Radiation detection circuit and radiological imaging apparatus using the same
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G01T-001/24
G01T-001/00
출원번호
UP-0478728
(2006-07-03)
등록번호
US-7528375
(2009-07-01)
우선권정보
JP-2005-250521(2005-08-31)
발명자
/ 주소
Matsumoto, Takashi
출원인 / 주소
Hitachi, Ltd.
대리인 / 주소
Miles & Stockbridge P.C.
인용정보
피인용 횟수 :
5인용 특허 :
5
초록▼
There is a need for high-precision detection timing in a radiological imaging apparatus using a semiconductor detector so as to decrease time variations against a noise and easily correct process variations. A radiation detection circuit includes: a semiconductor detector; charge accumulation means
There is a need for high-precision detection timing in a radiological imaging apparatus using a semiconductor detector so as to decrease time variations against a noise and easily correct process variations. A radiation detection circuit includes: a semiconductor detector; charge accumulation means connected to the semiconductor detector; a circuit to discriminate timing of a signal generated from the charge accumulation means based on a specified threshold value; a shaper 1 to limit a band from the charge accumulation means using a first time constant; a shaper 2 to limit a band from the charge accumulation means using a second time constant; a circuit 1 to hold an analog peak value 1 for the shaper 1; and a circuit 2 to hold an analog peak value 2 for the shaper 2. The radiation detection circuit performs a signal process to generate timing correction data based on the analog peak values 1 and 2 and correct timing data from the timing discriminator circuit.
대표청구항▼
What is claimed is: 1. A radiation detection circuit that is connectable to an output side of a semiconductor detector and that allows the semiconductor detector to supply a current pulse signal having intensity corresponding to an input energy of radiation, and that outputs input energy informatio
What is claimed is: 1. A radiation detection circuit that is connectable to an output side of a semiconductor detector and that allows the semiconductor detector to supply a current pulse signal having intensity corresponding to an input energy of radiation, and that outputs input energy information and incident timing data of the radiation based on the current pulse signal intensity, wherein the incident timing data is generated from the current pulse signal caused by mobility of electrons and holes and from a predetermined threshold, and wherein a correction amount of the incident timing data depends upon a contribution of an electron and a contribution of a hole, and wherein said radiation detection circuit includes a filter having a time constant according to electron mobility and is constructed to acquire information about the contribution of electron from the current pulse signal intensity using the filter, and to output the information to a digital data correction circuit configured to correct the incident timing data by the correction amount. 2. The radiation detection circuit according to claim 1, wherein the incident timing data is output based on a result of a comparison performed by the radiation detection circuit between a voltage signal proportional to the current pulse signal intensity and a specified voltage threshold value. 3. The radiation detection circuit according to claim 2, wherein the incident timing data output includes a time error. 4. The radiation detection circuit according to claim 3, wherein information about the contribution of electron is output to the digital data correction circuit so that the digital data correction circuit corrects the time error. 5. The radiation detection circuit according to claim 2, wherein the specified voltage threshold value is generated inside the radiation detection circuit. 6. The radiation detection circuit according to claim 2, wherein the specified voltage threshold value is supplied from outside the radiation detection circuit. 7. The radiation detection circuit according to claim 1, wherein the radiation detection circuit has a function of maintaining a specified signal-to-noise ratio against a noise supplied from the semiconductor detector. 8. The radiation detection circuit according to claim 1, wherein process variations can be corrected for each input signal by calibrating the input energy information and the information about the contribution of electron. 9. A radiation detection circuit comprising: a charge-sensitive amplifier that is connectable to an output side of a semiconductor detector and that receives a current pulse signal with an intensity corresponding to a radiation input energy from the semiconductor detector, and that outputs a voltage signal proportional to the current pulse signal intensity; a first shaper that uses a first time constant larger than a hole transfer time in said semiconductor detector to limit and pass a band of a voltage signal output from the charge-sensitive amplifier; a second shaper that uses a second time constant equivalent in level to an electron transfer time in said semiconductor detector to limit and pass a band of a voltage signal output from the charge-sensitive amplifier using a filter having a time constant according to electron mobility; a first peak hold that holds an analog peak hold value for an output signal from the first shaper; a second peak hold that holds an analog peak hold value for an output signal from the second shaper; and a comparator that compares a voltage signal output from the charge-sensitive amplifier with a specified voltage threshold value and that outputs a comparison result as timing data, wherein the timing data is generated from the current pulse signal caused by mobility of electrons and holes and from a predetermined threshold, and wherein a correction amount of the timing data depends upon a contribution of an electron and a contribution of a hole, and wherein the radiation detection circuit is configured to correct the timing data by the correction amount, and wherein the radiation detection circuit is constructed to output to the digital data correction circuit a first analog peak value representing a peak value of an output signal from the first shaper and a second analog peak value representing a peak value of an output signal from the second shaper. 