KR100437872B1 - Hybrid Semiconductor type Radiation Detector with Improved Safety - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor type complex radiation detector with improved safety, and its object is to provide a compact real-time electronic radiation detector with greatly improved safety and reliability in radiation measurement of a radiation worker.

According to the present invention, a semiconductor detector for detecting ionizing radiation (gamma rays and X-rays) includes a MOSFET sensor for detecting a cumulative radiation dose, a diode sensor for detecting an instantaneous radiation rate, and an output value from each sensor. It is characterized by consisting of a comparator to compare to the selected one of the instantaneous radiation dose or cumulative radiation dose after the conversion, and an alarm device that operates when an error abnormality occurs after the comparison.

Description

Hybrid Semiconductor type Radiation Detector with Improved Safety}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor type complex radiation detector with improved safety, and more particularly, to a small radiation detector including a sensor consisting of a pMOSFET chip and a diode and a comparator and an alarm device for comparing the same.

BACKGROUND ART Conventional semiconductor detectors for detecting ionizing radiation (gamma rays and X-rays) have been developed to measure cumulative amounts of radiation and instantaneous exposure radiation rates, respectively, using a MOSFET or diode.

In addition, a small complex radiometer may be implemented by implementing a PIN diode for detecting neutrons and a MOSFET for detecting gamma rays in a single measurement module in a mixed radiation environment with neutrons and gamma rays.

From the point of view of practitioners who must perform work in the radiation environment, malfunctions and failures of the radiation detector can result in catastrophic damage to the human body and, in the worst case, loss of life, so much emphasis cannot be placed on the reliability and safety of the radiation detector.

Until now, single radiation detectors or mixed radiation detectors are preventive measures against serious radiation accidents caused by malfunctions or failures of the radiation detector itself. This allows the radiation environment worker to wear and perform two or more different radiation detectors simultaneously. .

However, wearing multiple radiation detectors in addition to the uncomfortable protective clothing and equipment and additional work tools of workers who must be worn in a radiation environment not only reduces the operator's work efficiency but also frequently checks and compares multiple radiation detectors in the course of work. This procedure adds annoyance to the operator, and often causes the operator to ignore the procedure for checking the radiation exposure, which may cause an accident that has a fatal effect on the safety of the operator.

An object of the present invention for solving the above problems is to provide a small real-time electronic radiation detector with greatly improved safety and reliability in the radiation measurement of the radiation worker.

The object of the present invention as described above is to compare the two values by converting the output values of the composite radiation detector consisting of a metal oxide semiconductor field effect transistor (MOSFET) and a diode (Diode) and the two detectors to the same radiation rate (amount) It is achieved by providing a measuring device that prevents malfunction and failure of a radiation measuring sensor by informing a worker when an abnormality occurs.

1 is an embodiment showing a processing flow of a composite radiation detector consisting of the present invention MOSFET, diode, differentiator, etc.,

Figure 2 is an embodiment showing the processing flow of the composite radiation detector consisting of the present invention MOSFET, diode, integrator and the like.

<Description of the symbols for the main parts of the drawings>

(1): pMOSFET chip (2): diode

(3): Threshold Voltage (VT) (4): Converter

(5): instantaneous photocurrent (IP) (6): transducer

(7): Differentiator (8): Integrator

(9): comparator (10): alarm device

The configuration of the present invention, which achieves the above object and accomplishes the problem for eliminating the conventional drawbacks, is a semiconductor sensor for detecting ionizing radiation (gamma rays, X-rays) and a MOSFET sensor for detecting an accumulated radiation dose. It consists of a diode sensor for detecting the radiation rate, a comparator for comparing the output value from each sensor to one selected from the instantaneous radiation dose or the cumulative radiation dose after conversion, and an alarm device that operates when an error occurs after the comparison. It is done.

The composite detector comparing the measured values from each sensor with the instantaneous radiation dose includes a pMOSFET chip (1) providing cumulative exposure information of radiation and a threshold voltage that is output information of the pMOSFET (p-type metal oxide semiconductor field effect transistor). A pMOSFET sensor composed of a transducer 4 for converting VT, Threshold Voltage, 3) to a corresponding radiation accumulation value, and a differentiator 7 for differentiating the converted radiation dose value to provide an instantaneous radiation rate value;

A diode sensor composed of a diode (Diode) 2 for outputting the instantaneous photocurrent 5 by the incident radiation and a converter 6 for converting the radiation rate value corresponding to the output current amount of the diode;

A comparator (9) for comparing respective radiation rate values outputted to the two sensors and converted;

When the error of the two values in the comparator is a predetermined value or more is composed of an alarm device for providing the occurrence of the error to the operator.

