S. Normand,1 V. Kondrasovs, 1 G. Corre, 1 J.-M. Bourbotte, 1 A. Ferragut 2 1 Laboratoire Capteurs et Architectures Electroniques 2 Saphymo september 2011, Helsinki, Finland Speaker: K. Boudergui Neutron-gamma Discrimination in Standard Plastic Scintillators : application for passive neutron measurements

2 Overview  Neutron-gamma discrimination goals  Is using a hardware a solution ?  How to manage discrimination by signal processing ?  Experimental results K. BOUDERGUI etal., - 28th september 2011

3 Plastic scintillators properties  A low cost detector  Neutron-gamma discrimination is complex (especially in solid detectors) Working on signal processing improvements rather than on intrinsic material properties Liquid Organic scintillator Boron loaded plastic scintillator plastic scintillator simpleHard low high COST He3 DISCRIMINATION ABILITIES Neutron gamma discrimination goals K. BOUDERGUI etal., - 28th september 2011

4  Plastic Scintillators constraints  Fine pulse shaping with a high data rate analog to digital conversion (800 MHz, 8bit ADCs). Signal width about 20 ns with a rise time around 2 ns.  Hardware and Software partition for best data processing  Ad-hoc neutron-gamma discrimination algorithm Neutron gamma discrimination goals K. BOUDERGUI etal., - 28th september 2011

5 Scintillator PA RT<=1ns G=10-50 ADC 200 MHz 8 bit ADC 200 MHz 8 bit ADC 200 MHz 8 bit ADC 200 MHz 8 bit Delay ns HT µC HV management Setting and monitoring Data and control transfers -HT FPGA PC End User Interface Data (4 Bytes, 200 MHz) Is using a hardware a solution ? K. BOUDERGUI etal., - 28th september 2011

6 4 ADCs 200 MHz, 8 bits 100 MHz PIC32 µc SPARTAN III FPGA demonstration- board Delay line Is using a hardware a solution ? CEA digitizing board K. BOUDERGUI etal., - 28th september 2011

7 How to manage discrimination by signal processing ?  Neutron-gamma discrimination patented algorithm  Signal splitted into two parts: One is delayed, the other, emphasized One without any change  Both signals are merged and then generate two quantities plotted in a bi- dimensional spectrum  Two regions appears, one for , one for  and some crosstalk K. BOUDERGUI etal., - 28th september 2011

8 Neutron Gamma Let’s have a better look on the signal ! Gamma After a pre-processing, two quantities are generated : sigma 1 and sigma 2 as described before (Positive and negative fraction) How to manage discrimination by signal processing ? Neutron (Only positive fraction) K. BOUDERGUI etal., - 28th september 2011

9 Source Total count rate Neutron count rate Am c/s130 c/s Cs c/s120 c/s Cf c/s320 c/s Co c/s128 c/s Background2200 c/s120 c/s Cf-252 Neutron and gamma Co-60 Gamma only Experimental results K. BOUDERGUI etal., - 28th september 2011

10 Experimental results K. BOUDERGUI etal., - 28th september 2011

11  No raising in the count rate is observed when we are set in a “neutron counting mode” and a gamma source is added ( 241 Am, 137 Cs, 60 Co)  The efficiency on neutron sensitivity is around 25% “estimated by the Monte Carlo MCNP simulation ( 252 Cf),”  A false alarm rate less than 0.01%  The detection probability is 97.5% for a 12,000 n/s neutron source at 1 meter (AIEA+ANSI) Experimental results K. BOUDERGUI etal., - 28th september 2011

12  Flexible and configurable hardware architecture allows to use it for a wide range of applications  Good performances obtained for homeland security applications with Plastic Scintillators  NR-module integration in an operating MA-NRBC system  Performance improvements will provide an He-3 alternative Summary K. BOUDERGUI etal., - 28th september 2011

Thank you for your attention K. BOUDERGUI etal., - 28th september 2011