Neutron Imaging Detector based on the PIC Joe Parker Cosmic Ray - PowerPoint PPT Presentation

JPS Fall Meeting, Toyama University, 22 Sep 2011 Neutron Imaging Detector based on the µPIC Joe Parker Cosmic Ray Group, Kyoto University

JPS Fall Meeting, Toyama University, 22 Sep 2011 KYOTO UNIVERSITY, COSMIC RAY GROUP J.D. Parker, K. Hattori, S. Iwaki, S. Kabuki, Y. Kishimoto, H. Kubo, S. Kurosawa, K. Miuchi, H. Nishimura, T. Sawano, T. Tanimori, K. Ueno JAPAN ATOMIC ENERGY AGENCY, MATERIALS AND LIFE SCIENCE FACILITY DIVISION M. Harada, T. Oku, T. Shinohara, J. Suzuki Neutron Imaging Detector based on the µPIC Prototype system and basic operation. Demonstration measurements. Future improvements.

Neutron imaging detector prototype (µNID) ALUMINUM VESSEL (pressures up to 2 atm) DRIFT CAGE 400 µm 9.0 cm µPIC 10 cm 10-cm µPIC 3 2 mfr. by DNP . 8 c n ABSORBER: m 3 He GAS ALUMINUM DRIFT High-rate FPGA-based DAQ. PLANE (0.3 mm) TPC measures 3D proton-triton tracks. Energy deposition estimated by time- above-threshold method. 2.5 cm Gas gain < 1000 for neutron imaging. Efficiency up to ~30%, position res. of Prototype with ~120 µm, time res. of ~1 µs. top removed.

DAQ and FPGA logic (ATLAS, KEK) Amplifier-Shaper-Discriminators PROTON-TRITON TRACKS FPGA Position Entries Entries 28 28 VME 50 Relative clock pulse encoder 45 µPIC memory 33-bit LVDS 40 35 ( � 2) 30 VME bus 25 32 bits: 20 15 orientation, 10 time, 5 External 0 0 10 20 30 40 50 60 position, gate X (strips) PC Energy Deposition Digital out edge 30 Time-above-threshold (clocks) (256 ch � 2) 25 20 15 DATA ENCODING 10 µPIC µPIC 5 Threshold Threshold Two words per 0 0 10 20 30 40 50 60 X (strips) pulse. Simultaneous measurement ‘edge bit’ saved of position and ‘energy ASD ASD 0 1 with each data deposit’ at high rates. word. Excellent background Time-above-threshold rejection capability. ( ∝ energy deposit)

DAQ and FPGA logic (ATLAS, KEK) Amplifier-Shaper-Discriminators PROTON-TRITON TRACKS FPGA Position Entries Entries 29 29 VME 50 Relative clock pulse encoder 45 µPIC memory 33-bit LVDS 40 35 ( � 2) 30 VME bus 25 32 bits: 20 15 orientation, 10 time, 5 External 0 0 10 20 30 40 50 60 position, gate Y (strips) PC Energy deposition Digital out edge 30 Time-above-threshold (clocks) (256 ch � 2) 25 20 15 DATA ENCODING 10 µPIC µPIC 5 Threshold Threshold Two words per 0 0 10 20 30 40 50 60 Y (strips) pulse. Simultaneous measurement ‘edge bit’ saved of position and ‘energy ASD ASD 0 1 with each data deposit’ at high rates. word. Excellent background Time-above-threshold rejection capability. ( ∝ energy deposit)

DAQ and FPGA logic (ATLAS, KEK) Amplifier-Shaper-Discriminators PROTON-TRITON TRACKS FPGA Position Entries Entries 25 25 VME 50 Relative clock pulse encoder 45 µPIC memory 33-bit LVDS 40 35 ( � 2) 30 VME bus 25 32 bits: 20 15 orientation, 10 time, 5 External 0 0 10 20 30 40 50 60 position, gate X (strips) PC Energy Deposition Digital out edge 30 Time-above-threshold (clocks) (256 ch � 2) 25 20 15 DATA ENCODING 10 µPIC µPIC 5 Threshold Threshold Two words per 0 0 10 20 30 40 50 60 X (strips) pulse. Simultaneous measurement ‘edge bit’ saved of position and ‘energy ASD ASD 0 1 with each data deposit’ at high rates. word. Excellent background Time-above-threshold rejection capability. ( ∝ energy deposit)

DAQ and FPGA logic (ATLAS, KEK) Amplifier-Shaper-Discriminators PROTON-TRITON TRACKS FPGA Position Entries Entries 25 25 VME 50 Relative clock pulse encoder 45 µPIC memory 33-bit LVDS 40 35 ( � 2) 30 VME bus 25 32 bits: 20 15 orientation, 10 time, 5 External 0 0 10 20 30 40 50 60 position, gate X (strips) PC Energy Deposition Digital out edge 30 Time-above-threshold (clocks) NEUTRON (256 ch � 2) 25 20 PROTON 15 DATA ENCODING TRITON 10 µPIC µPIC 5 Threshold Threshold Two words per 0 0 10 20 30 40 50 60 X (strips) pulse. Simultaneous measurement ‘edge bit’ saved of position and ‘energy ASD ASD 0 1 with each data deposit’ at high rates. word. Excellent background Time-above-threshold rejection capability. ( ∝ energy deposit)

