Session E21: Instrumentation I

Live

Using the waveforms from a digital electronics system, an offline analysis technique on pulse shape discrimination (PSD) has been developed to improve the $n$-$\gamma$ separation in a bar-shaped NE-213 scintillator that couples to a photomultiplier tube (PMT) at each end. The new improved method, called the "valued-assigned PSD" (VPSD), quantifies the separation between neutrons and gamma rays. Position dependence of PSD can be taken into account and automated using VPSD method. The resulting $n$-$\gamma$ identification is much improved when compared to the traditional technique that uses the geometric mean (GM) of light outputs from both PMTs. This technique has been applied successfully to a recent experiment to better extract the neutron spectra for understanding the nuclear equation of state (EoS).   

Live

Microchannel plate photomultipliers have compact electron amplification design, providing them with excellent magnetic field immunity and precision timing performance. These characteristics make them promising potential photosensors for Nuclear Physics programs. We report the improvement of MCP-PMTs with low-cost microchannel plates functionalized by the atomic layer deposition technique at Argonne National Laboratory. Multiple photomultipliers were fabricated with different microchannel plate pore sizes and gap lengths. Their magnetic field immunity and precision timing performance were characterized and compared. With smaller pore size microchannel plates and reduced gap lengths, the magnetic field immunity of these photomultipliers improves from 0.7 Tesla to over 1.5 Tesla, the precision timing characteristics are also improved with a rise time from 519 ps to 394 ps, time resolution in a single photoelectron mode from 68 ps to 35 ps, and a root-mean-square timing distribution from 132 ps to 83 ps. To expedite the application of MCP-PMT for various programs, a $10 \times 10 cm^2$ MCP-PMT fabrication facility is under construction at Argonne to produce larger size, high-performance MCP-PMTs.   

Live

The Jefferson Lab Continuous Electron Beam Accelerator Facility’s experimental Hall A employs a Compton polarimeter to measure incoming beam polarization for parity violating electron scattering experiments. The polarimeter operates by amplifying green laser light in a Fabry-Perot cavity which then Compton scatters off the incoming electron beam. The scattered photons are then passed through a scintillating GSO (Gadolinium Oxyorthosilicate) crystal with a single photomultiplier tube. The polarization measurement is conducted by taking advantage of the helicity-dependence of compton scattering. By measuring the integrated signal from photons scattered while the beam is in different helicity states, we generate a differential asymmetry between these states, which then yields information about the electron beam’s longitudinal polarization. Measuring the asymmetry requires a robust background subtraction of helicity-correlated asymmetry as well as identifying the compton edge from observing spectra. The beam polarization is an important component needed to determine the parity-violating asymmetry for the CREX experiment. This talk will focus on the analysis of the integrating photon detector data.   

Live

Gammasphere continues to be heavily utilized for experimental investigations associated with both nuclear structure and nuclear astrophysics related research with a rich history of collecting data for nearly 30 years. Initially, the data acquisition (DAQ) system was based on custom made mixed analog/digital electronics packaged in a VXI system. Recently, a VME digital DAQ system was implemented based on digitizer and trigger hardware developed for GRETINA with new firmware designed at ANL specifically for use with detector systems at the ATLAS facility. The VXI capabilities were retained for detector control and monitoring, and thus most of the functionality is obsolete. In addition, Gammasphere’s 110 Ge detectors are 25-30 years old, and their preamps are a customized design that is no longer supported by the vendor. As such, diagnosis and repair of these preamps has been a necessary and workforce intensive task. This problem is compounded by the age of the components some of which have become obsolete. We have developed replacements for both the control system and the preamps to address these maintenance/repair issues, better mesh with the digital DAQ system and improve the control/monitoring infrastructure. Results from our work and final design plans will be presented.   

