1. Performance and applications of a  -TPC K. Miuchi a†, H. Kubo a, T. Nagayoshi a, Y. Okada a, R. Orito a, A. Takada a, A. Takeda a, T. Tanimori a, M. Ueno a, O. Bouianov b, M. Bouianov c a: Kyoto University b: Massachusetts Institute of Technology c:CSC-Scientific Computing Ltd. † Contact Address: Kentaro Miuchi miuchi@cr.scphys.kyoto-u.ac.jp Cosmic-Ray Group, Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto, 606-8502, Japan TEL +81(0)75-753-3867 / FAX +81(0)75-753-3799 1.Introduction 2.  -PIC 4.  -TPC (gas-filled operation) 5. Applications 6.Conclusions References [1] T.Nagayoshi, et al., Nucl. Instr. Meth. A 513(2003)277 [2] H.Kubo, et al. Nucl. Instr. Meth. A 513(2003)94 [3] K.Miuchi, et al., IEEE Trans. Nucl. Sci., 50(2003)825 [4] R.Orito, et al., Instr. Meth. A 513(2003)408, [5] T. Tanimori, et al., New Astronomy Rev. 48 (2004) 263 [6] K.Miuchi, et al., Nucl. Instr. Meth. A 517(2004)219 [7] T.Tanimori, et al., Phys. Lett. B 578 (2004) 241  -TPC : an “electric cloud chamber” REQUIREMENTS - Tracking minimum ionizing particles (MIPs) - Fine (sub-millimeter) samplings - Low ion-feedback  MeV gamma-ray camera [4,5] -  -TPC (recoil electron) + Scintillator (scattered gamma) - “electron track” gives event-by-event ray-tracing  Time-resolved neutron imaging[6] - n + 3 He → 3 H + p  -TPC : an “electric cloud chamber” DEVELOPMENT - 10×10×10 cm 3 detection volume - Fine tracking of proton, electron were shown. - First MIP tracks were detected. - Now we are entering the phase for “Applications”  Development [2,3] -  -PIC+ 8cm drift length - Digital-based electronics  PIC[1] “2-D imaging detector” -  m pitch, 120  m 2-D spatial resolution - Maximum gain 16000, operation gain 6000 (>1000hours) - PCB technology for large area (10×10 cm 2 in operation, 30×30cm 2 in development )  Ion feedback - Less than 30% for 10 4 cps/mm 2 X-ray (max 20keV)  Improvements - DAQ Clock rate 20MHz to 50MHz sampling ×2 - Amplifier time constant 16ns to 80ns S/N ×2 20mV 10mV  Dark matter experiment[7] - TPC is thought to be a very reliable method. - Low pressure operation: to be examined  MIP tracking - Ar-C 2 H 6 (80:20), 2atm - First “MIP tracks” were detected 3.  -TPC (gas-flow operation) hatched: Dark matter painted ： neutron BG Operation gain : >10000 MIP’s energy deposition: ~4 ion-e pairs/400  m (in Ar gas, 1atm) Schematics of  -PIC 10  m  -PIC on the boardX-ray image by  -PIC 10×10cm 2 Edge projection 2cm Feedback measurementFeedback fraction Feedback fraction = I D / I A 30×30 cm 2  -PIC in development MIP tracks MeV gamma-ray images  -TPC system Data acquisition Amplifier modificationClock rate up Electron tracks Conceptual design Prototype Neutron (Simulation) Expected dark matter “wind” Neutron signals Gas vessel 128ch cable  System - Gas vessel: 60cm, diameter 20cm height - 128ch feed-through cable (5cm width, 0.3mm thickness) - 10cm drift length (1mm copper wires) Feed-through Anger camera only “event circle” by conventional Compton cameras DM WIND γ F F AMP 50 MHz 20 MHz 16ns amplifier 80ns amplifier PEM TPC AMP PEM Whole system ~500 keV electrons Ar-C 2 H 6 (90:10) gain ~6000 ~1MeV protons Ar-C 2 H 6 (90:10) gain ~3000 Cosmic-ray muons Ar-C 2 H 6 (80:20) 2atm gain >10000 Thermal neutrons Ar-CF 4 - 3 He(78:20:2) 1.1 atm gain ~3000