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Title: GEANT SIMULATIONS OF PRESHOWER CALORIMETER FOR CLAS12 UPGRADE OF THE FORWARD ELECTROMAGNETIC CALORIMETER

Abstract

Hall B at the Thomas Jefferson National Accelerator Facility uses the CEBAF (Continuous Electron Beam Accelerator Facility) Large Acceptance Spectrometer (CLAS) to study the structure of the nucleon. An upgrade from a 6 GeV beam to a 12GeV beam is currently planned. With the beam energy upgrade, more high-energy pions will be created from the interaction of the beam and the target. Above 6GeV, the angle between the two-decay photons of high-energy pions becomes too small for the current electromagnetic calorimeter (EC) of CLAS to differentiate between two photon clusters and single photon events. Thus, a preshower calorimeter will be added in front of the EC to enable fi ner granularity and ensure better cluster separation for all CLAS experiments at higher energies. In order to optimize cost without compromising the calorimeter’s performance, three versions of the preshower, varying in number of scintillator and lead layers, were compared by their resolution and effi ciency. Using GSIM, a GEANT detector simulation program for CLAS, the passage of neutral pions and single photons through CLAS and the new preshower calorimeter (CLAS12 EC) was studied. The resolution of the CLAS12 EC was calculated from the Gaussian fi t of the sampling fraction, themore » energy CLAS12 EC detected over the Monte Carlo simulated energy. The single photon detection effi ciency was determined from the energy and position of the photon hits. The fractional energy resolution measured was ΔE/E = 0.0972 in the fi ve-module version, 0.111 in the four-module version, and 0.149 in the three-module version. Both the fi ve- and four-module versions had 99% single photon detection effi ciency above 0.5GeV while the 3 module version had 99% effi ciency above 1.5GeV. Based on these results, the suggested preshower confi guration is the four-module version containing twelve layers of scintillator and fi fteen layers of lead. This version provides a reasonable balance of resolution, effi ciency, and cost. Additional GSIM simulations will be undertaken to verify that the four-module version has acceptable π° mass reconstruction and to continue Research and Development (R&D) analysis on the preshower calorimeter.« less

Authors:
;
Publication Date:
Research Org.:
DOESC (USDOE Office of Science (SC) (United States))
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1052056
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Undergraduate Research; Journal Volume: 7
Country of Publication:
United States
Language:
English

