Field of the Invention

The invention relates to ionizing radiation measurement technique, in particular, to the devices with a silicon-based PIN diode as the detector of ionizing radiation. Owing to silicon detectors, such devices, while operating at room temperature, feature sufficiently high sensitivity. Silicon detectors are widely used in both household and industrial dosimeters-radiometers.

As fissile materials and ionizing radiation find more diverse applications in medicine and disease prevention, and as penetration of mobile phones / smartphones and computers exceeds the population of the earth, there emerges a need for devices with built-in sensors and detectors of ionizing radiation of various nature and range.

To this end, an obvious need arises for an immediately available to virtually any user and systematic monitoring and control of the environment, air and food products to detect fissile materials penetration by a variety of ways and under diverse circumstances. Besides, in the areas of nuclear testing and man- induced disasters involving fissile materials, the latter may contaminate not only the air, but also the soil, vegetation, groundwater, seawater and seaweed, as well as various animals and birds used as human food, while man is not capable of sensing ionizing radiation throughout its spectrum and intensity.

Prior Art

PIN diodes are used in the known present-day devices with the dosimeter- radiometer function as the detectors of ionizing radiation to convert into proportional voltage the charge generated in the silicon detector under ionizing radiation during a particle transit, for which purpose the charge amplifier (charge- sensitive amplifier - CSA) is used with the conversion factor of about V/pC and the response rate of about 1 μςεο. Further signal amplification is achieved by a voltage amplifier so that the total voltage gain is about 10 to the power of five. Under such conditions, the device detecting ionizing radiation becomes susceptible to various electromagnetic interferences. This is particularly apparent where the device operates near sources of intensive electromagnetic radiation, such as smartphones. Besides, a silicon detector of ionizing radiation generates charge by itself when exposed to mechanical effects in the form of shocks and vibration or to external noise.

These factors decrease the accuracy of ionizing radiation measurements increasing the number of spurious impulses caused by various interferences.

The problem of noise and electromagnetic interferences is solved in the known devices by shielding the silicon detector of ionizing radiation and the charge-sensitive amplifier (CSA), as well as by filtering, optimum arrangement of the electrical elements and rational PCB wiring. In this case, it is much more difficult to eliminate the interference caused by exposure of the ionizing radiation detector to noise and mechanical effects. Mechanical protection of the detector increases the device dimensions, which is unacceptable for compact integrated devices used for exact measurement of the ionizing radiation parameters.

There is a known modular semiconductor radiation dosimeter-radiometer integrated into a radio unit and connected to an amplifier and an interface unit, with its output switched to a processor capable of forming audio and visual dosimeter and radiometer signals using the aforementioned means of signaling and a display (RU 109625).

There is a known compact embeddable (modular) dosimeter-radiometer of ionizing radiation containing a p-i-n diode radiation detector with heavily-doped p- and n-regions created in lightly-doped semiconductor silicon, control and data transfer interface, calibrator, voltage converter and an integrated circuit comprising: series-connected charge-sensitive amplifier, shaping amplifier, spectrometer based on an amplitude-to-digital converter and comparator, and a microprocessor connected to a control and data transfer interface adapted for connection to the information and power buses of a mobile device, while the microprocessor is connected with a calibrator and a voltage converter and the latter is connected to a radiation detector switched to the charge-sensitive amplifier. The dosimeter-radiometer is provided with a compact case, may be promptly installed in a communicator mobile device, such as smartphone, tablet computer or a laptop, and is equipped with autonomous power supply, while the chip is uncased. The dosimeter-radiometer includes a successive approximation ADC and a set of threshold synchronization comparators and peak detectors. The dosimeter-radiometer is equipped with a wireless communication interface, such as Bluetooth, hybrid Bluetooth, Bluetooth Low Energy or Near Field Communication (NFC) connected to the microprocessor (RU 145480, prototype).

The weak point of known dosimeters-radiometers is their low accuracy due to the noise interferences caused by mechanical effects. The interference caused by mechanical effects is associated with elastic vibrations of the detector and is a periodic signal whereas a particle generates a single pulse signal. Besides, the known devices do not monitor spectral characteristics.

Summary of the Invention

The engineering problem of the invention is to create an effective universal miniature dosimeter-radiometer-spectrometer for detection of a wide spectrum of ionizing radiation from all types of charged particles and gamma ray quantum within a wide range of energies and flows, as well as their energy characteristics, which is designed as a universal compact module, embeddable into various electronic devices ensuring extended applicability of such solutions in the present-day consumer devices and expansion of the dosimeter-radiometer range.

The technical result ensuring solution of this problem is in increasing the accuracy owing to separation and recording of signals caused by external physical factors, in particular, by electromagnetic noise and/or vibrational mechanical effects determining of their amplitude and oscillation period, and digital filtering to exclude such signals from the relevant impulses. In the claimed device, the interference caused by mechanical effects is excluded comprehensively by both hardware and software means without resorting to mechanical protection. Altogether there is a decrease in the detector susceptibility to external disturbances, increased immunity to interferences resulting from external physical factors such as noise, vibration or electromagnetic oscillations both technogenic and natural. At the same time, this solution minimizes the size and weight of the device. In addition, the solution ensures expansion of the range of detected energies and the possibility to detect various types of ionizing radiation, including their spectral characteristics and isotope portraits, which, in turn, enables more precise definition of EDR and ED.

