Wed·Feb 8, 2017Wednesday·February 8, 2017

1. 01*

   Total kinetic energy release in the fast neutron induced fission of 232Th and 235U

   W. Loveland.🇺🇸 · J. King🇺🇸

   We have measured the total kinetic energy release (TKE), its variance and associated fission product distributions for the neutron induced fission of 232Th and 235U for En = 2 - 90 MeV. The neutron energies were determined on an event by event basis by time of flight measurements with the white spectrum neutron beam from LANSCE. The TKE decreases non-linearly with increasing neutron energy for both systems, while the TKE variances are sensitive indicators of nth chance fission. The associated fission product distributions show the decrease in TKE with increasing beam energy that is due to the increasing probability of symmetric fission, which has a lower associated TKE, and the decreasing TKE associated with asymmetric fission, presumably due to the decreasing importance of the A = 132 shell structures.

   nucl-exnucl-th0 citations
2. 02*

   Radiogenic Neutron Yield Calculations for Low-Background Experiments

   S. Westerdale🇺🇸 · P.D. Meyers🇺🇸

   Nuclear recoil backgrounds are one of the most dangerous backgrounds for many dark matter experiments. A primary source of nuclear recoils is radiogenic neutrons produced in the detector material itself. These neutrons result from fission and $(\alpha ,n)$ reactions originating from uranium and thorium contamination. In this paper, we discuss neutron yields from these sources. We compile a list of $(\alpha ,n)$ yields for many materials common in low-background detectors, calculated using NeuCBOT, a new tool introduced in this paper, available at https://github.com/shawest/neucbot. These calculations are compared to computations made using data compilations and SOURCES-4A

   ↳ physics.ins-detastro-ph.IMnucl-exNucl.Instrum.Meth.A(2017)·63 citations
3. 03*

   The Majorana Demonstrator calibration system

   N. Abgrall · I.J. Arnquist · F.T. Avignone III · A.S. Barabash · F.E. Bertrand · M. Boswell · A.W. Bradley · V. Brudanin · M. Busch · M. Buuck · T.S. Caldwell · C.D. Christofferson and 55 other authors

   The MAJORANA Collaboration is searching for the neutrinoless double-beta decay of the nucleus ${}^{76}$Ge. The MAJORANA DEMONSTRATOR is an array of germanium detectors deployed with the aim of implementing background reduction techniques suitable for a 1-tonne ${}^{76}$Ge-based search. The ultra low-background conditions require regular calibrations to verify proper function of the detectors. Radioactive line sources can be deployed around the cryostats containing the detectors for regular energy calibrations. When measuring in low-background mode, these line sources have to be stored outside the shielding so they do not contribute to the background. The deployment and the retraction of the source are designed to be controlled by the data acquisition system and do not require any direct human interaction. In this paper, we detail the design requirements and implementation of the calibration apparatus, which provides the event rates needed to define the pulse-shape cuts and energy calibration used in the final analysis as well as data that can be compared to simulations.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2017)·32 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.