Bulletin of the American Physical Society
APS April Meeting 2017
Volume 62, Number 1
Saturday–Tuesday, January 28–31, 2017; Washington, DC
Session E12: Instrumentation for Hadron Structure Studies |
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Sponsoring Units: DNP GHP Chair: Tanja Horn, Catholic University of America Room: Roosevelt 4 |
Saturday, January 28, 2017 3:30PM - 3:42PM |
E12.00001: The CLAS12-RICH hybrid geometry Giovanni Angelini A Ring-imaging Cherenkov detector (RICH) has been designed for the CLAS12 spectrometer (JLAB, Hall B) in order to increase the particle identification. Among the approved physics program focused upon 3D imaging of the nucleon, some Semi Inclusive Deep Inelastic Scattering experiments (E12-09-007, E12-09-008, E12-09-009) demand an efficient kaon identification across the momentum range from 3 to 8 GeV/c. The detector exploits a novel elaborated hybrid geometry based on a complex focusing mirror system that will reduce the area instrumented with photon detectors. For forward scattered particles ($\theta<12^\circ$) with momenta p = 3-8 GeV/c, a proximity imaging method with direct Cherenkov light detection will be used. For larger angles of $12^ \circ<\theta<35^\circ$ and momenta of p = 3-6 GeV/c, the Cherenkov light will be focused by a spherical mirror, undergo two further passes through the aerogel radiator and will be reflected from planar mirrors before detection. A carefully study on reflections has been performed considering microscopic and macroscopic effects. In addition, a new feature has been introduced in the CLAS12 simulation software in order to generate the geometry of the detector by using a computer-aided design (CAD) file for an accurate geometrical description. [Preview Abstract] |
Saturday, January 28, 2017 3:42PM - 3:54PM |
E12.00002: Nucleon transverse spatial and momentum structure with the Neutral Particle Spectrometer at Jefferson Lab Hall C Andres Vargas, Tanja Horn A representation of the proton's true inner structure requires one to describe orbital angular momentum, and important aspect for nucleon spin, for which one needs to describe the correlation between the momentum and spatial coordinates. A three-dimensional description of the nucleon has been developed through the Generalized Parton Distributions (GPDs) and the Transverse Momentum-Dependent parton distributions (TMDs). The tomography of the nucleon is one of the flagship science programs at the Jefferson Lab and the characterization of the anticipated GPD and TMD behavior as enabled by the Neutral Particle Spectrometer in Hall C is an important aspect. The NPS will allow accurate access to measurements of the hard exclusive and semi-inclusive scattering processes. The default readout of the NPS PbWO4-based calorimeter will be with conventional photomultipliers. However, reading out with SiPMs or other sensors with tolerance to radiation and magnetic fields may have advantages. In this talk we will review the experiment requirements and discuss an alternative readout system with silicon-based sensors. [Preview Abstract] |
Saturday, January 28, 2017 3:54PM - 4:06PM |
E12.00003: The Coordinate Detector for SuperBigBite Peter Monaghan, Vitaly Batourine, Mark Jones, Mahbub Khandaker, Lubomir Pentchev, Adam Sarty, Albert Shahinyan, Concetta Sutera, Francesco Tortorici, Bogdan Wojtsekhowski The Coordinate Detector (CDet) is a 2352-channel two-layer scintillator hodoscope, being constructed for use with the SuperBigbite Spectrometer (SBS) in the nucleon form factor experiments at the Thomas Jefferson National Accelerator Facility (JLab). Each layer of the detector consists of thin, scintillator paddles, each with a wavelength-shifting optical fiber through the middle, which is read out via a multi-anode photomultiplier tube. The CDet will provide charged particle coordinate resolution of 2 mm, which is important for elastic event identification at the projected very large luminosity of 10$^{39}$ Hz/cm${^2}$. An overview of the detector parameters and the current progress in construction, testing and commissioning is presented. [Preview Abstract] |
Saturday, January 28, 2017 4:06PM - 4:18PM |
E12.00004: Exclusive reactions and the PbWO4-based Inner Calorimeter for the Electron-Ion Collider Richard Trotta, Tanja Horn, Andres Vargas, Marco Carmignotto, Salina Ali, Rishabh Uniyal One of the main goals of the Electron-Ion Collider (EIC) is the three-dimensional imaging of nucleon and nuclei and unveiling the role of orbital angular motion of sea quarks and gluons in forming the nucleon spin. These studies are made possible through a new framework developed to explore nucleon structure through the Generalized Parton Distributions (GPDs) and the Transverse Momentum-Dependent parton distributions (TMDs). To carry out the scientific program, a specialized detector is needed. The particle identification requirements are driven by semi-inclusive and exclusive scattering processes like DVCS. For the latter an elimination or reduction of background events is mandatory. This requires good resolution in angle to distinguish between clusters, good energy resolution for measurements of the cluster energy, and the ability to withstand radiation. The small Moliere radius of the PbWO4 crystals makes them an ideal solution for the EIC inner crystal calorimeter. In this talk we will discuss what needs to be done to build a PbWO4-based inner calorimeter, the importance of PbWO4 quality, and results from ongoing crystal characterization efforts. [Preview Abstract] |
