Upgrading the Lithium Fluoride Target Holder for Quenching Factor Studies
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Transcript of Upgrading the Lithium Fluoride Target Holder for Quenching Factor Studies
Upgrading the Lithium Fluoride Target Holder for Quenching Factor Studies
Aaron MagnerGrayson RichPhil Barbeau
The 7Li(p,n) ReactionUsed for a
monochromatic, tunable neutron source
Neutrons used for calibration of new low-threshold detectors for neutrino and dark matter experiments (from Lee)
Focus: Proton Beam and Target HealthUse the tandem accelerator at TUNL as
energetic proton sourceDetermine proton flux at target; this is
related to the rate of neutron productionNeutron production can be influenced by
contamination of the target (pump oil, for example)
The Target Holder
Determine composition of target (consider them as surface impurities on the Al backing) via proton back-scattering
Know scattering elements by kinematics
The Target HolderDetermine composition
of target (consider them as surface impurities on the Al backing) via proton back-scattering
Know scattering elements by kinematics; see Backscattering Spectrometry, Chu.
The Runs: Pileup
Evident in runs with higher target current (hundreds of nanoamps) Reduce with baffles?
The Runs: Pileup
Evident in runs with higher target current (hundreds of nanoamps) Reduce with baffles?
The Spectra
Ratios of positions are appropriate for Li, F, and Al.Other contaminants? Possibly Be, B, N, and O.
BeB
NO
Future WorkCalibrate channels to energyAdd baffles to reduce protons scattering from
wall before reaching detectorCool the detectorPut LiF on thin C substrate, separated from
Al, to reduce deep scatters
LiF on C Al
References
Chu, Wei-Kan. Backscattering Spectrometry. 1978. Academic Press, Inc: San Diego, California
Lee, Zhou, “Thick target neutron yields for the 7Li(p,n)Be reaction near threshold,” Nucl. Instr. and Meth. B 152, 1-11 (1999).