LET, a cold neutron multi-disk chopper spectrometer at ISIS

Bewley, Robert; Taylor, J. W.; Bennington, S. M.

doi:10.1016/j.nima.2011.01.173

Cited by 178 publications

(131 citation statements)

References 15 publications

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“…In such a scenario it is often more convenient to achieve an approximately constant resolution E/E i that is independent of energy. Practical experience at high resolution instruments such as LET [11] and CNCS [12] also shows that at Figure 1. Performance comparison of two moderators for STS that have been optimized to di↵erent specifications.…”

Section: Energy Resolutionmentioning

confidence: 92%

Figure-of-Merit for a Cold Coupled Moderator at the SNS Second Target Station suited for Direct Geometry Inelastic Spectrometers

Ehlers

Sala

Gallmeier

et al. 2018

J. Phys.: Conf. Ser.

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Options for a very cold neutron source for the second target station at SNS F. X. Gallmeier, T. Hügle, E. B. Iverson et al. -The Second Target Station at the ORNL Spallation Neutron Source R K Crawford, R Dean, P Ferguson et al. -High brilliant thermal and cold moderator for the HBS neutron source project Jülich T Cronert, J P Dabruck, P E Doege et al. Abstract.The suite of moderators for the Second Target Station (STS) at the Spallation Neutron Source (SNS) in Oak Ridge is currently undergoing the planning stage at which various options and configurations are being considered. The current plans for the instrument suite include two direct geometry inelastic spectrometers, CHESS and HERTZ, which will receive beam from cold moderators and work mostly in the 1-20 meV incident energy range. CHESS will be a relatively short (wide bandwidth) instrument that is dedicated to studying small samples (⇠ mm 3 ) with coarse energy resolution (2.5 5% of Ei). HERTZ on the other hand will be designed to achieve very good energy resolution, 1 3% of Ei, using a long secondary flightpath with a ⇠ 4 ⇥ 4 cm 2 beam on sample. In this contribution, we will discuss the implications of these design requirements for the optimal moderator pulse width, and for the repetition rate that would be best suited for the spectrometers.

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Section: Energy Resolutionmentioning

confidence: 92%

Figure-of-Merit for a Cold Coupled Moderator at the SNS Second Target Station suited for Direct Geometry Inelastic Spectrometers

Ehlers

Sala

Gallmeier

et al. 2018

J. Phys.: Conf. Ser.

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“…Pulse peak structure at 5 and 20 meV for Coupled moderator; blue, decoupled moderator; green, poisoned decoupled moderator; black and red (font and back surface). Mezei group [9] and becomes a world trend for cold disk chopper instrument such as CNCS [10] at SNS and LET [11] in ISIS. Figure 5 shows an illustration of AMATERAS.…”

Section: En=5mev En=20mevmentioning

confidence: 99%

Present Status of the Materials & Life Science Experimental Facility of J-PARC

Arai¹,

Futakawa²,

Tazaki³

et al. 2015

Proceedings of the 2nd International Symposium on Science at J-Parc — Unlocking the Mysteries of Life, Matter and the Universe

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The facility has resumed since 17th February 2014 after reformation of operation safety system required from the new regulation because of the accident in the Hadron Facility in May 2013. During eight-month shutdown period various hardware components have been improved; such as installation of additional RFQs in Linac to increase its energy to achieve higher power, repairing and replacement on the mercury (Hg) cooling loops of the neutron target, improvement on the cryogenic system for stable operation, etc. In order to mitigate the pitting damage on the Hg-target container we have been injecting helium micro bubbles in the target. The laser Doppler vibrometory showed us that vibration on the proton bombardment has been drastically reduced by the injection. Twenty one instruments have been already installed. Sixteen instruments are operated for user program and four instruments are under either commissioning or construction. Now the experimental hall is almost full with instruments, leaving only 2 ports available for the future use. Operational time for user program in JFY2014 was about 170 days, and we received more than 700 general experimental proposals from users. World-class scientific outputs have been being created in various scientific fields, ranging from Li-battery science to bio-molecular science. Since J-PARC is internationally open for users, we have got experimental proposals from abroad, which are more than 15% of the whole proposals. More than 20% of proposals have come from industries and a half of them are proprietary use. This fact has revealed a new horizon has come in the neutron scattering science in the 21 century.

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“…As one of the world's first direct geometry chopper spectrometers having pulse-shaping operation (other first generation pulse-shaping chopper spectrometers are CNCS at SNS [3] and LET at ISIS [4]), the spectrometer was designed to perform efficient measurements in inelastic and quasi elastic neutron scattering experiments on powders, single crystals and liquids to investigate versatile subjects that were obtained from corrective excitations in crystalline systems to the diffusion of atoms, molecules and ions. AMATERAS initiated its user program in December, 2009.…”

Section: Introductionmentioning

confidence: 99%

Recent Issues encountered by AMATERAS: A Cold-Neutron Disk-Chopper Spectrometer

Nakajima

Ohira‐Kawamura

Kikuchi

et al. 2018

J. Phys.: Conf. Ser.

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Abstract. We report recent issues that have been encountered by AMATERAS, which is a coldneutron disk-chopper spectrometer installed at the Materials & Life Science Experimental Facility at J-PARC. After the last ICANS meeting held in 2014, AMATERAS has continued its user program. On the other hand, the spectrometer has faced several problems, such as a weak shield at the beam dump, failure of one of the chopper disks and many such problems, which we are currently investigating. Further, several instrumental improvements have been performed, such as background reduction, fixing badly designed parts and other such improvements. Our extensive experience obtained in the period of more than 7 years on one of the world's first pulseshaping chopper spectrometers may help other researchers who are operating or planning to construct similar spectrometers.

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LET, a cold neutron multi-disk chopper spectrometer at ISIS

Cited by 178 publications

References 15 publications

Figure-of-Merit for a Cold Coupled Moderator at the SNS Second Target Station suited for Direct Geometry Inelastic Spectrometers

Figure-of-Merit for a Cold Coupled Moderator at the SNS Second Target Station suited for Direct Geometry Inelastic Spectrometers

Present Status of the Materials & Life Science Experimental Facility of J-PARC

Recent Issues encountered by AMATERAS: A Cold-Neutron Disk-Chopper Spectrometer

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