Session Z12: Instrumentation (DNP)

GEM Detector Construction for DarkLight Phase 1C

DarkLight Phase 1C was proposed as a dedicated search to verify the proclaimed 17-MeV fifth-force carrier observed in the emission of di-leptons from excited Be. The setup is based on two magnetic spectrometers to detect the lepton pair, instrumented with customized large area GEM detectors for tracking. 
A novel GEM construction technique is used where all layers are stretched and assembled mechanically within a double frame. The readout will be based on APVs and MPDs. The key features of these detectors allows them to be used very flexibly in high-rate environments for high-resolution charged particle tracking. The present status of the construction, design features and expected performance of the GEM detectors will be discussed.
  

Characterization of a low background counting facility at Kimballton Underground Research Facility

We report on the characterization of a new low-background counting facility at the Kimballton Underground Research Facility in Virginia. The facility consists of a shielded, high-purity germanium detector deployed at a depth of approximately 300 meters water equivalent. Exploiting gamma ray spectroscopy in a low cosmic-ray flux environment facility can be used to screen materials for applications in low-background experiments, such as neutrinoless double-beta decay or dark matter searches. We describe the performance of a GEANT4 simulation, which we use for geometrical efficiency and sample self-shielding calculations and present the sensitivity to isotopes of common interest --- ²³⁸U, ²³²Th and ⁴⁰K. As the background goals in next-generation rare decay searches become ever-more stringent, high-sensitivity radio-purity screening facilities will continue to play an important role in supporting this science.   

Calibration of Polarimetry Systems for Polarized 3He Targets Using Thermally Polarized Water

When using the NMR technique of adiabatic fast passage (AFP) to monitor the polarization of ³He targets polarized using spin-exchange optical pumping at low magnetic fields, the absolute calibration of the polarimetry system can be achieved by comparison with the AFP signals of thermally polarized water. In this talk we will talk about an ultra-low noise custom-made NMR system capable of measuring an AFP signal from a thermally polarized water sample in a single measurement at 36 Gauss. We will also be talking about some of the systematics associated with signal averaging when using thermally polarized water for the calibration of AFP-based NMR systems at low fields. When comparing AFP signals from ³He and water, it is important to account for the dissimilarities in the shape of the glass containers holding the two samples. We will present a method of capturing the shape of the containers using spherical harmonics and a way of making corrections to the signal size based on that information.    

3D Printed Cryogenic Components for a Dynamic Nuclear Polarization Target

Recent advances in additive manufacturing allow for rapid development and prototyping of equipment. We have developed cryogenically stable components that survived multiple 1K temperature cycling using readily available 3D printing materials. We have also developed a method to print using flouroplastics, with a focus on Kel-F which is traditionally used in DNP targets due to their cryogenic properties, transparency to microwaves, and lack of free protons. These advances will be discussed, as well as recent exploration of 3D printing optical microwave components, 3D printing of scintillators, and 3D printing SRF cavities.    

A spectator reaction plane detector for the LHC

The ability to determine the reaction plane of a heavy ion collision using spectator neutrons is key to the study of directed flow and the chiral magnetic effect (CME) in these reactions.  A shower max detector, known here as the Spectator Reaction Plane Detector (SRPD) has been developed to map spectator neutron positions at zero degrees. In this specific design the SRPD is positioned between two elements of a Zero Degree Calorimeter (ZDC). The SRPD is comprised of a 4 x 4 array of 2 x 2 x 1 cm quartz elements.  GEANT simulations of detector performance will be compared to SPS Pb ion test beam results.  Predictions from GEANT for full energy LHC Pb beams will be presented.