Test experiments at J-PARC Tokai, Ibaraki Experiments in Nov. 2009, June 2010, J-PARC and Feb. 2011. Beam power ~120 kW. Carried out at NOBORU beam line. Fill gas: Ar-C 2 H 6 - 3 He (63:7:30) at 2 atm, efficiencies ~28%(5 cm), ~13%(2.5 cm). Materials and Life Science Facility (MLF) NOBORU (BL10) De Detect ector or Bandwidth chopper position position Rotary collimator NOBORU BEAM LINE Moderator-to-detector distance of ~14.5 m. Max. beam size: 10 × 10 cm 2 . 25 Hz pulse rate, 10 Å band- width. Adjustable B 4 C slits

Long term operability AMPLIFIER-SHAPER- DISCRIMINATORS and 3 He usage (ASD) Same gas filling used for first two µNID experiments (separated by 8 months). No degradation in performance seen in June experiment. Gain recovered by increasing anode voltage. Prototype in SAMPLE Detector remained operable after more experimental area HOLDER than 1 year on single gas filling. at NOBORU. Strategies to extend operation Time after Gain filling (% of initial) Annealing of vessel and µPIC against outgassing. 1 st Exp (2009) 0 months 100 Careful selection of materials. 2 nd Exp (2010) 8 months 67 Gas purification or 3 He Dec 2010 13 months 30 reclamation system.

DAQ performance at NOBORU Time-averaged data rates from 200 kHz EXTERNAL TOF GATE ~ 9.4 MHz (neutron rate of 80~100 kHz). off on Large dead time (40 ~ 85%). Neutron Counts Encoder limits DAQ rate. 3 10 pulses VME-to-PC transfer creates dead time. 2 10 Limitations can be reduced with further hardware development. 10 0 10 20 30 40 50 60 70 80 90 100 EXTERNAL TOF GATE Time (ms) 40 ms Ex: Bragg transmission measurement (2010). Reduction in incoming data Ungated TOF > 3 ms means fewer VME readouts. 8948 191389 No. of pulses Effectiveness depends on details of TOF distribution and 34.5 226.2 Total time (min) gate. 82.7 43.6 Dead time (%) Useful for Bragg transmission, ~70% decrease in resonance absorption. measurement time.

Neutron-gamma separation Escape Fully-contained Event pile-up, Gamma rejection studied events neutrons scattered protons using RI sources. Time-above-threshold vs. Track length Time-above-threshold (clocks) 500 Data taken over 24 hours. 3 10 400 Pulse-width sum after track-length cut 300 2 10 Counts/hr/3.75 clocks Background 137 Cs 7 200 neutrons No source n 6 10 γ ’s from 100 5 γ 137 Cs 4 0 1 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 Length (cm) 3 ‘Energy’ cut 2 Both neutrons and gammas are 1 detected ( γ efficiency ~10 -3 ). 0 0 100 200 300 400 500 Avg. time (clocks) Neutrons selected by cuts in total time- above-threshold and 3D track length. Contamination fraction (95% CL) Fraction of detected γ ’s surviving < 5.5 × 10 -6 Track length neutron cuts < 10 -6 (effective gamma sensitivity of < 10 -9 ). < 2.9 × 10 -6 + PID

Position resolution with PID Cd TEST CHART 2 mm slits Position from mid- point of track. Resolution: ~1 mm ( σ ) No PID With PID 5 cm Resolution with PID: Proton direction from 349 ± 36 µm ( σ ) shape of distribution Energy deposition 30 Time-above-threshold (clocks) 25 (Includes beam 20 dispersion.) 15 10 5 0 Preliminary 0 10 20 30 40 50 60 Y (strips) Corrected Mid-point position Data taken at NOBORU, J-PARC in Nov. 2009.

Refining position Track length Pulse width from peaks Energy deposition resolution 30 Time-above-threshold (clocks) Track length from 25 extrapolation 20 Two methods: End-Point Extrapolation 15 10 (EPE) and Peak Interpolation (PI). 5 Combining both methods produces best 0 0 10 20 30 40 50 60 Y (strips) result of σ = 118.4 ± 0.2 µm. NO REFINEMENT EPE ONLY EPE + PI ( σ = 315 µm) ( σ = 182 µm) ( σ = 118 µm) 0.5 mm slits Preliminary 5 cm Data taken at NOBORU, J-PARC in Feb. 2011.

Image of a wristwatch µPIC (29 MIN.) IMAGING PLATE (200 MIN.) ~3.5 cm Resolution 50~60 µm. Preliminary Courtesy of Ohi, J-PARC. Bin size: 200 µm × 200 µm. Bin size can be decreased with higher statistics. Image processing techniques could improve image. Data taken at NOBORU, J-PARC in Feb. 2011 (µPIC).

JPS Fall Meeting, Toyama University, 22 Sep 2011 Demonstration measurements Resonance absorption. Bragg-edge transmission.

Resonance absorption Transmission Mn Sheets of In, Ta, Ag, Mo, and Mn. 1 Mo Ag 0.8 Typical area of 10 cm × 10 cm. Ta In 0.6 Thicknesses from 10 µm to 1 mm. 1 0.4 0.8 0.2 0.6 Preliminary Resonance absorption occurs 0 0.04 0.08 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 when neutrons of a particular Time (ms) energy are absorbed preferentially Transmission 1 by a target nucleus. 0.8 Large samples to accumulate Indium statistics quickly (~16 min/sample). 0.6 compared with Good time resolution and 0.4 ENDF/B-VII.0 background rejection allows us to 0.2 Preliminary see resonances near beginning of pulse. 0 0.5 0.6 0.7 0.8 0.9 1 Time (ms) Data taken at NOBORU, J-PARC in Feb. 2011.