Study on Properties of a Hybrid Photomultiplier Tube Based on a SiC Schottky Diode Combined with an MCP

Scintillation detector is one of the key detectors for measurements of pulsed radiation fields due to its high sensitivity and fast time response. In a scintillation detector, the photomultiplier tube (PMT) need have a high gain, a fast temporal response, and a large maximum linear current (MLC). The hybrid photomultiplier tube (HPMT) based on a SiC detector (SiC-HPMT) with a larger MLC is expected to become one kind of the important photon detectors for the measurements of pulsed radiation fields with a high intensity. However, the inherent problem is that the currently used hybrid photomultiplier is severely restricted by a low gain. On the basis of maintaining the original excellent properties, such as fast temporal response and large MLC, a novel HPMT (MCP-SiC-HPMT) which is composed of SiC-HPMT and a microchannel plate (MCP) is developed to offer an effective way to improve the gain. According to the experimental results, the influence laws of the accelerating and focusing voltage and the bias voltage of the SiC detector on its properties such as the gain, dark current, temporal response, and MLC were obtained. The gain and the MLC of the MCP-SiC-HPMT can reach over 10 and 500 mA, respectively. Moreover, the result demonstrated that the temporal response of the MCP-SiC-HPMT has a leading edge of about 2 ns and a FWHM of about 4 ns, which is almost same as that of the SiC-HPMT. The addition of the MCP does not only improve their gain but also has no significant impact on its excellent performance. The detector based on an EJ228 scintillator and the MCP-SiC-HPMT successfully measured the multiple peaks characteristic of a pulsed X-ray source, which indicated that the MCP-SiC-HPMT can well meet the requirements of the temporal characteristics measurement of a pulsed device. The detector combining a stilbene scintillator with the developed MCP-SiC-HPMT can well discriminate the neutron and gamma rays produced by a D-T neutron source. The successful development of the MCP-SiC-HPMT can further expand the applications in pulsed radiation field measurements and show the great potential in the field of particle detections for HPMTs.