Hybrid boron-10 gaseous detector for slow and fast neutron simultaneous detection

A hybrid position-sensitive neutron detector with active 10B-layer and proportional chamber filled by the gas mixture Ar+25%CO2 is being studied. The detector is used on the neutron source based at the linear accelerator. Recording two pairs of pulse heights which are produced in two gas gaps by 7Li and 4He nuclei between the anode and two cathodes gives a possibility to determine the X and Y neutron coordinates. This detector permits time-of-flight measurements. A significant difference in pulse height spectra for slow and fast (several MeV) neutrons was observed in experiment. In recent experiments with 10B-detector we found that (1) the pulse heights depend on the neutron energy and (2) the position of the maximum in the pulse height spectrum varies monotonically versus the maximum neutron energy.

Optical Readout Characteristics in a New Gas Scintillation Chamber for Neutron Measurement

A novel neutron diagnostic method is presented based on optical readout from scintillation in gases excited by recoil charged particles for fusion research. According to the method, we have designed a new gas scintillation chamber filled with scintillation gas CF4 and installed with a multi-wires structure to provide strong electric field. The electric field distributions of cylindrical multi-wire structures with different geometrical parameters are analyzed systematically. By building up an optimal multi-wire structure, the optical readout characteristics are also studied with energetic charged particles. Electron-induced avalanche in the electric field excites gas molecules to emit numerous scintillation photons, which are readout using photomultiplier tubes, and measured using multichannel analysers. The results show that the light signals and charge signals are enhanced simultaneously and the rise time of the light signal hardly changes, approximately 12ns, as the applied voltage increases. More importantly, the typical pulse height spectrum from the light signals is acquired, and the obtained resolution is 8.8% for 6.5MeV protons.

Recent Progress of Transparent Ceramic Scintillators

Recent progress of transparent ceramic scintillators is reviewed. The present work reports the research and development of oxide transparent ceramic materials such as garnet, sesquioxide, complex perovskite and some other kinds. Some representative scintillation properties such as scintillation emission spectra and decay times under X-ray irradiation are presented. Gamma-ray induced scintillation detector properties including pulse height spectrum, energy resolution, and light yield nonproportionality are also shown.

Gamma Ray Detection with Cd0.9Zn0.1Te Based Detectors Grown Using a Te Solvent Method

ABSTRACTCd0.9Zn0.1Te (CZT) single crystal has been grown using a tellurium solvent method. Two CZT crystals have been chosen from two different locations of the grown ingot. The two crystals were characterized using infrared transmission (IR) imaging and radiation detectors in planar geometry were fabricated on them. Current-voltage characteristics (I-V) revealed a resistivity of ∼8.6×1010 Ω−cm for detector A (6.9×6.9×4.8 mm3) and 6.7×1010 Ω−cm for detector B (11.5×11.7×2.6 mm3). IR imaging showed a lesser concentration of Te inclusions/precipitates in detector A. The transport properties viz., electron drift-mobility and electron mobility-lifetime product were measured using alpha spectroscopy in these detectors in a planar configuration. Detector A showed better charge transport properties compared to detector B. The superior transport properties of crystal A were reflected in the spectroscopic properties of the detectors. Gamma pulse height measurements using a 241Am isotope revealed an energy resolution of ∼5 % for detector A and ∼7 % for detector B. A digital spectrometer and a biparametric correction scheme was incorporated to recover the pulse height spectrum of high energy gamma rays (137Cs source) from the effect of poor hole movement.