Live

\sout{\textsc{THE SPHENIX EXPERIMENT IS A NEXT-GENERATION EXPERIMENT DESIGNED TO STUDY THE QUARK GLUON PLASMA USING JETS AND QUARKONIA SPECTROSCOPY. THE MAPS-BASED VERTEX DETECTOR (MVTX) WITHIN SPHENIX IS USED FOR PARTICLE TRACKING AND VERTEXING, AS WELL AS PROVIDING CAPABILITIES FOR HEAVY-FLAVOR STUDIES. TESTING OF THE MVTX READOUT UNITS FOR THE SPHENIX DETECTOR IS ONGOING AT OAK RIDGE NATIONAL LABORATORY. THESE READOUT UNITS ARE HIGH GRANULARITY, LOW POWER, FAST, AND RADIATION TOLERANT, WITH THE CAPABILITY OF HANDLING THE HIGH EVENT RATE AND RESOLUTION REQUIREMENTS OF THE SPHENIX DETECTOR. TESTING CONSISTS OF CHECKING THE READOUT UNITS FOR ERRORS, SUCH AS SHORT CIRCUITS AND OPTICAL FIBER LOOPBACK ISSUES, CONFIRMING FUNCTIONALITY OF THE VARIOUS COMPONENTS, AS WELL AS PROGRAMMING THE BOARDS FOR USE WITHIN SPHENIX. AN OVERVIEW OF THE READOUT UNITS, TEST PROCEDURES, AND SOME PRELIMINARY RESULTS ARE PRESENTED.}}   

Live

The MUon Proton Scattering Experiment (MUSE) at the Paul Scherrer Institute will measure the muon-proton and electron-proton elastic cross sections in the same experiment.  The scattered-particle scintillators (SPS) are part of the event trigger and help with the particle separation and reaction identification via time-of-flight (TOF) measurements. These detectors are made out of organic plastic scintillators (EJ-204), which are up to 220-cm long, and are read out with Hamamatsu R13435 photomultiplier tubes. This presentation will discuss methods to determine the energy calibration, signal attenuation, and thresholds of the SPS detectors.   

Live

Though several measurements of the sodium quenching factor in thallium-doped sodium iodide (NaI(Tl)) detectors exist, results from current measurements are in disagreement below about 30 keV$_{nr}$. This discrepancy directly impacts the interpretation of results from NaI(Tl)-based WIMP direct detection and coherent neutrino-nucleus elastic scattering searches. It has been suggested that this disagreement, rather than reflecting a true variation of the quenching factor across different NaI(Tl) detectors, is due to unaccounted for systematic errors in previous measurements. In particular, it has been suggested that previous experiments have overestimated the quenching factor at low energies due to an imperfect knowledge of the trigger efficiency of the NaI(Tl) detector setups. To reconcile the tension between measurements, we have performed an experiment to measure this quenching factor in five separate NaI(Tl) detectors in the same experimental setup. Additionally, we have implemented a "threshold-free" triggering scheme to remove possible bias arising from trigger inefficiency of the NaI(Tl) detector. In this talk, we will present the results of our experiment and a comparison with previous NaI(Tl) quenching factor measurements.   

Live

The PRex-II and CRex experiments measure the model-independent RMS radius of the neutron skin thickness for $^{208}$Pb and $^{48}$Ca nuclei respectively using parity-violating asymmetry in elastic electron scattering. The neutron skin thickness is an important parameter that has a broad impact on modeling the neutron star structure, heavy iron collisions, and atomic parity violation experiments. PRex and CRex experiments were performed in Jefferson Lab Hall A with the High resolution Spectrometer(HRS) pair. In this report, I will discuss the Optics Calibration of the High Resolution Spectrometers, and the impact of the spectrometer optics on the neutron skin thickness results.   

Live

We present progress in the development of a neutron-detector array consisting of modules made from $\emph{p}$-terphenyl, a bright, fast, n/$\gamma$-discriminating solid organic scintillator. The module is comprised of 2x2x2cm$^3$ $\emph{p}$-terphenyl crystals that have been optically-coupled lengthwise to create a pseudo-bar module. While only relying on a photomultiplier tube on each end, the detector module is capable of distinguishing interactions between six or more crystals while maintaining the scintillator's pulse-shape discrimination (PSD) capability down to $\sim$150keVee. Here we present the PSD, position-discrimination, and timing-resolution characteristics of a single module. Additionally, the progress on array construction and the planned commissioning experiment will be briefly discussed.   

Live

To characterize the shielding efficiency of a Bi2O3-PMMA based compound (Cao et al,2020) we use a Monte Carlo method (GEANT4) approach. The spectral component of solar protons and secondary radiation were studied. We seek to estimate the does reduction of Bi2O3-PMMA. Emphasis has been made on the experimental results obtained from solid stat nuclear track detectors and aluminum shielding. Results with aluminum shielding were experimentally obtained at the ISS. They served to validate the results from the Bi2O3-PMMA shielding compound. The aim is to foresee the effects in biosystems and electronic equipment during long term space exploration from dose estimations. Both, HZE-particles, and neutrons, are known to be directly present in GCR or as secondary radiation from GCR or solar protons. Adverse affects from radiation can be safely reduced, if doses can be adequately estimated