Institute of Basic Science Rare Isotope Science Project PANGEA P hoton detector system for A stro-science and N uclear physics with GE rmanium A rray In-Il Jung Experimental System Division Low Energy Nuclear Science Team

PANGEA P hoton detector system for A stro-science and N uclear physics with GE rmanium A rray Compton suppressed Super Clover Detectors + Full Digital Signal Processor Multi-purpose gamma-ray spectrometer with high-efficiency and high-resolving power - Doppler broadening correction - Linear polarization measurement

Super Clover Detector 4 Fold Segmented : 4 x (8 segments + 1 full volume) Length : 90mm Diameter : 60mm Relative efficiency ≥ 38% Average relative efficiency ≥ 39% Measured Efficiency : 41~43% Sensitivity 200 mV/MeV (±10%) A D C B Cristals Anti- Compton Shield Pre- amplifiers Liuid Nitrogen Tank

Readout Electronics Tirgger, Parameter and Data Transfer Controller Double Trigger Control per Each Port 12 Input Ports and 1 Output Port VME 64 x BUS VME to USB Bridge for Data Transfer 6U Size B (160 mm x 233 mm) Digitizing Data from Clover Detectors Trapezoidal Digital Filter Floating Window Deconvolution Charge Extraction Gain Controllable 10-channel Digitizer Inputs (10 ADCs) 14 bits Resolution 100 Mega samples per second

Data Acquisition System TIG VME CONTROLLER TIG VME Crate CONTROLLER TIG-C USB 2.0 Off-line monitoring & Analysis HOST PC Memory DATA Storage HOST PC Memory DATA Storage Data User Current Status VME 64 BUS TIG-C VXI Crate TIG-10

Data Acquisition System TIG VME CONTROLLER TIG Optical Link Online monitoring & Analysis VME Crate CONTROLLER TIG-C HOST PC Memory DATA Storage HOST PC Memory DATA Storage Online Data User Future Plan TIG-C VXI Crate TIG-10 VME 64x BUS

Performance test of a super clover detector system Conditions Energy resolution check Source: 60 Co, 57 Co (Activity <10  Ci) Source-to-Detector distance: <10 cm (variable) Electronics check & Add-back mode Source: 60 Co (Activity <10  Ci) Source-to-Detector distance: 35 cm (fixed) Energy resolution check for all electrodes Energy resolution vs Peaking times of digital filter Efficiency enhancement due to an add-back mode

Energy resolutions of all electrodes Guaranted value for 1332-keV  Guaranted value for 122-keV  3.3 keV 2.6 keV Electrode NO.

Energy resolutions vs. peaking times  Signal Processing Block Diagram  The trapezoidal filter (low pass) 1) K = L – maximum charge collection time 2) Charge evaluator: a) Any point on the flat portion of the trapeze (or the maximum point) b) A gated integral of duration K of function F n (enclosed within the interval L) 3) If K = L, the trapeze becomes a triangle.

Comparing the efficiencies of between normal and add-back modes A B D C COUNT Energy EAEA ECEC EDED Normal Mode - Four Individual Detectors - E = E A, E C, E D Add-back mode - One detector consisting of four crystals - E = E A +E B +E C +E D COUNT Energy E Exp. Normal Add-back

Future works  Development of dedicated DAQ system for PANGEA  Electronics development for BGO Compton shield detectors  Dead time estimation for electronics  Performance estimation for various functions of super clover detector by GEANT simulation - Doppler broadening correction - Compton polarimeter - Background rejection method based on Compton imaging, etc.  Development of a gamma-ray tracking method - Improvement of 3D position uncertainty by using a pulse shape analysis method - Determination of interaction sequence by using stochastic or non-stochastic methods