at the Heinz Maier-Leibnitz Zentrum (Keller et al, 2002;Keller & Keimer, 2015), FLEXX at the Helmholtz-Zentrum Berlin (Groitl et al, 2015) and ZETA at the Institut Laue-Langevin (Martin et al, 2012) were originally designed as three-axis spin-echo spectrometers optimized for the spectroscopy of phonons and spin excitations. These instruments take advantage of the resonant neutron spin-echo technique (NRSE) to define the parallelogram-shaped field regions by radio frequency (RF) spin-flip coils (Golub & Gä hler, 1987;Gä hler & Golub, 1988).…”