Neutron time-of-flight scattering
Encyclopedia
In Neutron time-of-flight scattering, a form of inelastic neutron scattering
, the initial position and velocity of a pulse of neutron
s is fixed, and their final position and the time after the pulse that the neutrons are detected are measured. By the principle of conservation of momentum, these pairs of coordinates may be transformed into momenta and energies for the neutrons, and the experimentalist may use this information to calculate the momentum and energy transferred to the sample. Inverse geometry spectrometers are also possible. In this case, the final position and velocity are fixed, and the incident coordinates varied.
Time-of-flight scattering can be performed at either a research reactor
or a spallation
source.
Existing time-of-flight spectrometers at research reactors:
Inelastic neutron scattering
Inelastic neutron scattering is an experimental technique commonly used in condensed matter research to study atomic and molecular motion as well as magnetic and crystal field excitations....
, the initial position and velocity of a pulse of neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
s is fixed, and their final position and the time after the pulse that the neutrons are detected are measured. By the principle of conservation of momentum, these pairs of coordinates may be transformed into momenta and energies for the neutrons, and the experimentalist may use this information to calculate the momentum and energy transferred to the sample. Inverse geometry spectrometers are also possible. In this case, the final position and velocity are fixed, and the incident coordinates varied.
Time-of-flight scattering can be performed at either a research reactor
Research reactor
Research reactors are nuclear reactors that serve primarily as a neutron source. They are also called non-power reactors, in contrast to power reactors that are used for electricity production, heat generation, or maritime propulsion.-Purpose:...
or a spallation
Spallation
In general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection or vaporization of material from a target during impact by a projectile...
source.
External links
Existing time-of-flight spectrometers at spallation sources:- LRMECS and HRMECS at Argonne National LaboratoryArgonne National LaboratoryArgonne National Laboratory is the first science and engineering research national laboratory in the United States, receiving this designation on July 1, 1946. It is the largest national laboratory by size and scope in the Midwest...
- Pharos at LANSCE's Lujan Center at Los Alamos National LaboratoryLos Alamos National LaboratoryLos Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...
- MAPS, MARI, HET *MERLIN and LET at the ISIS neutron sourceISIS neutron sourceISIS is a pulsed neutron and muon source. It is situated at the Rutherford Appleton Laboratory on the Harwell Science and Innovation Campus in Oxfordshire, United Kingdom and is part of the Science and Technology Facilities Council...
- ARCS , CNCS, and SEQUOIA at the Spallation Neutron SourceSpallation Neutron SourceThe Spallation Neutron Source is an accelerator-based neutron source facility that provides the most intense pulsed neutron beams in the world for scientific research and industrial development...
Existing time-of-flight spectrometers at research reactors:
- DCS and FCS at the NIST laboratories in Maryland.
- IN4, IN5, and IN6 at the Institut Laue-LangevinInstitut Laue-LangevinThe Institut Laue–Langevin, or ILL, is an internationally-financed scientific facility, situated in Grenoble, France. It is one of the world centres for research using neutrons...
- TOFTOF at the Forschungsneutronenquelle Heinz Maier-Leibnitz
- SKAT-EPSILON at the Joint Institute for Nuclear Research (JINR)Joint Institute for Nuclear ResearchThe Joint Institute for Nuclear Research, JINR , in Dubna, Moscow Oblast , Russia, is an international research centre for nuclear sciences, with 5500 staff members, 1200 researchers including 1000 Ph.D.s from eighteen member states The Joint Institute for Nuclear Research, JINR , in Dubna, Moscow...