The FlatCone multianalyzer setup for ILL's three-axis spectrometers

CAMEA ESS – The continuous angle multi-energy analysis indirect geometry spectrometer for the European Spallation Source

“…We propose an instrument with 10 concentric arcs of analysers that direct analysed neutrons vertically into detectors, if a neutron scattered from the sample is not at the energy of the first analyser the neutron is transmitted to be analysed by up to nine further analysers working at different final energies. Scattering vertically has been shown not to reduce energy resolution when studying samples of small vertical height (<1 cm) [3]. The increased efficiency of this Multi-Energy Analysis for 10 energies gives a gain factor > 9.1, considering transmission rates.…”

“…The position along the PSD that the neutron is detected determines the angle at which the neutron was scattered from the sample, and knowing the sample orientation the wavevector of the scattered neutrons is determined. To map out excitations in (h, k, ω) of a single crystal a sample rotation scan is performed, in the same way as a scan of a reciprocal plane is produced on a multiplexed spectrometer such as MACS or Flatcone [2,3]. In Fig.…”

“…Within ±1.4 • vertical range of CAMEA, and taking into account transmission rates, we estimate the solid angle gain of CAMEA over Flatcone to be 36 [3], or 23 over MACS at NIST [2]. Comparing CAMEA's flux gain for 2% energy resolution, and the increased solid angle coverage gives a gain factor of ∼ 900 compared to ThALES using Flatcone, provided all detected signal is of use in both cases.…”

“…Direct ToF instruments compensate a low incident neutron flux from using monochromatic pulses, by detecting the scattered neutrons of all energies over a large solid angle in position sensitive detectors. In contrast TAS focus a continuous high flux monochromatic beam of neutrons on a sample but have a low detection coverage of counting neutrons at one final neutron energy at one position, or tens of angles in the case of multiplexed TAS [1][2][3].…”

The upgraded cold neutron triple-axis spectrometer FLEXX – enhanced capabilities by new instrumental options

“…This instrument allows to detect elastic scattering over a continuous Q-range without energy analysis. The FlatCone multianalyzer setup at ILL [11] offers several discrete Q channels and energy analysis which can be chosen at either cold or thermal neutron wavevectors, k F = 1.5Å −1 or k F = 3Å −1 . This option can be used at several three-axis spectrometers at ILL and is tiltable out of the scattering plane as well.…”