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A new detector for PET using multi-pixel photon counters (MPPCs) was developed for MRI compatible applications. This module has an 8 × 8 MPPC array, each segment has a 3 mm × 3 mm active area, and the pitch of the array is 4.1 mm in both directions. A temperature sensor is attached to the back of the array for temperature compensation. The MPPC array is connected to the front-end circuit with a detachable...
Multi-Pixel Photon Counter (MPPC) is a solid state photon counting device consisting of Geiger-mode APD pixels and self-quenching resistors. The MPPC has attractive features, such as low bias voltage operation, high gain, compact size, robustness and insensitivity to magnetic fields. Therefore, MPPC applications are now being expanded, especially for very low light level measurements. We have developed...
Gamma ray cameras can easily locate radiation hotspots where decontamination is required. Among them, the Compton camera that utilizes the Compton scattering is compact and lightweight because no radiation shielding is required. We have developed a Compton camera for quick visualization of the radioactive contamination. It features high detection efficiency by utilizing gamma ray detectors which is...
For MeV gamma-ray Astronomy, we have developed an Electron Tracking Compton Camera (ETCC) as a next-generation MeV gamma-ray telescope. An ETCC consists of a three-dimensional electron tracker using a gaseous time projection chamber (TPC) and position-sensitive gamma-ray absorbers using pixel scintillator arrays (PSAs). We carried out the balloon borne experiment in 2006 with a small size ETCC and...
The Compton camera is a convenient tool used to visualize the distribution of radioisotopes that emit gamma rays. Following the nuclear disaster in Fukushima in 2011, there is a particularly urgent need to develop “gamma cameras”, which can visualize the distribution of such radioisotopes. In response, we propose a portable Compton camera, which comprises 3-D position-sensitive GAGG scintillators...
For MeV gamma ray astronomy, we have developed an Electron Tracking Compton Camera (ETCC) as a MeV gamma ray telescope in the next generation. Our detector consists of a gaseous Time Projection Chamber (TPC), which uses μ-PIC as the two-dimensional readout detector, and a position sensitive scintillation camera. We launched a small size ETCC with a 10 cm × 10 cm × 15 cm TPC loaded on a balloon in...
Modern x-ray CT systems measure the total energy of all photons incident to detectors, and thus it is very difficult to identify a medium with an x-ray CT image. We proposed a new method to identify a medium with an x-ray CT system, in which we used a detector that could measure photons with several energy windows. Our method identifies an object with a set of linear attenuation coefficients of the...
A 4π germanium spectrometer was developed for measurements of neutron capture cross sections of minor actinides and long-lived-fission products. It was installed on the Beam Line No. 04 of the MLF in the J-PARC. We measured its full-energy peak efficiency and gamma-energy resolution at 1.3-MeV with a 60Co standard source (10kBq). As an example of a result of TOF measurements with the spectrometer,...
To correct dead time in TOF experiments with multi-detector gamma-ray detection method, we have tested a dead-time correction method. In this dead-time correction method, random timing pulses generated by a random pulse generator are input to every pre-amplifier via test-signal inputs. Both the random timing pulses and the other pulses originated from gamma rays are measured with a data acquisition...
When an ultrasonic wave is applied to the end of a magnetic rod and a standing wave is generated, high frequency stress will be generated at the standing wave nodes according to the frequency of the ultrasonic wave. The change in magnetic moment generated by this high frequency stress can be easily observed with a detector coil. On the other hand, since stress is not generated at the positions of...
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