Saturday, January 28, 2017 4:18PM - 4:30PM |
E12.00005: Calibration of the HyCal calorimeter for the PRad Experiment at JLab Li Ye The “Proton Charge Radius Puzzle” refers to the large discrepancy observed between the proton charge radius extracted from muonic hydrogen Lamb shift measurements and that from the atomic hydrogen Lamb shift and e-p elastic scattering measurements. In order to get a better understanding of this puzzle, the PRad experiment (E12-11-106\footnote{Spokespersons: A. Gasparian (contact), H. Gao, M. Khandaker, D. Dutta}) was recently performed with 1.1 and 2.2 GeV unpolarized electron beam in Hall B at Jefferson Lab. The experiment aims to extract the electric form factor and the charge radius of proton by simultaneously measuring the $e-p$ elastic scattering cross section and the M$\o$ller cross section at very low $\rm{Q}^2 (2\times10^{-4} \sim 10^{-1} \rm{(GeV/c)}^2$) region, with sub-percent precision. A windowless hydrogen gas flow target was used to better control the background. A high-efficiency and high-resolution calorimeter (HyCal) and a pair of Gas Electron Multiplier (GEM) chambers were used in the experiment. Before the production run, a very careful calibration of HyCal was performed with 0.3 GeV - 1.07 GeV tagged photon beam. This talk will present detailed calibration results as well as some preliminary results on ep and ee scattering data. [Preview Abstract] |
Saturday, January 28, 2017 4:30PM - 4:42PM |
E12.00006: Confirming the potential for nucleon structure studies with neutral final states and the Neutral Particle Spectrometer at JLab Hall C Rishabh Uniyal, Tanja Horn The two-arm combination of neutral-particle detection and a high-resolution magnetic spectrometer offers unique scientific capabilities to push the energy scale for studies of the transverse spatial and momentum structure of the nucleon through reactions with neutral particles requiring precision and high luminosity. As example, it enables precision measurements of the deeply-virtual Compton scattering cross section and the basic semi-inclusive neutral-pion cross section, which is crucial to validate a cornerstone of 3D transverse momentum imaging. This science program is enabled by a Neutral-Particle Spectrometer (NPS) and the magnetic spectrometer pair in Hall C at the 12 GeV JLab. In this talk we will discuss the experiment the NPS will be used for and its components, for instance, the crystal array and what properties are desirable from the crystals to meet the specifications of the experiments. [Preview Abstract] |
Saturday, January 28, 2017 4:42PM - 4:54PM |
E12.00007: ABSTRACT WITHDRAWN |
Saturday, January 28, 2017 4:54PM - 5:06PM |
E12.00008: Low momentum recoil detectors in CLAS12 at Jefferson Lab Gabriel Charles Part of the experimental program in Hall B of the Jefferson Lab is dedicated to studying nucleon structure using DIS on nuclei and detecting low-momentum recoil particles in coincidence with the scattered electron. For this purpose, specially designed central detectors are required in place of the inner tracker of CLAS12 to detect particles with momenta below 100 MeV/c. We will present the status of the BONuS12 RTPC detector that will take data within the next 2 years. We will detail the main improvements made from the previous BONuS RTPC. In a second part, we will discuss another recoil experiment, called ALERT, that has been proposed to run in Hall B. The constraints being different, the recoil detector is based on a drift chamber and an array of scintillators. We will present the main differences between the two detectors and summarize the R&D performed to develop the ALERT detector. [Preview Abstract] |
Saturday, January 28, 2017 5:06PM - 5:18PM |
E12.00009: GEM Detectors of Proton Charge Radius (PRad) Experiment Xinzhan Bai The PRad experiment (E12-11-106\footnote{Spokespersons: A.Gasparan(Contact), H. Gao, M. Khandaker, D. Dutta}) was recently performed at Jefferson Lab in Hall B. It was designed to measure the proton charge radius with high precision, through the elastic electron proton scattering process, using a non-magnetic-spectrometer method. PRad experiment reached very small ep scattering angles and thus it can see an unprecedented small four-momentum transfer squared region, $Q^2$ from $2\times10^{-4}$ to $0.1 (\rm GeV/c)^2$. This experiment measures the proton charge radius by extracting the electric form factor of proton with a sub-percent precision. A pair of world's largest GEM detectors, and a high resolution calorimeter(HyCal) were utilized in the experiment. In this talk, we will present the performance of GEM detectors achieved in the experiment, such as efficiency and other characteristics, and preliminary analysis results of the experimental data. [Preview Abstract] |
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