Session R16: Instrumentation in Nuclear and Particle Physics I

Live

The Muon g-2 experiment E989 at Fermilab measures the anomalous magnetic moment of the muon a$\mu$ with improved precision compared to the Brookhaven E821 experiment, the results of which are in tension with the Standard Model. Determining a$\mu$ requires measurements of both the muon spin precession frequency w$\mu$ and the magnetic field B. The magnetic field is monitored by coordinated nuclear magnetic resonance (NMR) measurements. NMR probes at fixed locations above and below the storage region continuously monitor the field. An in-vacuum trolley with 17 NMR probes infrequently maps the muon storage region, and a special water-based NMR probe provides calibrations for the trolley probes. While the magnetic field of the storage ring is generally changing very slowly, there are additional fast field changes that are happening at time scales shorter than the typical 1ms long NMR signals. This presentation will focus on observed field changes that require special analysis and understanding to determine their effect on the field observed by the stored muons.   

Live

In this talk, I will present a new threshold-free measurement of the quenching factor of NaI(Tl) detectors. Though a handful of measurements of this quenching factor exist, there is disagreement on the precise value of the quenching factor below about 20~keV$_{nr}$, directly in the regions of interest for WIMP direct detection and coherent neutrino-nucleus elastic scattering searches. Additionally, previous measurements are known to have overestimated the quenching factor at low energies due to imperfect knowledge of the trigger efficiency of their NaI(Tl) detector setups. Our measurement seeks to address both of these concerns. We tested multiple NaI(Tl) detectors to search for variations in the quenching factor between detectors. Additionally, we perform a threshold-free measurement by triggering on an array of backing detectors rather than on the NaI(Tl) detector itself.   

Live

Recent developments in radioactive ion-beam facilities allow the production of very neutron-rich nuclei. Away from the line of beta stability towards neutron-rich nuclei, $\beta$-delayed multi-neutron emission is the dominant decay mode. Neutron dEtector with Xn Tracking (NEXT) has been designed to better measure $\beta-$delayed neutron energies. By segmenting the detector along the neutron flight path, NEXT will reduce the associated uncertainties in neutron time-of-flight measurements, improving energy resolution while maintaining detection efficiency. Detector prototypes have been built using segments of n-$\gamma$ discriminating plastic scintillator coupled to position sensitive photomultiplier tubes. Results will be presented from the tests of position-timing correlations and efficiency measurements using neutrons produced from (p,n) and (d,n) reactions.   

Live

Long baseline neutrino experiments, T2K and DUNE, have introduced a novel three-dimensional projection scintillator tracker as part of the near detector system. SuperFGD (for T2K) and 3DST (for DUNE) have eminent ability to detect neutron kinetic energy, on an event by event basis, which is an important missing piece in the GeV level neutrino experiments. Such a scintillator detector consists of 1 cm x 1 cm x 1 cm cube skewered with three XYZ fibers in each cube. Benefited by the fast timing and low readout threshold, neutron kinematic energies in the neutrino interactions can be measured with the time-of-flight technique. In order to fully demonstrate the neutron detection with such a scintillator detector, two prototypes have been exposed to the neutron beam test facility in the Los Alamos National Lab (LANL). The neutron energy spectrum we can resolve is up to 800 MeV. This is the first-ever test of efficiency of a plastic scintillator detector with pseudo-3D readout in a neutron beam. In this talk, the neutron beam test setup for these prototypes will be described and also the neutron detection performance of the scintillator detector will be shown.   

Live

Active-target detectors are becoming a ubiquitous tool for studying reactions both with radioactive and stable beams due to their high efficiency and tracking abilities. We are developing the active-target detector ND-Cube at the University of Notre Dame for studies in nuclear clustering, reactions for nuclear astrophysics, and fusion reactions with radioactive beams. The ND-Cube will also serve as a development platform for Micropattern Gas Detector designs, and detector optimization. Progress on the development of the ND-Cube will be presented including the plans for using a laser system for in-situ drift velocity measurements. The ND-Cube will enable a wide range of measurements that can take advantage of radioactive beams produced at Notre Dame’s Nuclear Science Laboratory in the light mass region.   

Live

Neutrino-nucleus interactions can produce excited nuclear states that can de-excite by emitting particles, including neutrons. Neutrino-induced neutrons (NINs) produced in common gamma shielding material, such as lead and iron, can pose a background for neutrino and dark matter experiments. Additionally, NIN production in lead is the primary mechanism for the Helium and Lead Observatory (HALO) to detect supernova neutrinos, and iron-based supernova NIN detectors have been proposed. Two detectors seeking to study NIN production in lead and iron have been collecting data for several years, using the intense flux of pulsed neutrinos produced by the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). An overview of the detector design and update on the current status will be presented.   

Live

Dual-phase xenon detectors as used in current direct detection dark matter experiments have observed high rates of background electrons in the low energy region. This background negatively impacts the performance of such detectors in various aspects, but its origin has not been well explained. In this talk, we report a systematic investigation of the observed electron background pathologies in the LUX dark matter experiment. Based on the apparent correlation of the dominant background electrons with preceding energy depositions, we classify this background into different categories using the correlation time scale, and discuss possible mechanisms that may lead to such emissions. We will also present the implications of this study to ongoing and future xenon experiments.   

Not Participating

Beyond BES-II, the STAR Collaboration is currently designing, constructing, and installing a suite of new detectors in the forward rapidity region (2.5 $<$ $\eta$ $<$ 4), enabling a program of novel measurements in p+p, p+Au and Au+Au collisions. To fully explore this physics, the forward upgrade needs superior detection capability for neutral pions, photons, electrons, jets and hadrons by adding charged-particle tracking and electromagnetic and hadronic calorimetry to STAR’s capabilities at high pseudorapidity. In light of this upgrade, we will discuss measurements of forward silicon tracker (FST) prototype modules with cosmic rays and an infrared laser to determine whether the modules meet the design requirements on particle detection efficiency and position resolution. Results of the sensor leakage current and capacitance as a function of operating voltage will also be presented.