Search

An experiment to search for 2ε-, εβ+- and 2β+-decays of 106Cd, using a 215 g cadmium tungstate scintillation crystal enriched at 66 % by 106Cd (106CdWO4) is carried out at the Gran Sasso underground laboratory (Italy). Events in the 106CdWO4 detector are recorded in (anti)coincidences with two large-volume CdWO4 scintillation counters. The design of the detector system, calibration and background measurements, methods, and results of data analysis to determine key detector characteristics are described. The experimental data are compared with Monte Carlo simulation results, and a background model is constructed. The radioactive contamination of the setup components is studied. The sensitivity of the experiment approaches the level of theoretical predictions for the 2νεβ+-decay channel, while for other possible 2β-decay channels it is already on the level of lim T1/2 ∼ 1021-1022 years.

In this work, the gamma-ray shielding parameters of red clay and boron-doped red clay with different sample thicknesses are theoretically and experimentally reported. These shielding parameters are considered at a photon energy of 0.662 MeV emitted from 137Cs. The theoretical calculations are demonstrated using the XCom software program, while a scintillation detector, NaI(TI), with an efficiency of 98% is used to attain the experimental results of the mass attenuation coefficient of the prepared samples. The acquired results show that the boron-doped clay delivers a higher mass attenuation coefficient as compared to those of pure clay. Additionally, the mass attenuation coefficient exhibits an increasing behavior with the sample thickness increment. [ABSTRACT FROM AUTHOR]

Readout electronics for the scintillation bar tracking detector (SciBar) in the K2K neutrino oscillation experiment has been developed. SciBar has 14336 scintillator bars in total. The deposited energy and timing of particles from neutrino interactions in the scintillator bars are measured by 64-channel multianode photo-multiplier tubes (MAPMTs). Compact custom-designed electronics to record the MAPMT signals were developed, consisting of front-end circuit boards attached to each MAPMT and back-end electronics modules sitting in a VME crate. The front-end circuit board multiplexes pulse-height information from all 64 anodes and generates a fast triggering signal. Two sets of ASICs (IDEAS VA32HDR11 and TA32CG) are employed for these functions. The bias voltages and relay of control signals are also handled on the board. The back-end electronics module controls the front-end board by providing the control, timing, and low-voltage signals. The board also digitizes the multiplexed signal from the front-end. The electronics achieves low noise of less than 0.3 photoelectrons and and linearity up to 300 (150) photo-electrons for MAPMTs at the gain of 5 × 105 (106). [ABSTRACT FROM AUTHOR]

A 256ch flat panel position sensitive photomultiplier tube (FP-PMT) is a promising device for a PET detector because of its large opening area, 52 mm × 52 mm, and small dead space. The useful area of the 256ch FP-PMT is 89% to the opening area. The 256ch FP-PMT contains 16 × 16 matrix anodes with 3.04mm intervals between them so that the 256ch FP-PMT affords optical coupling with a 16 × 16 array of scintillation crystals having 3 mm pact volume and less weight for the PET apparatus. Using a prototype 256ch FP-PMT, we measured light spread function of a central anode and crystal identification ability with 2.9 mm × 2.9 mm × 7.5 mm Gd2SiO5 (GSO) crystals. The full width at half maximum of the light spread function was found to be 4.6 mm. As regards positioning performance, the resultant positioning image map assures its capability for crystal identification in a 16 × 16 array of the GSO crystals. For the use of a 256ch FP-PMT having a large useful area, we made a new proposal for easier construction of an array with many crystal elements. The way utilizing multilayer polymer mirrors, a reflector, properly processed by laser can be applied to other various shaped detectors. [ABSTRACT FROM AUTHOR]

This work presents the results of investigations aimed at simulating the response of a barium fluoride (BaF2) detector to neutrons and photons. The simulations are performed with the MCNP-PoliMi code, a modification of MCNF-4C. The simulation results are compared to time-of-flight measurements performed with the nuclear materials identification system (NMIS). In particular, the neutron detection capabilities of the BaF2 scintillator are analyzed. [ABSTRACT FROM AUTHOR]