Bulletin of the American Physical Society
APS April Meeting 2018
Volume 63, Number 4
Saturday–Tuesday, April 14–17, 2018; Columbus, Ohio
Session K12: Instrumentation |
Hide Abstracts |
Sponsoring Units: DNP Chair: Elton Smith, Jefferson Lab Room: A222-223 |
Sunday, April 15, 2018 3:30PM - 3:42PM |
K12.00001: Noise Studies of Polarimetry Systems for Polarized $^{3}$He Targets Sumudu K. Katugampola, Christopher Jantzi, Vladimir Nelyubin, Gordon D. Cates The NMR technique of adiabatic fast passage (AFP) often plays an important role in monitoring the polarization of $^{3}$He targets polarized using spin-exchange optical pumping. The absolute calibration of such AFP-based polarimetry systems can be accomplished by comparing, either directly or indirectly, with the AFP signals of thermally polarized water. At the low magnetic fields at which spin-exchange polarized $^{3}$He targets are run, however, identifying water signals amidst noise caused by external electromagnetic interferences and microphonics can be challenging. In this talk we will present results obtained from thermally polarized water samples at a field of 36 gauss with a signal-to-noise ratio greater than 10 in a single measurement. The measurements were obtained by using a specially designed NMR apparatus which includes a suspension system to suppress mechanical vibrations and shielding to reduce electromagnetic interference. Our system is part of an effort to improve polarimetry of polarized $^{3}$He targets, and also provides insight into systematic effects related to the use of thermally polarized water for the calibration of low-field AFP-based NMR systems. [Preview Abstract] |
Sunday, April 15, 2018 3:42PM - 3:54PM |
K12.00002: An efficient and cost-effective microchannel plate detector for slow neutron radiography R.T. Desouza, B.B. Wiggins, J. Vadas, D. Bancroft, Z.O. deSouza, J. Huston, S. Hudan, D.V. Baxter A novel approach for efficiently imaging objects with slow neutrons in two dimensions is described. Neutron sensitivity is achieved by use of a boron doped microchannel plate (MCP). The resulting electron avalanche is further amplified with a Z-stack MCP before being sensed by two orthogonally oriented wire planes. Coupling of the wire planes to delay lines efficiently encodes the position information as a time difference. To determine the position resolution, slow neutrons were used to illuminate a Cd-mask placed directly in front of the detector. Peaks in the resulting spectrum exhibited an average peak width of 329 $\mu$m FWHM, corresponding to an average intrinsic resolution of 216 $\mu$m. The center region of the detector exhibits a significantly better spatial resolution with an intrinsic resolution of $<$ 100 $\mu$m observed. [Preview Abstract] |
Sunday, April 15, 2018 3:54PM - 4:06PM |
K12.00003: Construction of an Electromagnetic Calorimeter with Thermal Annealing of Lead Glass in Situ Benjamin Crowe, Tanina Bradley, Caesar Jackson, Seamus Riordan, Albert Shahinyan, Bogdan Wojtsekhowski The construction of a new Electromagnetic Calorimeter is underway for the Super BigBite Spectrometer at Jefferson Lab for the purpose of significantly improving the experimental measurement of the proton electric form factor (GEp-E12-07-109) from the reaction p($\vec$e, e$^{\prime}$ $\vec$p). The well-known problem of radiation damage of lead glass calorimeters from high luminosity experiments such as GEp is being addressed in this design. A novel approach is taken to design a system for continuous thermal annealing in situ to experimental operation. Also, the careful selection of lead glass and light guide materials is found to be very important toward achieving higher signal efficiency and stronger structural strength for the core detector elements. A description of the design and construction of the calorimeter will be presented along with preliminary results from bench tests on some of the subassemblies of the instrument. [Preview Abstract] |
Sunday, April 15, 2018 4:06PM - 4:18PM |
