Bulletin of the American Physical Society
2013 Fall Meeting of the APS Division of Nuclear Physics
Volume 58, Number 13
Wednesday–Saturday, October 23–26, 2013; Newport News, Virginia
Session CJ: Instrumentation I |
Hide Abstracts |
Chair: Christopher Crawford, University of Kentucky Room: Blue Point I |
Thursday, October 24, 2013 8:30AM - 8:42AM |
CJ.00001: TRINAT apparatus for measurements of correlations from the beta decay of magneto-optically trapped polarized alkali atoms Alexandre Gorelov, J.A. Behr, L. Kurchaninov, K. Olchanski, S. Smale, S. Behling, D. Melconian, B. Fenker, M. Mehlman, P.D. Shilding, M. Anholm, D. Ashery, G. Gwinner Measurements of correlations from beta decay of highly polarized atoms from MOT requires a fast transition between trapping and polarization/measurement cycles to reduce an unwanted expansion of decaying atoms. To achieve this, we have developed an apparatus employing AC MOT, which required placing high-current and low-inductance coils of magnetic quadrupole inside the stainless steel vacuum vessel and allowed us to reduce a time gap between trapping and measurement cycles (the quadrupole magnetic field in the trap region has to become less than 50mG) to less than 100$\mu$s. The nuclear detection system consists of an electrostatic spectrometer of recoiling ions and shake-off electrons with MCP based detectors in back-to-back geometry as well as two scintillator based $\beta-$telescopes, normal to the MCP-MCP axis. This system allowed us to successfully measure the beta asymmetry in the $\beta^+$ decay of polarized $^{37}$K atoms with significantly reduced backgrounds. Time-varying magnetic field from the AC MOT and stationary guiding electric field allowed us to probe the energy distribution of the shakeoff electrons in the range 5$-$30eV. [Preview Abstract] |
Thursday, October 24, 2013 8:42AM - 8:54AM |
CJ.00002: Detector set-up for measuring the e-nu correlation in He-6 beta decay Yelena Bagdasarova, Alejandro Garcia, Kevin Bailey, Xavier Flechard, Ran Hong, Andreas Knecht, Etienne Liennard, Peter Mueller, Oscar Naviliat-Cuncic, Tom O'Connor, Derek Storm, Erik Swanson, Frederik Wauters, Will Williams, David Zumwalt Our experiment aims to extract the $e-\bar{\nu_{e}}$ angular correlation by measuring the momenta of the betas and the TOF of the $^6Li$ recoil ions in the decay of $^6He$. In my talk, I will provide an overview of the detectors within our trapping volume, including the electric field system used to guide the recoil ions toward the microchannel plate + delay line detector. Using example data and simulation, I will discuss some of the high voltage application issues that arose during testing and how we remedied them. [Preview Abstract] |
Thursday, October 24, 2013 8:54AM - 9:06AM |
CJ.00003: Measurement of soft X-rays from neutron radiative decay Thomas Gentile In the RDK II experiment, photons with energies between 5 keV and the 782 keV endpoint from neutron radiative decay were detected using an array of 12 bismuth germanate (BGO) crystals, each coupled to an avalanche photodiode (APD). Since the experiment was performed in the bore of a superconducting magnet, APDs were preferable to photomultiplier tubes. Simultaneously we detected soft X-ray photons in the energy range from 0.3 keV to 20 keV with three larger APDs. We found that for soft X-ray detection near 77 K the APD must be oriented with its electric field parallel to the magnetic field, otherwise there is substantial distortion of the response. Extraction of the soft X-ray radiative decay spectrum required studies of the response of the APD. We performed measurements of the APD response for monochromatic X-ray beams between 0.35 keV and 1.5 keV on the U3C beam line at the NSLS at BNL. The data were used to model the APD pulse height spectrum as a function of X-ray energy using a profile for the depth-dependent efficiency for collection of electron-hole pairs. This model was validated using a continuum spectrum at the NIST SURF III. We will describe the construction of the detector, discuss the results of the magnetic field, BNL and SURF studies, and present preliminary results of determination of the radiative decay spectrum in the soft X-ray range. [Preview Abstract] |
Thursday, October 24, 2013 9:06AM - 9:18AM |