The composite detector comparing the measured values from each sensor with the cumulative radiation dose includes a pMOSFET chip (1) which provides radiation accumulation amount information and a threshold voltage (output voltage) of the pMOSFET (p-type metal oxide semiconductor field effect transistor). A pMOSFET sensor comprising a converter 4 for converting VT, Threshold Voltage, 3) to a corresponding radiation accumulation value;

Integrate the diode sensor consisting of a diode (Diode, 2) for outputting the instantaneous photocurrent (5) by the incident radiation, and a converter (6) for converting the radiation rate value corresponding to the output current amount of the diode and A diode sensor composed of an integrator 8 providing a cumulative radiation dose value;

A comparator (9) for comparing the respective radiation dose values outputted to the two sensors and converted;

When the error of the two values in the comparator is a predetermined value or more is configured to the alarm device 10 to provide the occurrence of the error.

Hereinafter, the configuration and the operation of the embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows an embodiment showing a process flow of a composite radiation detector consisting of the MOSFET and diode, the differentiator of the present invention, the configuration of the present invention in constructing a composite radiation detector with improved safety, the semiconductor device pMOSFET chip ( p-type Metal Oxide Semiconductor Field Effect Transistor (1), diode (Diode, 2) chip, converter (4) which substitutes the cumulative exposure dose value corresponding to the threshold voltage of the MOSFET, and converts the value of the converted cumulative dose A pMOSFET sensor composed of a differentiator (Differentiator) 7 which provides a value of the emissivity by differentiation;

A diode sensor configured to convert the instantaneous photocurrent value into a corresponding radiation rate value upon incidence of radiation;

A comparator 9 for comparing the radiation rate values outputted and converted by the two sensors;

When the error of the two values in the comparator is a predetermined value or more is composed of an alarm device for providing the occurrence of the error to the operator.

Figure 2 shows an embodiment showing the processing flow of the composite radiation detector consisting of the MOSFET, diode, integrator, etc. of the present invention, the configuration of the present invention in the construction of a composite radiation detector with improved safety, a semiconductor device pMOSFET chip ( a pMOSFET sensor composed of a p-type Metal Oxide Semiconductor Field Effect Transistor, 1), a diode (Diode, 2) chip, and a converter 4 which is substituted with an exposure cumulative radiation dose value corresponding to an output voltage of the MOSFET;

A diode sensor composed of a transducer 6 which substitutes the instantaneous photocurrent value with the corresponding radiation rate value upon incidence of radiation, and an integrator 8 which provides a cumulative radiation dose value by integrating the converted instantaneous radiation rate value;

A comparator 9 for comparing the radiation rate values outputted and converted by the two sensors;

When the error of the two values in the comparator is a predetermined value or more is composed of an alarm device for providing the occurrence of the error to the operator.

The pMOSFET and diode can be used not only as a general electronic device but also a chip produced exclusively for radiation sensing, and in this case, it is advantageous to apply because the device has excellent sensitivity to radiation.

The cumulative radiation dose converter 4 and the instantaneous radiation dose converter 6 have a threshold voltage of the MOSFET with respect to the irradiation dose obtained in an experiment in a radiation field similar to that for which each semiconductor (MOSFET, diode) is to be measured. It is obtained by applying the relation function of the amount of photocurrent of a diode with respect to the radiation rate, and since this function has unique characteristics for each semiconductor, the experimental value in the radiation field is determined accordingly.

Appropriate values may be applied depending on the radiation tolerance of the operator with respect to the radiation environment using the comparison reference value in the comparator 9 and the definition of the radiation environment to be measured.

And the alarm 10 device applies an efficient way to deliver to the worker using sound, light, or vibration.

Although the present invention is generally made of silicon (Si), which is the same material, the reason for using MOSFETs and diodes, which are semiconductor devices having different functions, is that the mechanisms in which the two devices react to ionizing radiation are fundamentally different.

