Radiation detection circuit

Abstract

A radiation detection circuit having a multi-channel input used for radiation measurement and capable of canceling cross-talk noise generated from a logic circuit for controlling a channel and enabling low noise radiation measurement easily and precisely. The radiation detection circuit also generates an inverted signal for each of input/output signals needed for controlling its logic and cancels a noise charge generated by coupled capacity between a bonding wire (analog input side in IC package) for connecting its output to another radiation detection circuit and a bonding wire of each of input/output signals of the logic control circuit by generating an inverted noise charge with coupled capacity between the inverted signal and its output when in logic controlling, thereby suppressing the cross-talk noise generated by each of its input/output signals.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a circuit diagram of a detection unit including a radiation detection circuit of the present invention in an embodiment;

FIG. 2 is a circuit diagram to which the parasitic capacity of an analog signal detection block input part shown in FIG. 1 is added;

FIG. 3 is a time chart for showing how noise contents detected during a signal I/O operation are canceled each other;

FIG. 4 is a diagram for showing how LSI pads are disposed to reduce noise;

FIG. 5 is a time chart for showing how noise contents detected during I/O operations of signals are canceled each other;

FIG. 6 is a circuit diagram of a variation of a logic control side I/O circuit when the circuit potential differs from that of a logical control IC in a latter stage in a second embodiment;

FIG. 7 is a time chart for describing how noise contents detected during I/O operations of signals shown in FIG. 6 are canceled each other;

FIG. 8A is a diagram for describing a logic method for suppressing the number of output signals and control logic signals; and

FIG. 8B is a diagram for describing a logic method for suppressing the number of reset control logic signals.

Claims

1. A radiation detection circuit connected to an output side of a radiation detector, inputting a strong charge signal from said radiation detector according to an incident energy of radiation, and outputting incident energy information and incident timing information according to an intensity of said charge signal, wherein said radiation detection circuit is formed as a semiconductor integrated circuit on a single semiconductor substrate,wherein an inverted signal is generated for each of input/output signals required for controlling a logic of said radiation detection circuit, andwherein said radiation detection circuit is structured so that a noise charge generated by coupled capacity between a bonding wire at an analog input side in a package of said semiconductor integrated circuit and each bonding wire of said input/output signals is canceled by an inverted noise charge generated by coupled capacity between said inversed signal and said output of said radiation detector when in logic controlling.

2. The radiation detection circuit according to claim 1, wherein said inverted signal is disconnected from an external logic control circuit for controlling said logic.

3. The radiation detection circuit according to claim 1, wherein said radiation detection circuit is connected to output sides of two or more of said radiation detectors and formed as a semiconductor integrated circuit provided with a plurality of analog input signal processing blocks that are united into one on a single semiconductor substrate.

4. The radiation detection circuit according to claim 1, wherein said input/output signals include a digital input signal for reading and resetting, a digital output signal for transferring information related to a radiation detection time, and an analog voltage signal in proportion to said charge signal inputted from said radiation detector.

5. The radiation detection circuit according to claim 4, wherein said radiation detection circuit is controlled according to said digital input signal during radiation measurement.

6. The radiation detection circuit according to claim 4, wherein said digital output signal is output from said radiation detection circuit to an external logic control circuit when said charge signal exceeds a preset threshold to notify detection of radiation, andwherein said radiation detection circuit outputs information related to said radiation detection with use of said digital output signal to said external logic control circuit during radiation measurement.

7. The radiation detection circuit according to claim 4, wherein said analog voltage signal is output to an analog digital conversion circuit connected to between said radiation detection circuit and an external logic control circuit provided outside said radiation detection circuit, andwherein said analog voltage signal transfers an analog voltage signal of said block to be read during radiation measurement after said external logic control circuit reads information from said radiation detection circuit.

8. The radiation detection circuit according to claim 1, wherein said detector further includes a charge sensitive amplifier and a filter, andwherein said charge sensitive amplifier has functions for converting said charge signal to a voltage signal with a preset conversion gain, inputting said voltage signal to said filter when said voltage signal exceeds a preset voltage threshold, holding said voltage signal output from said filter as voltage information proportional to an intensity of said charge signal, and outputting said held voltage information, as well as a function for outputting incidental time information related to an incident time at which said radiation enters said radiation detector.

9. The radiation detection circuit according to claim 1, wherein the output impedance of said radiation detector and the input impedance of said charge sensitive type amplifier are higher than the output impedance of said radiation detection circuit respectively.

10. The radiation detection circuit according to claim 9, wherein the connection line between said radiation detector and said radiation detection circuit is electrically shielded.

11. The radiation detection circuit according to claim 1, wherein the line of said inverted signal and each line of said input/output signals are disposed adjacently, andwherein said inverted signal is used to generate an inverted noise charge for canceling noise charge generated by coupled capacity between an analog bonding wire for connecting an output of said radiation detector to an input of said radiation detection circuit to a digital bonding wire for connecting said radiation detection circuit to an external logic control circuit for controlling said logic.

12. The radiation detection circuit according to claim 11, wherein a position where each of said input/output signal lines and said inverted signal line are disposed adjacently is the farthest from said analog bonding wire for connecting said radiation detector output to said radiation detection circuit input on said radiation detection circuit.

13. A radiation detection circuit, comprising: an analog circuit part connected to an output side of a radiation detector; anda digital circuit part connected to an output side of said analog circuit part,wherein said analog circuit part has a plurality of analog input wires used to input a signal received from said radiation detector to said analog circuit part respectively,wherein said digital circuit part has at least one digital input wire used to input a signal received from said external logic control to said digital circuit part, at least one digital output wire used to output a signal generated by said digital circuit part to said external logic control circuit, and a dummy wire corresponding to each of said digital input wire and said digital output wire.

14. The radiation detection circuit according to claim 13, wherein said analog circuit part input side has an impedance higher than that of its output side.

15. The radiation detection circuit according to claim 14, wherein the input side of said analog circuit part includes a charge sensitive low noise amplifier.

16. The radiation detection circuit according to claim 13, wherein said analog circuit part and said digital circuit part are integrated into one on a single semiconductor substrate, andwherein said radiation detection circuit is formed as a semiconductor integrated circuit.

17. The radiation detection circuit according to claim 16, wherein said radiation detection circuit formed as said semiconductor integrated circuit and said external logic control circuit are united into one and mounted on a single circuit substrate.

18. A radiation detection circuit, wherein an analog signal processing block is divided into a plurality of groups;wherein a read clock and a select signal can be paired to search a radiation detected channel, andwherein said radiation detection circuit employs a read logic control method for suppressing the number of digital control signals to be assumed as noise sources.