Israel Mardor

Spectroscopy with CdZnTe γ- and X-ray detectors by modifying the electron trapping to compensate for incomplete charge collection caused by large hole trapping

Abstract We show a method for obtaining excellent spectroscopic performance for CdZnTe γ- and X-ray detectors with segmented readout. Best spectroscopic performance is obtained by tuning the electron trapping in the detector material to obtain optimum compensation for the incomplete charge collection caused by the large amount of hole trapping. For a CdZnTe detector with pad segmentation, we obtain for 57 Co a photopeak resolution of better than 3.5% FWHM with a peak-to-valley ratio of ∼100/1.

Performance of 1 cm /spl times/ 1 cm /spl times/ 1 cm pixelated CdZnTe gamma detectors

We present results for 1 cm /spl times/ 1 cm /spl times/ 1 cm coarsely pixelated CdZnTe gamma detectors. Large pixelated CdZnTe detectors are important for spectroscopic and imaging applications requiring sensitivity for higher gamma energies. For each gamma interaction, we process signals from all pixels and from the common electrode, and employ correction techniques developed at Soreq for improving the energy resolution and the photopeak efficiency. For illumination with an un-collimated /sup 133/Ba source, we obtain a combined pad spectrum with energy resolution of 4.8% FWHM for the 81 keV peak, and 1.6% FWHM for the 356 keV peak. We discuss the importance of detector material with high electron (/spl mu//spl tau/)/sub e/ for thick pixelated detectors. The experimental results are compared to theoretical simulations. This comparison aids in understanding of large pixelated detectors and provides a tool for designing new pixelated detector configurations.

The Soreq Applied Research Accelerator Facility (SARAF)

Even after a century of research, major aspects of nuclear physics still remain unknown, especially away from the valley of stability, or that require precise measurement of ultra-rare phenomena. Exploring this terra-incognita may shed new light on the genesis of elements in the universe, and may provide an excellent probe to physics beyond the Standard Model of elementary particles.

The EVA trigger: Transverse momentum selection in a solenoid

Abstract A custom CMOS LSI and ECL PAL-based trigger system for a particle physics experiment is presented. The EVA apparatus at Brookhaven National Laboratory is designed to observe large angle scattering near the kinematic limit of P T for hadron-proton scattering with cross sections in the picobarn range and interaction rates of 100 MHz. The trigger selects events with high P T tracks in a solenoidal straw tube tracking magnetic spectrometer in three stages. An ECL PAL scintillation hodoscope pretrigger and timing mask is followed by P T reconstruction from three superlayers of straw tube drift chambers using custom CMOS LSI integrated circuits. The higher level CMOS trigger system is implemented on custom modules and functions at secondary trigger rates in excess of 1 MHz. A Motorola MC68000 microprocessor resides on each module and uses global information on the event to provide a third trigger level. The modules are interfaced to VMEbus, controlled by a single board VME computer.

The Soreq Applied Research Accelerator Facility (SARAF) - Overview, Research Programs and Future Plans

Abstract.The Soreq Applied Research Accelerator Facility (SARAF) is under construction in the Soreq Nuclear Research Center at Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility for basic and applied nuclear physics, based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (SARAF-I, 4 MeV, 2 mA CW protons, 5 MeV 1 mA CW deuterons) is already in operation, generating scientific results in several fields of interest. The main ongoing program at SARAF-I is the production of 30 keV neutrons and measurement of Maxwellian Averaged Cross Sections (MACS), important for the astrophysical s-process. The world leading Maxwellian epithermal neutron yield at SARAF-I (

Scientific opportunities at SARAF with a liquid lithium jet target neutron source

5 \times 10^{10}

Spectroscopy for Compton interaction in pixelated CdZnTe detectors

5×1010 epithermal neutrons/s), generated by a novel Liquid-Lithium Target (LiLiT), enables improved precision of known MACSs, and new measurements of low-abundance and radioactive isotopes. Research plans for SARAF-II span several disciplines: precision studies of beyond-Standard-Model effects by trapping light exotic radioisotopes, such as 6He, 8Li and 18, 19, 23Ne, in unprecedented amounts (including meaningful studies already at SARAF-I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; nuclear structure of exotic isotopes; high energy neutron cross sections for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radiopharmaceuticals development and production. In this paper we present a technical overview of SARAF-I and II, including a description of the accelerator and its irradiation targets; a survey of existing research programs at SARAF-I; and the research potential at the completed facility (SARAF-II).

