Bulletin of the American Physical Society
2017 Fall Meeting of the APS Division of Nuclear Physics
Volume 62, Number 11
Wednesday–Saturday, October 25–28, 2017; Pittsburgh, Pennsylvania
Session KH: Mini-Symposium on Instrumentation for Physics Beyond the Standard Model II |
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Chair: Christopher Crawford, University of Kentucky Room: Marquis B |
Friday, October 27, 2017 2:00PM - 2:12PM |
KH.00001: Precision M{\o}ller Polarimetry William Henry Jefferson Lab’s cutting-edge parity-violating electron scattering program has increasingly stringent requirements for systematic errors. Beam polarimetry is often one of the dominant systematic errors in these experiments. A new M{\o}ller Polarimeter in Hall A of Jefferson Lab (JLab) was installed in 2015 and has taken first measurements for a polarized scattering experiment. Upcoming parity violation experiments in Hall A include CREX, PREX-II, MOLLER and SOLID with the latter two requiring $<$0.5\% precision on beam polarization measurements. The polarimeter measures the M{\o}ller scattering rates of the polarized electron beam incident upon an iron target placed in a saturating magnetic field. The spectrometer consists of four focusing quadrapoles and one momentum selection dipole. The detector is designed to measure the scattered and knock out target electrons in coincidence. Beam polarization is extracted by constructing an asymmetry from the scattering rates when the incident electron spin is parallel and anti-parallel to the target electron spin. Initial data will be presented. Sources of systematic errors include target magnetization, spectrometer acceptance, the Levchuk effect, and radiative corrections which will be discussed. [Preview Abstract] |
Friday, October 27, 2017 2:12PM - 2:24PM |
KH.00002: GEM detector performance and efficiency in Proton Charge Radius (PRad) Experiment Xinzhan Bai The PRad experiment (E12-11-106\footnote{Spokespersons: A.Gasparian(Contact), H. Gao, M. Khandaker, D. Dutta}) was performed in 2016 at Jefferson Lab in Hall B. It aims to investigate the proton charge radius puzzle through electron proton elastic scattering process. The experiment used a non-magnetic spectrometer method, and reached a very small ep scattering angle and thus an unprecedented small four-momentum transfer squared region, $Q^2$ from $2\times10^{-4}$ to $0.06 (GeV/c)^2$. PRad experiment was designed to measure the proton charge radius within a sub-percent precision. Gas Electron Multiplier (GEM) detectors have contributed to reach the experimental goal. A pair of large area GEM detectors, and a large acceptance, high resolution calorimeter(HyCal) were utilized in the experiment to detect the scattered electrons. The precision requirements of the experiment demands a highly accurate understanding of efficiency and stability of GEM detectors. In this talk, we will present the preliminary results on the performance and efficiency of GEM detectors. [Preview Abstract] |
Friday, October 27, 2017 2:24PM - 2:36PM |
KH.00003: GEM Detectors for the DarkLight Phase-1 Experiment Sahara Jesmin Mohammed Prem Nazeer The DarkLight experiment has been proposed to search for a heavy photon A$'$ in the mass range of 10-100 MeV/c$^{2}$ produced in electron-proton collisions. Phase-I of DarkLight has started to take place in 2016 at the Low Energy Recirculator Facility (LERF) at Jefferson Lab. LERF delivered a 100 MeV electron beam onto a windowless hydrogen gas target. The phase-I detector tracks leptons inside the DarkLight solenoid with a set of Gas Electron Multiplier (GEM) detectors, combined with segmented scintillators for triggering. The GEM telescope consists of four $10 \times 10$ cm$^2$ triple layer GEM chambers with 2D readout strips, mounted in a slightly angled fixed frame about 12 cm tall. The GEM data are read out with analog pipeline front-end cards (APV-25) each of which can process 128 readout channels. Each GEM chamber has 250 channels for each coordinate axis, read out with two APVs on each side, resulting in 2000 readout channels for the GEM stack, processed by 16 APVs. One Multi Purpose Digitizer (MPD) module is used to read out all of the 16 APV-25 cards. Details of the design and the readout of the GEM detectors will be presented, as well as discussion of their performance in the August run. [Preview Abstract] |
Friday, October 27, 2017 2:36PM - 2:48PM |
KH.00004: Cherenkov Detectors for Precision Parity Experiments Tyler Kutz Fused silica Cherenkov detectors are ideal for measuring high-rate fluxes of charged particles. The parity program at Jefferson Lab relies on these detectors to measure cross section asymmetries, some of which are predicted to be on the order of tens of parts per billion. Given the required precision of such experiments, it is important that the resolution of these detectors is minimized. Detectors must be optimized while conforming to the physics and engineering constraints of a specific experiment. Two upcoming JLab experiments that will utilize Cherenkov detectors are the Lead (Pb) Radius EXperiment (PREX) and Measurement Of a Lepton-Lepton Electroweak Reaction (MOLLER). PREX will constrain the neutron equation of state by measuring the neutron skin thickness of $^{208}$Pb. MOLLER will test the Standard Model by providing the most precise low-energy measurement of the weak mixing angle. Several detector prototypes have been designed, tested, and simulated to meet the demands of PREX and MOLLER. Presented here is a summary of ongoing work to design state-of-the-art Cherenkov detectors for precision parity experiments. [Preview Abstract] |