K12.00004: Development of the 30 keV Proton Source and Detector Systems at the University of Manitoba for the Nab Experiment Russell Mammei, Nick Macsai, Wolfgang Klassen, Michael Gericke The ``Nab'' collaboration will perform a precise measurement of the neutron beta decay parameters ``a'' and ``b'', which constitutes a test for physics beyond the standard model.~ The experiment makes use of the fundamental physics cold neutron beamline at the Spallation Neutron Source at the Fundamental Neutron Physics Beam Line.~ This experiment requires very efficient and precise detection of low energy (30 keV) protons with large area Si detectors.~ To this end, a 30 keV proton source has been built at the University of Manitoba (UofM) to characterize the Si detector with respect to a custom large area (150mm x 150mm) microchannel plate detector, with known detection efficiency. During development of the MCP detector, a large area (200 mm diameter) phosphor screen has been employed to characterize the steering mechanism of the proton beam. This talk will introduce the 30 keV proton source at UofM and present the steering mechanism results as measured by the phosphor screen and microchannel plate detector. [Preview Abstract] |
Sunday, April 15, 2018 4:18PM - 4:30PM |
K12.00005: Construction of a Thick-Crystal Neutron Interferometer Using New Fabrication Techniques Benjamin Heacock, AR Young, M Arif, MG Huber, ME Jamer, R Haun, K Hirota, M Kitaguchi, H Shimizu, T Yamamoto, T Hosobata, Y Yamagata, DA Pushin, I Taminiau The construction of a monolithic, thick crystal, ``perfect" silicon neutron interferometer using a ultra-high precision grinding technique and a combination of annealing and chemical etching that differs from the construction of prior neutron interferometers is described. Under these fabrication conditions, the interferometer exhibits an excellent interference fringe visibility of 80\%. The interferometer was tested throughout the post fabrication process, and perturbations to the expected interference signal are found to correspond to subsurface damage that is alleviated through a combination of annealing and chemical etching. These fabrication techniques can be extended to other neutron interferometers or experiments using Bragg-diffracting crystals, where the crystal shape and the integrity of the Bragg planes at the crystal surface are important. [Preview Abstract] |
Sunday, April 15, 2018 4:30PM - 4:42PM |
K12.00006: Increased interference fringe visibility from the post fabrication heat treatment of a perfect crystal silicon neutron interferometer Michael Huber, B Heacock, A Young, M Arif, D G Cory, D A Pushin, R Haun, I Taminiau, D Sarenac, J Nsofini, M E Jamer, T Gnaeupel-Herold We find that annealing a previously chemically etched perfect silicon neutron interferometer at $800~^\circ \mathrm{C}$ dramatically increased interference fringe visibility from 23~\% to 90~\%. The Bragg plane misalignments were also measured before and after annealing using neutron rocking curves, showing that Bragg plane alignment was improved across the interferometer after annealing. This suggests that current interferometers with low fringe visibility may be salvageable and that annealing may become an important step in the fabrication process of future neutron interferometers and other neutron crystal optic elements. This work could lead to decreased need for chemical etching and larger, more exotic neutron interferometer geometries for use in quantum information processes, precision scattering length measurements, and other fundamental physics applications. [Preview Abstract] |
Sunday, April 15, 2018 4:42PM - 4:54PM |
K12.00007: Abstract Withdrawn
|
Sunday, April 15, 2018 4:54PM - 5:06PM |
K12.00008: Verification Datasets from Project 8 Development Laura Gladstone The Project 8 neutrino experiment seeks to determine the absolute neutrino mass scale by measuring the energy of electrons from beta decays, using a novel technique. The technique, called Cyclotron Radiation Emission Spectroscopy (CRES), has been demonstrated at the single-electron scale. In addition to the standard checks for known decay peaks in the energy spectrum, the CRES data can be validated by injecting tones of known frequency, or by observing the CRES emitted by a free electron that is driven by an injected RF wave. The status of these cross-checks will be discussed within the context of planning future development of Project~8. [Preview Abstract] |
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