CJ.00004: Construction of low current 30 keV proton accelerator for detection efficiency studies Americo Salas Bacci, Stefan Baessler, Aaron Ross, Nicholas Roane, C.J. Whitaker We have constructed a small ion source and proton accelerator at UVA. This accelerator is needed for the characterization of the detection efficiency of a large area, thick, 127-hexagonal segmented Silicon detector for the neutron beta decay ``Nab'' experiment that will be carried out at SNS, Oak Ridge National Laboratory in search of physics beyond the standard model. We will present the design, simulations, operation, and detection of 30 keV H$^{+}$ and H$_{2}$$^{+}$, as well as our efforts to stabilize and correlate both ion currents. [Preview Abstract] |
Thursday, October 24, 2013 9:18AM - 9:30AM |
CJ.00005: A Superfluid Film Burner for the nEDM Experiment James Maxwell A planned measurement of the neutron electric dipole moment (nEDM) to $10^{-28}$ e$\cdot$cm using the Golub--Lamoreaux method presents complex cryogenic challenges. One such hurdle is the injection of $^3$He from a polarized atomic beam source into a liquid $^4$He bath while maintaining the temperature gradient from the cold bath to the warm beam source and minimizing the vapor above the bath. The feasible temperature range for the experiment falls around 400 mK and is constrained from below by the achievable magnetic field gradients, and above by the spin relaxation time of $^3$He and rate of ultracold neutron up-scattering. The superfluid behavior of $^4$He below 2.1 K means superfluid film will tend to climb, or ``creep,'' up the sides of the beam tube to reach the warmer space above, creating vapor, resulting in convection and scattering of incident $^3$He. To stop the superfluid film creep and contain the vapor, a ``film burner'' is under development by the nEDM collaboration. We will describe the effort toward developing a suitable film burner for nEDM, and show preliminary results of a prototype film burner in operation. [Preview Abstract] |
Thursday, October 24, 2013 9:30AM - 9:42AM |
CJ.00006: Measurement of the response of carbon fiber drift tubes to high energy neutrons (E$<$800 MeV) Robert Pattie A next generation experiment to measure the neutron-antineutron oscillation time will require a large area vertex tracker which is insensitive to the possible flux of high energy (up to 1 GeV) neutrons generated in the spallation cold neutron source. A neutron-antineutron annihilation event would most likely appear as 4 to 5 pions with total energy of $\sim$2 GeV originating on the annihilation target. Several detector technologies exist are capable of reconstructing a multi-pion event to within 1 cm of the annihilation target, which would allow for high efficiency background rejection. However, it is possible for high energy neutrons from the spallation source to generate background events that mimic the annihilation signal. These backgrounds can be mitigated by shielding the source and building the vertex track with detectors that are insensitive to high energy neutrons. The NNBarX collaboration has begun a series of studies at the WNR spallation neutron target at LANSCE to characterize the response of possible vertex detectors. We present results on the efficiency of Ar/Ethane and Ar/Ethane/CF$_4$ filled carbon fiber drift tubes for neutrons with energy up to 800 MeV. [Preview Abstract] |
Thursday, October 24, 2013 9:42AM - 9:54AM |
CJ.00007: A Measurement of Underground Cosmic Neutron Fluxes with SciBath Remington Thornton Designed as a neutrino prototype detector, SciBath is an 80 liter liquid scintillator detector with a three dimensional grid of 768 wavelength-shifting fibers and is sensitive to neutrons above 10 MeV. A data run at Fermilab near the MINOS detector (100 m underground) in fall of 2011 was taken to demonstrate neutral particle detection. An overview of the detector performance during this run, the measured cosmic neutron flux, and comparisons to predictions will be presented. [Preview Abstract] |
Thursday, October 24, 2013 9:54AM - 10:06AM |
CJ.00008: Understanding the effect of atmospheric Density on the Cosmic Ray Flux Variations at the Earth Surface Xiaohang Zhang, Mathes Dayananda, Carola Butler, Xiaochun He While the true impact of cosmic rays on the earth climate change is currently far from conclusive, continued efforts of long-term monitoring of cosmic ray flux variations are imperative. This study also requires a quantitative understanding of the influence of atmosphere air density fluctuations to the cosmic ray flux. In this talk, we present the study of the dependence of cosmic ray muon and neutron flux on the atmospheric density variations using Geant4 simulation package. The results are compared with the neutron flux measurements in Oulu, Finland and the muon flux measured in Atlanta, US. [Preview Abstract] |
Thursday, October 24, 2013 10:06AM - 10:18AM |
CJ.00009: ABSTRACT WITHDRAWN |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700