Citation Formats

Whitlow, K., and Stepanyan, S. GEANT SIMULATIONS OF PRESHOWER CALORIMETER FOR CLAS12 UPGRADE OF THE FORWARD ELECTROMAGNETIC CALORIMETER. United States: N. p., 2007. Web.
Whitlow, K., & Stepanyan, S. GEANT SIMULATIONS OF PRESHOWER CALORIMETER FOR CLAS12 UPGRADE OF THE FORWARD ELECTROMAGNETIC CALORIMETER. United States.
Whitlow, K., and Stepanyan, S. Mon . "GEANT SIMULATIONS OF PRESHOWER CALORIMETER FOR CLAS12 UPGRADE OF THE FORWARD ELECTROMAGNETIC CALORIMETER". United States. doi:. https://www.osti.gov/servlets/purl/1052056.
@article{osti_1052056,
title = {GEANT SIMULATIONS OF PRESHOWER CALORIMETER FOR CLAS12 UPGRADE OF THE FORWARD ELECTROMAGNETIC CALORIMETER},
author = {Whitlow, K. and Stepanyan, S.},
abstractNote = {Hall B at the Thomas Jefferson National Accelerator Facility uses the CEBAF (Continuous Electron Beam Accelerator Facility) Large Acceptance Spectrometer (CLAS) to study the structure of the nucleon. An upgrade from a 6 GeV beam to a 12GeV beam is currently planned. With the beam energy upgrade, more high-energy pions will be created from the interaction of the beam and the target. Above 6GeV, the angle between the two-decay photons of high-energy pions becomes too small for the current electromagnetic calorimeter (EC) of CLAS to differentiate between two photon clusters and single photon events. Thus, a preshower calorimeter will be added in front of the EC to enable fi ner granularity and ensure better cluster separation for all CLAS experiments at higher energies. In order to optimize cost without compromising the calorimeter’s performance, three versions of the preshower, varying in number of scintillator and lead layers, were compared by their resolution and effi ciency. Using GSIM, a GEANT detector simulation program for CLAS, the passage of neutral pions and single photons through CLAS and the new preshower calorimeter (CLAS12 EC) was studied. The resolution of the CLAS12 EC was calculated from the Gaussian fi t of the sampling fraction, the energy CLAS12 EC detected over the Monte Carlo simulated energy. The single photon detection effi ciency was determined from the energy and position of the photon hits. The fractional energy resolution measured was ΔE/E = 0.0972 in the fi ve-module version, 0.111 in the four-module version, and 0.149 in the three-module version. Both the fi ve- and four-module versions had 99% single photon detection effi ciency above 0.5GeV while the 3 module version had 99% effi ciency above 1.5GeV. Based on these results, the suggested preshower confi guration is the four-module version containing twelve layers of scintillator and fi fteen layers of lead. This version provides a reasonable balance of resolution, effi ciency, and cost. Additional GSIM simulations will be undertaken to verify that the four-module version has acceptable π° mass reconstruction and to continue Research and Development (R&D) analysis on the preshower calorimeter.},
doi = {},
journal = {Journal of Undergraduate Research},
number = ,
volume = 7,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Within the upgraded D0 detector at Fermi National Accelerator Laboratory, forward and central preshower detectors will be used for fast level 1 triggering of electrons. These detectors consist of approximately 25000 channels of extruded scintillator strips with embedded wave length shifter fiber readout. Readout is via clear fiber lightguide to Visible Light Photon Counters. An overview of each system will be presented. Results of prototype detectors to cosmic rays will be presented. Scintillator/fiber manufacture and assembly will be discussed. {copyright} {ital 1998 American Institute of Physics.}
  • Within the upgraded D0 detector at Fermi National Accelerator Laboratory, forward and central preshower detectors will be used for fast level 1 triggering of electrons. These detectors consist of approximately 25000 channels of extruded scintillator strips with embedded wave length shifter fiber readout. Readout is via clear fiber lightguide to Visible Light Photon Counters. An overview of each system will be presented. Results of prototype detectors to cosmic rays will be presented. Scintillator/fiber manufacture and assembly will be discussed.
  • The torus magnet for the CLAS12 spectrometer is a 3.6 T superconducting magnet being designed and built as part of the Jefferson Lab 12 GeV Upgrade. The magnet consists of six coil case assemblies mounted to a cold central hub. The coil case assembly consists of an aluminum case and cover enclosing an epoxy vacuum impregnated coil pack. The coil pack consists of a 117 turn double-pancake winding wrapped with 2 layers of 0.635 mm thick copper cooling sheets. The coil case assembly is cooled by supercritical helium at 4.6 K. This report details the structural analysis of the coilmore » case assembly and the assessment of the coil pack stresses. For the normal operation of the torus magnet, the coil case assembly was analyzed for cool down to 4.6 K and the Lorentz forces at normal operating current. In addition to the normal operating configuration, the coil case assembly was analyzed for Lorentz forces arising from coil misalignment and current imbalances. The allowable stress criteria for the magnet followed the approach of the ASME codes. Primary stresses were limited to the lesser of 2/3 times the yield strength or 1/3 times the ultimate tensile strength. Primary plus secondary stresses were limited to 3 times the primary stress allowable. The analysis was performed using ANSYS Maxwell to calculate the magneto-static loads and ANSYS Mechanical to calculate the stresses.« less
  • The forward calorimeter upgrade to the PHENIX forward spectrometers aims to add capabilities at high rapidity (0.9<eta<3.0) in order to significantly extend the kinematic reach of PHENIX's DELTAG measurement for the prompt photon and photon-jet channels, study transverse spin physics through forward hadron asymmetries, study nucleon structure in nuclei at high parton densities in p+A collisions through the measurement of photons and neutral pions in the forward region, and enhance our quark and anti-quark spin measurements via W-production by providing an isolation cut and possibly providing an electron measurement at forward rapidities.
  • Over the past few years, the PHENIX detector has undergone several upgrades in the forward region (1<|{eta}|<4), initially covered only by the muon arms. The focus of these upgrades is toward a better understanding of the Color-Glass Condensate and the interplay between the different components of the proton's spin valence/sea quark and gluon contributions. This paper highlights the newly proposed forward calorimeter detector, FOCAL. FOCAL is a tungsten-silicon sampling calorimeter with high position and energy resolution, covering a pseudorapidity of 1.6<{eta}<2.5. This future detector aims to constrain the current view of gluon saturation at small x in the Color-Glass Condensatemore » framework, through isolation of direct photons at high-p{sub T} over a broad range of pseudorapidity.« less