That is, in the case of a diode, when the ionizing radiation is incident, the charge generated by the radiation in the body used as a path for current forms an instant photo current pulse by an external reverse bias, whereas the pMOSFET The output threshold voltage of the pMOSFET changes due to the positive charge that is accumulated and separated by the incident radiation inside the oxide layer irrelevant to the passage of current, which is located on top of the gate layer. It has a characteristic.

In addition, the photocurrent generated in the diode by radiation disappears through an external load line in a short time as a momentary pulsed current, and can provide dose rate information, which is an instantaneous change in incident radiation, The charge generated in the gate oxide layer of the pMOSFET by radiation accumulates inside the oxide layer, so that the value of the threshold voltage of the pMOSFET changed by this charge provides a cumulative information of the dose of the exposed radiation.

The differential value of the cumulative radiation dose obtained from this pMOSFET is converted into information of the instantaneous radiation rate.

In the measurement of the same radiation as described above, a worker in a radiation environment is malfunctioned by a method of comparing the same radiation rate information obtained by using a semiconductor radiation sensor having two different radiation response mechanisms. And fault status can be checked accurately and easily.

This is because the principle of redundancy and diversity applied to the design of nuclear power plants, which consider safety as the most important factor, is to realize the probability of failure by implementing a single function using a plurality of components of different mechanisms. Minimized concept) greatly improves the reliability and safety of operators.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

The present invention as described above is applicable to nuclear power generation facilities, such as nuclear power plants and radiation tests, in particular in patients treatment facilities and high-level radiation work environment where safety is very emphasized.

In addition, since the present invention is composed of a small semiconductor device and an electronic device, it is possible to increase the safety when commercializing the present invention by simultaneously removing the inconvenience of the operator's wearing and the possibility of unconscious unconscious loss of information in a complicated radiation working environment. This is the invention which industrial use is expected.

Claims (3)

In the semiconductor detector for detecting ionizing radiation (gamma rays, X-rays), MOSFET sensor for detecting the cumulative radiation dose, diode sensor for detecting the instantaneous radiation rate, comparator comparing the output value of each sensor with one selected from the instantaneous radiation dose or the cumulative radiation dose after conversion, and the error determined after the comparison The semiconductor type radiation detector with improved safety, characterized by comprising an alarm device that operates when an abnormality occurs. The method of claim 1, The composite detector comparing the measured values from each sensor with the instantaneous radiation dose includes a pMOSFET chip (1) providing cumulative exposure information of radiation and a threshold voltage that is output information of the pMOSFET (p-type metal oxide semiconductor field effect transistor). A pMOSFET sensor composed of a transducer 4 for converting VT, Threshold Voltage, 3) to a corresponding radiation accumulation value, and a differentiator 7 for differentiating the converted radiation dose value to provide an instantaneous radiation rate value; A diode sensor composed of a diode (Diode) 2 for outputting the instantaneous photocurrent 5 by the incident radiation and a converter 6 for converting the radiation rate value corresponding to the output current amount of the diode; A comparator (9) for comparing respective radiation rate values outputted to the two sensors and converted; Safety-enhanced semiconductor composite radiation detector, characterized in that configured as an alarm device for providing the operator of the error when the error of the two values in the comparator more than a predetermined value. The method of claim 1, The composite detector comparing the measured values from each sensor with the cumulative radiation dose includes a pMOSFET chip (1) which provides radiation accumulation amount information and a threshold voltage (output voltage) of the pMOSFET (p-type metal oxide semiconductor field effect transistor). A pMOSFET sensor comprising a converter 4 for converting VT, Threshold Voltage, 3) to a corresponding radiation accumulation value; Integrate the diode sensor consisting of a diode (Diode, 2) for outputting the instantaneous photocurrent (5) by the incident radiation, and a converter (6) for converting the radiation rate value corresponding to the output current amount of the diode and A diode sensor composed of an integrator 8 providing a cumulative radiation dose value; A comparator (9) for comparing the respective radiation dose values outputted to the two sensors and converted; Safety-enhanced semiconductor composite radiation detector, characterized in that configured as an alarm device for providing the operator of the error when the error of the two values in the comparator more than a predetermined value.