Research Programs And Plans At The Soreq Applied Research Accelerator Facility - SARAF

SARAF (Soreq Applied Research Accelerator Facility) is based on a 5 mA, 40 MeV, proton/deuteron accelerator. Phase-I, operational since 2010, provides proton and deuteron beams up to 4 and 5 MeV, respectively, for basic and applied research activities. The high power Liquid-Lithium jet Target (LiLiT), with 1.912 MeV proton beam, provides high flux quasi-Maxwellian neutrons at kT ~30 keV (about 2 × 1010 n/s/cm2/mA on the irradiated sample, about 1 cm from the target), enabling studies of s-process reactions relevant to nucleo-synthesis of the heavy elements in giant AGB stars. With higher energy proton beams and with deuterons, LiLiT can provide higher fluxes of high energy neutrons up to 20 MeV. The experimental program with SARAF phase-I will be enhanced shortly with a new target room complex which is under construction. Finally, SARAF phase-II, planned to start operation at ~2023, will enable full capabilities with proton/ deuteron beams at 5 mA and 40 MeV. Liquid lithium targets will then be used to produce neutron sources with intensities of 1015 n/s, which after thermalization will provide thermal neutron (25 meV) fluxes of about 1012 n/s/cm2 at the entrance to neutron beam lines to diffraction and radiography stations.SARAF (Soreq Applied Research Accelerator Facility) is based on a 5 mA, 40 MeV, proton/deuteron accelerator. Phase-I, operational since 2010, provides proton and deuteron beams up to 4 and 5 MeV, respectively, for basic and applied research activities. The high power Liquid-Lithium jet Target (LiLiT), with 1.912 MeV proton beam, provides high flux quasi-Maxwellian neutrons at kT ~30 keV (about 2 × 1010 n/s/cm2/mA on the irradiated sample, about 1 cm from the target), enabling studies of s-process reactions relevant to nucleo-synthesis of the heavy elements in giant AGB stars. With higher energy proton beams and with deuterons, LiLiT can provide higher fluxes of high energy neutrons up to 20 MeV. The experimental program with SARAF phase-I will be enhanced shortly with a new target room complex which is under construction. Finally, SARAF phase-II, planned to start operation at ~2023, will enable full capabilities with proton/ deuteron beams at 5 mA and 40 MeV. Liquid lithium targets will then be used to pr...

FIRST NUCLEAR-ASTROPHYSICS EXPERIMENTS WITH HIGH-INTENSITY NEUTRONS FROM THE LIQUID-LITHIUM TARGET LiLiT

Excellent spectroscopy for gamma rays can be obtained with pixelated CdZnTe detectors. Correction to the depth dependence of the pixel electrode signal can be made by simultaneously also measuring the common electrode signal. For high-energy gammas, thick detectors are required for increased detection efficiency. For increased efficiency, it is desirable to reconstruct Compton events, 2-pixel events that include the Compton scatter and re-interaction. The ambiguity in depth information for two pixel events in the same detector, with only one common signal, can be overcome taking advantage of sharp correlation with the relative difference of these two pixels. We present measurements made with a 1cm /spl times/ 1cm /spl times/ 1cm CdZnTe detector with the anode segmented to a 4 /spl times/ 4 array of pad electrodes. For each gamma interaction, signals for all the 16 pad electrodes and for the common cathode electrode were digitized to enable further correction for the depth of gamma interaction, and for the reconstruction of Compton scatter interactions. We focus on the 1.115 MeV line of /sup 65/ Zn source. For single pixel events, the summed corrected pad spectra yields an energy resolution of better than 1.0 % FWHM. Reconstruction of Compton events were made with signals from all combinations of 2 nearest neighbor pad electrodes, with corrections relying on the common electrode signal and also on the relative difference between the two pixel signals. A summed spectrum was for the Compton events was obtained with a energy resolution of 1.1 % FWHM for the 1.115 MeV line.

High p{sub t} quasi-exclusive scattering with resonance production

The Soreq Applied Research Accelerator Facility (SARAF) is under construction at the Soreq Nuclear Research Center, Yavne, Israel. When completed at the beginning of the next decade, SARAF will be a user facility based on a 40 MeV, 5 mA CW proton/deuteron superconducting linear accelerator. Phase I of SARAF (4 MeV, 2 mA CW protons, 5 MeV 1 mA pulsed deuterons) is already in operation. By use of a novel liquid lithium jet target (LiLiT), we generated up to 5×10^10 epithermal neutrons/sec, mainly for nuclear astrophysics research of slow neutron capture processes (s-process). We present a survey of research programs and plans at the completed SARAF, which span several disciplines: Precision studies of beyond-Standard-Model effects by trapping light exotic isotopes, such as 6He, 8Li and Ne isotopes, in unprecedented amounts (including meaningful studies already at Phase I); extended nuclear astrophysics research with higher energy neutrons, including generation and studies of exotic neutron-rich isotopes relevant to the rapid (r-) process; high energy neutrons cross section measurements for basic nuclear physics and material science research, including neutron induced radiation damage; neutron based imaging and therapy; and novel radio-pharmaceuticals development and production.