10. The radiation detection circuit according to claim 9, wherein the timing data is output based on a result of a comparison performed by the radiation detection circuit between a voltage signal proportional to the current pulse signal intensity and a specified voltage threshold value. 11. The radiation detection circuit according to claim 10, wherein the timing data output includes a time error. 12. The radiation detection circuit according to claim 11, wherein the second analog peak value is output to the digital data correction circuit so that the digital data correction circuit corrects the time error. 13. The radiation detection circuit according to claim 10, wherein the specified voltage threshold value is generated inside the radiation detection circuit. 14. The radiation detection circuit according to claim 10, wherein the specified voltage threshold value is supplied from outside the radiation detection circuit. 15. The radiation detection circuit according to claim 9, wherein the radiation detection circuit has a function of maintaining a specified signal-to-noise ratio against a noise supplied from the semiconductor detector. 16. The radiation detection circuit according to claim 9, wherein process variations can be corrected for each input signal by calibrating the first and second analog peak values. 17. A radiological imaging apparatus comprising: a semiconductor detector that is composed of a semiconductor device and that outputs a current pulse signal with an intensity corresponding to a radiation input energy; a charge-sensitive analog signal detection circuit that is connected to the semiconductor detector and that receives a current pulse signal output from the semiconductor detector, outputs first timing data representing a timing for a radiation to enter the semiconductor detector and first energy data proportional to an incident radiation energy, acquires first electron contribution energy data proportional to a ratio of electron contribution to the current pulse signal, by using a filter having a time constant according to electron mobility, and outputs the first electron contribution energy data; and a digital data correction circuit that inputs the first timing data, the first energy data, and the electron contribution energy data, that corrects timing for a radiation to enter the semiconductor detector by a correction amount, and that outputs corrected timing data, wherein the first timing data is generated from the current pulse signal caused by mobility of electrons and holes and from a predetermined threshold, and wherein the correction amount of the timing depends upon a contribution of an electron and a contribution of a hole. 18. The radiological imaging apparatus according to claim 17, wherein the digital data correction circuit includes a timing detection unit that is supplied with the first timing data output from the charge-sensitive analog signal detection circuit and converts the first timing data into second timing data in accordance with a clock signal synchronized with a system. 19. The radiological imaging apparatus according to claim 18, wherein the digital data correction circuit further includes a timing correction data table unit, wherein the timing correction data table unit is constructed to output a correction value for the second timing data based on second energy data generated by converting the first energy data into a digital value and based on second electron contribution energy data generated by converting the first electron contribution energy data into a digital value, and wherein third timing data is generated from the second timing data and the correction value. 20. The radiological imaging apparatus according to claim 18, wherein the digital data correction circuit further includes a timing correction operating unit, wherein the timing correction operating unit is constructed to calculate and output a correction value for the second timing data based on second energy data generated by converting the first energy data into a digital value and based on second electron contribution energy data generated by converting the first electron contribution energy data into a digital value, and wherein third timing data is generated from the second timing data and the correction value.
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이 특허에 인용된 특허 (5)
Valentin Jordanov, Digital pulse de-randomization for radiation spectroscopy.
Warburton William K., X-ray detector method and apparatus for obtaining spatial, energy, and/or timing information using signals from neighboring electrodes in an electrode array.
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