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Detector Upgrades and Responsibilities

BLAST@DORIS Workshop, DESY, March 31, 2008. Detector Upgrades and Responsibilities. Michael Kohl. Hampton University, Hampton, VA 23668, USA. Proposed Experiment. Electrons/positrons (100mA) in multi-GeV storage ring DORIS at DESY, Hamburg, Germany

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Detector Upgrades and Responsibilities

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  1. BLAST@DORIS Workshop, DESY, March 31, 2008 Detector Upgrades and Responsibilities Michael Kohl Hampton University, Hampton, VA 23668, USA

  2. Proposed Experiment • Electrons/positrons (100mA) in multi-GeV storage ringDORIS at DESY, Hamburg, Germany • Unpolarized internal hydrogen target (buffer system)3x1015 at/cm2 @ 100 mA → L = 2x1033 / (cm2s) • Large acceptance detector for e-p in coincidenceBLAST detector from MIT-Bates available • Redundant monitoring of luminositypressure, temperature, flow, current measurementssmall-angle elastic scattering at high epsilon / low Q2 • Measure ratio of positron-proton to electron-protonunpolarized elastic scattering to 1% stat.+sys.

  3. OLYMPUS pOsitron-proton and eLectron-proton elastic scattering to test the hYpothesis of Multi- Photon exchange Using DoriS OLYMPUS Hera ZEUS Hermes

  4. Control of Systematics BLAST @ DORIS Luminosity monitors 10o • Change BLAST polarity once a day • Change between electrons and positrons once a day • Left-right symmetry

  5. Control of Systematics i = e+ or e- j= pos/neg polarity Geometric proton efficiency: Ratio in single polarity j Geometric lepton efficiency:

  6. Control of Systematics Super ratio: Cycle of four states ij Repeat cycle many times • Change between electrons and positrons every other day • Change BLAST polarity every other day • Left-right symmetry

  7. Luminosity Monitoring • Measure Lij relative and continuously • Pressure, temperature, flow, current measurements • Forward-angle (high-epsilon, low-Q) elastic scattering (se+ = se-) • Moller scattering • … At forward angle:

  8. Forward Elastic Luminosity Monitor • Forward angle electron/positron telescope with good angular and vertex resolution • Coincidence with proton in BLAST • High rate capability • GEM technology? MIT protoype: Telescope of 3 Triple GEM prototypes (10 x 10 cm2) using TechEtch foils F. Simon et al., IEEE2007, arXiv:0711.3751

  9. Forward Elastic Luminosity Monitor • Two symmetric GEM telescopes at 10o • Sub-percent luminosity measurement per hour for all energies • 22.5 msr = 30 x 30 cm2 at 200 cm distance • Two GEM layers with ~0.1 mm resolution with ~10 cm gap→ Vertex resolution (z) of ~1cm at 10o • Two-photon effect negligible at high-e / low-Q2

  10. MIT GEM-Lab • GEM R&D at MIT Laboratory for Nuclear Science (LNS)and MIT-Bates Linear Accelerator • Upgrade of STAR forward tracker Richard Milner (Principal Investigator)Bernd Surrow (Assistant Professor since 2003)Douglas Hasell (Principal Research Scientist)Frank Simon (Postdoc, previously COMPASS)Jim Kelsey (MIT-Bates Mechanical Engineering)Miro Plesko (MIT-Bates Electronic Engineering) • F.S. now Junior Group Leader at MPI Munich

  11. HU Nuclear Physics Group Cynthia Keppel (Endowed Professor)Eric Christy (Associate Professor)Rolf Ent (Adjunct Professor)Antje Bruell (Adjunct Professor)M.K. (Assistant Professor) Howard Fenker (Jlab)

  12. Providing GEM technology • Collaboration HU-MIT • Goal: Establish HU/Jlab GEM R&D Center • Howard Fenker / Bonus collaboration • Thia Keppel / Medical physics applications • Proton Cancer Therapy Center under construction at HU • Augment 12 GeV program at Jlab • By building C0 cylindrical GEM tracker for TREK, provide technology for 12 GeV program at Jlab • Luminosity monitors for OLYMPUS • Contributions to OLYMPUS further program?

  13. Principle of GEM Detectors • GEM = Gas Electron Multiplierintroduced by F. Sauli in mid 90’s, F. Sauli et al., NIMA 386 (1997) 531 • Copper layer-sandwiched kapton foil with chemically etched micro-hole pattern gas amplification in the hole

  14. 70 µm 140 µm 5 µm 70 µm 55 µm 50 µm`` GEM foils Typically 5mm Cu on 50mm kapton ~104 holes/cm2 • Chemical etching • R. De Oliveira (CERN-EST) • TechEtch (MIT, BoNuS) • 3M Corporation • Laser drilling • Tamagawa (RIKEN)

  15. Multi-GEM Detectors • GEMs can be cascaded for higher gain • Gain of 104 needed for efficient MIP detection Double GEM Triple GEM C. Buettner et al., Nucl. Instr. and Meth. A 409(1998)79 S. Bachmann et al., Nucl. Instr. and Meth. A 443(1999)464

  16. TREK/E06 Tracking Upgrade 70 µm 140 µm Time Reversal Experimentwith Kaons: Search for PT (Km3) GEM technology • 12 Planar GEMs (C1) between CsI and C2 • 1 Cylindrical GEM (C0) in replacement of former C1

  17. C0 Cylindrical GEM for TREK 300 mm 160 mm 140 mm

  18. BoNuS • Radial TPC (8-12 cm in./out. Diameter, 20cm active length) • Ran in CLAS end of 2005, first experiment to use cylindrical GEM detector • Further development planned for CLAS and Jlab-12 GeV→ Howard Fenker • H. Fenker et al., submitted to NIM (2008)

  19. BoNuS Barely off-shell Nuclear Structure • Tag neutron initial momentumby measuring spectator proton at low momentum-> neutron structure • Tag energetic pions by tracking low-momentum a’s and tritons in pion production-> pion cloud study

  20. OLYMPUS Detector / Upgrades • Crucial components for OLYMPUSBLAST core detector (WC+CC+SC)Additional e+,e- discrimination?Luminosity monitoring

  21. Further use of BLAST @ DORIS • Polarized H/D target (ABS) • Neutron detectors • Recoil detectors • Inner tracker • Forward-angle tracking • Forward tagging system/quasireal photons

  22. OLYMPUS Responsibilities • DORIS - DESY • Transfer of BLAST detector – MIT/Bates • BLAST Cerenkov counters – ASU • BLAST Time-of-flight scintillators – UNH • Unpolarized gas target – MIT/Bates • Luminosity monitors – HU/Jlab • Electron/positron ID • Maintenance and operation of detector components • Simulation tasks • Analysis tasks

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