Friday, October 27, 2017 2:48PM - 3:00PM |
KH.00005: R{\&}D Toward Ton-Scale HPGXe Neutrinoless Double Beta Decay Experiments Leslie Rogers The NEXT collaboration is developing a sequence of high pressure xenon gas time projection chambers with the aim of creating a ton-scale, very low background neutrinoless double beta decay search.~ ~While most aspects of this technology are easily scalable, some detector elements require R{\&}D in order to be realized on a large scale.~ This talk will describe a new, large-scale test facility under development at the University of Texas at Arlington, which will be used to test electroluminescent gain regions, high voltage feed-throughs and field cage elements for 100kg- and ton-scale xenon gas experiments. [Preview Abstract] |
Friday, October 27, 2017 3:00PM - 3:12PM |
KH.00006: PandaX-III neutrinoless double beta decay experiment Shaobo Wang The PandaX-III experiment uses high pressure Time Projection Chambers (TPCs) to search for neutrinoless double-beta decay of Xe-136 with high energy resolution and sensitivity at the China Jin-Ping underground Laboratory II (CJPL-II). Fine-pitch Microbulk Micromegas will be used for charge amplification and readout in order to reconstruct both the energy and track of the neutrinoless double-beta decay event. In the first phase of the experiment, the detector, which contains 200 kg of 90{\%} Xe-136 enriched gas operated at 10 bar, will be immersed in a large water tank to ensure 5 m of water shielding. For the second phase, a ton-scale experiment with multiple TPCs will be constructed to improve the detection probability and sensitivity. A 20-kg scale prototype TPC with 7 Micromegas modules has been built to optimize the design of Micromegas readout module, study the energy calibration of TPC and develop algorithm of 3D track reconstruction. [Preview Abstract] |
Friday, October 27, 2017 3:12PM - 3:24PM |
KH.00007: Status of R&D toward the nEXO detector Erin Hansen The nEXO experiment, based on the success of the EXO-200 detector, will search for neutrinoless double beta decay of $^{136}$Xe using $\sim5$ tonnes of enriched liquid xenon in a low background time projection chamber. The nEXO Collaboration is engaged in an R&D program to improve charge and light readout, high voltage performance, and xenon purity measurement, as well as identify novel low background materials and develop low-noise in-liquid xenon electronics. This talk will present the status and future prospects of this program. [Preview Abstract] |
Friday, October 27, 2017 3:24PM - 3:36PM |
KH.00008: nEXO: a Tonne-Scale Next-Generation Double-Beta Decay Experiment Samuele Sangiorgio The nEXO Collaboration is designing a next-generation neutrinoless double-beta decay experiment. The nEXO detector will be a 5000kg liquid-xenon time projection chamber (TPC) using isotopically enriched xenon and it is inspired by the very successful EXO-200 experiment. nEXO has been conceived as a discovery experiment thanks to its multi-parameter measurement capability which allows the simultaneous determination of event energy, position, multiplicity, and particle type. This capability, combined with the use of a large homogenous detector volume, allows to optimally determine the backgrounds while exploiting all the signal source mass. Additional background reduction techniques are built in to the detector design through the choice of materials and the use of a layered scheme of passive and active shielding. nEXO will provide a sensitivity on the neutrinoless double-beta decay half-life two orders of magnitude greater than present experiments. In this talk, I will describe the conceptual detector design and discuss the sensitivity reach as derived from a robust background model and recent Monte Carlo simulations. [Preview Abstract] |
Friday, October 27, 2017 3:36PM - 3:48PM |
KH.00009: Study of Charge Build Up in UCN Storage Cell Mark Broering, Josh Abney, Christopher Swank, Bradley Filippone, Weijun Yao, Wolfgang Korsch The neutron EDM collaboration at the Spallation Neutron Source(ORNL) is using ultra-cold neutrons in superfluid helium to improve the nEDM limit by about two orders of magnitude. These neutrons will be stored in target cells located in a strong, stable electric field. Local radiation will generate charged particles which may build up on the target cell walls reducing field strength over time. The field changes need to be kept below 1{\%}, making it necessary to study this cell charging behavior, determine its effect on the experiment and find ways to mitigate this. In order to study this cell charging effect, a compact test setup was designed. Using this scaled down model, charged particles are generated by a $^{\mathrm{137}}$Cs source and the electric field is monitored via the electo-optic Kerr effect. Liquid nitrogen has a much stronger response to electric fields than helium, making it an ideal candidate for first tests. Cell charging effects have been observed in liquid nitrogen. These results along with the experimental technique and progress toward a superfluid helium measurement will also be presented. This research is supported by DOE grants: DE-FG02-99ER41101, DE-AC05-00OR22725 [Preview Abstract] |
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