JPS58168982A - Radiation detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation detector that detects radiation such as X-rays and γ-rays at each of a large number of sampling positions.

For books that require a large number of spatial samplings, such as X-ray CT devices (conbeater tomography devices) and ECT devices (emission type combinator tomography devices*, There is a membership fee for using a combination with a photoelectric converter such as a photomultiglare, which is one of the reasons for the high price.

In view of the above, the present invention reduces only the number of photoelectric converters with respect to the spatial sampling number of radiation.
The purpose of the present invention is to provide a radiation detector that can be used at a low cost.

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. In the figure, N11-? Three adjacent scintillators 1 among a large number of scintillators made of BGO etc.
1.12.13 is connected to two PMT31e32 by the id 21 to 24, and the scintillator 11.13
The light outputs of scintillator 2 are sent as they are to PMT31.32, and the blue light outputs of scintillator 2 are sent to PMT31.
It is designed to be sent to each of the 32 locations. and P
The outputs of the MTs 31 and 32 are amplified by amplifiers 41 and 42, and then sent to a wave height discriminator 51 and 53. In addition, the outputs of the amplifiers 41 and 42 are summed by a summing amplifier 43, and
The mother pulse is sent to the wave height discriminator 52.

Here, if the respective optical outputs of the scintillators 11, 12, and 13 are a, b, and c, the outputs of the PMT 31 and the amplifier 41 and the outputs of the PMT 32 and the amplifier 42 are a, respectively.
+ ' b , c + Jz b K, and the output of the summing amplifier 43 corresponds to a + b + c. The arm pulse height discriminators 51 to 53 are for discriminating the wave height of the input pulse corresponding to the energy of the radiation to be detected, and the lower limit value is set to, for example, 70 degrees of the pulse height of the radiation having the energy to be detected. . Then, the /IP pulse height discriminator 51 detects only the pulse corresponding to scintillation in the scintillator 11, and the /IP pulse corresponding to the scintillation violation in the scintillator 12 is not detected because its peak value becomes a liability. The Norse wave height discriminator 51 detects the scintillation wave of the scintillator 11. Similarly, Quantity Luss wave height discriminator 53 pieces scintillator 1
Detect only the scintillation at 3. On the other hand, the input of the Jars wave height discriminator 52 is i(a
+b+c, so even if scintillation occurs in any of the scintillators 11 to 13, the pulse height will exceed the lower limit; however, the pulse height discriminator 51.
When a detected signal is generated from 53, the dulse wave height discriminator 52 is prohibited from outputting the detected medium signal, and the scintillation in the scintillator 12 is changed to 21.
Only the nine detected t4 pulses are output. In this way, detection pulses indicating that radiation is incident on each of the scintillators 11 and 12.13 can be obtained from the pulse height discriminators 51, 52, and 53. In other words, two or three PMTs can distinguish radiation incident on three scintillators.

Note that the light guides 21 to 24 can be constructed from fiber-like or block-like light guides. In order to stably derive each light output from the output surface of the scintillator 2 using the light guides 22 and 23, instead of dividing this output surface into parts, the ends of the light guides 22 and 23 are finely separated, and each It is preferable to arrange the light guide so that it is distributed over the entire output surface.Similarly, on the input surfaces of PMTs 31 and 32, it is better to have the light guide distributed over the entire surface rather than unevenly distributing the ends of the light guide to stably input the light output. It is preferable that it can be done.

As described above with respect to the embodiments, according to the present invention, the number of scintillators is required to correspond to the number of spatial samplings, but the number of photoelectric converters such as PMTs is required to correspond to the number of spatial samplings. can be reduced. Therefore, it is possible to reduce the cost by reducing the number of photoelectric converters while maintaining the same number of spatial suns/rings.

[Brief explanation of drawings]

The figure is a block diagram of one embodiment of the present invention. 11.12.13...Scintillator 21-24...Light guide 31.32...PMT 41, 42...Amplifier 43...Summing amplifier 51-53...Medium pulse wave height discriminator application People Shimadzu Corporation

Claims (1)

[Claims] (1) The light output of the first scintillator is directly applied to the first scintillator.
The light output of the second scintillator is guided to a photoelectric converter, the light output of the second scintillator is guided to the first charging converter and the second photoelectric converter, and the light output of the third scintillator is directly converted to the second photoelectric converter. 1. Second. a third scintillator; and the first scintillator. A light guide is connected between the second photoelectric converter and the first photoelectric converter. A radiation detector in which the output of the second photoelectric converter and the summed output of these two outputs are each guided to a Norse wave height discrimination circuit.