The essence of the invention is that the miniature dosimeter-radiometer- spectrometer contains at least two parallel measuring channels, each comprising a silicon detector of ionizing radiation with a voltage converter, the output of which is connected to the input of a controlled charge-sensitive amplifier, the output of the latter being connected to the input of a shaping amplifier, and the output of the latter - to the input of an amplitude-to-digital converter comprising a spectrometer circuit with a set of comparators; a calibrator is connected to charge-sensitive amplifiers of all measuring channels and the outputs of the amplitude-to-digital converters of the measuring channels are connected via a solver to a wireless communication interface.

In particular cases, the solver is designed with logical element "AND" and logical element "exclusive OR" and ensures the possibility to evaluate magnitudes and calculate the time interval between pulses, as well as separate the signals received during a particle transit or exposure to noise interference or mechanical effects.

In other particular cases, the solver is a microprocessor capable of evaluating magnitudes and calculating the time interval between pulses, as well as separating the signals received during a particle transit or exposure to noise interference or mechanical effects.

The dosimeter-radiometer-spectrometer is preferably connected via a wireless communication interface, such as Bluetooth, Wi-Fi, NFC, USB or

AudioJack 10, with an information device, such as a mobile phone, smartphone, tablet computer or a personal computer.

The dosimeter-radiometer-spectrometer is preferably equipped with an adjustable reference voltage source connected to both of the amplitude-to-digital converters, which enables setting of the reference signal level (detection threshold) for each of the amplitude-to-digital converter comparators. The dosimeter-radiometer-spectrometer is preferably designed as a circuit board or a hybrid microassembly and is equipped with a power unit for detectors.

The dosimeter-radiometer-spectrometer is preferably provided with an individual compact case that can be promptly installed in mobile information device, while the radiation detector is a p-i-n diode manufactured by planar technology with heavily-doped p- and n-regions created in lightly-doped semiconductor silicon.

The dosimeter-radiometer-spectrometer is preferably equipped with internal memory for storage and transfer of information to an information device, either on demand or as scheduled.

The dosimeter-radiometer-spectrometer is preferably capable of producing sound, voice, text and color, vibration alarms and message signals based on automatically or manually pre-set parameters of dose rate or equivalent dose, established for a particular region or country.

The dosimeter-radiometer-spectrometer is preferably equipped with means for locating the source of ionizing radiation within the GPS / GLONASS geo- coordinates and defining the height of the measurement point above sea level, and preferably ensures recording on the device display or in the flash memory of the dose rate, equivalent dose, isotope name and spatial geo-coordinates marked on the photo or video images taken by the mobile information device.

Short description of drawings

Fig.1 is a schematic block-diagram of the miniature dosimeter-radiometer- spectrometer; fig.2 is a schematic block diagram of the basic programs for specialized software of the miniature dosimeter-radiometer-spectrometer.

Detailed Description of the Invention

The miniature dosimeter-radiometer-spectrometer includes at least two parallel measuring channels with digital noise suppression, each comprising a silicon detector 1 of ionizing radiation with a voltage converter (not shown), its output is connected to the input of a controlled charge-sensitive amplifier 2, the output of the latter being connected to the input of the shaping amplifier (SA) 3, and the output of the latter - to the input of an amplitude-to-digital converter comprising a spectrometer circuit with a set of comparators (not shown). The radiation detector 1 is a p-i-n diode manufactured by planar technology with heavily-doped p- and n-regions created in lightly-doped semiconductor silicon. A calibrator 7 is connected to the charge-sensitive amplifiers 2 of all the measuring channels, and the outputs of the amplitude-to-digital converters 4 of the measuring channels are connected via a logical solver 6 to a control and data transfer interface 9 and to a wireless communication interface 10, such as: Bluetooth (or hybrid Bluetooth, or Bluetooth Low Energy), Wi-Fi, NFC, USB, or AudioJack 10.

The solver 6 is designed with logical element "AND" and logical element "exclusive OR" (not shown) or in the form of a microprocessor ensuring evaluation of the magnitudes and calculation of the time interval between pulses and separation of the signals received during a particle transit or exposure to noise interference or mechanical effects.

The dosimeter-radiometer-spectrometer is connected via a wireless communication interface 10, such as Bluetooth (or hybrid Bluetooth, or Bluetooth Low Energy), Wi-Fi, NFC, USB, or AudioJack 10, with an information device (not shown), such as a mobile phone, smartphone, tablet computer, personal computer or another gadget.

The dosimeter-radiometer-spectrometer is equipped with an adjustable reference voltage source 5 connected to the comparators of both amplitude-to- digital converters 4, which enables setting of the reference signal level (detection threshold) for each comparator of the amplitude-to-digital converters 4.

The dosimeter-radiometer-spectrometer is designed as a circuit board or a hybrid microassembly and is equipped with a power unit 8 for detectors 1.

The dosimeter-radiometer-spectrometer is provided with an individual compact case (not shown) that can be promptly installed into a mobile information device.

The dosimeter-radiometer-spectrometer is equipped with internal memory (not shown) ensuring storage and transfer of information to an information device, either on demand or as scheduled. The dosimeter-radiometer-spectrometer is capable of producing sound, voice, text and color and vibration alarms and message signals based on automatically or manually pre-set parameters of dose rate or equivalent dose determined for a particular region or country.

The dosimeter-radiometer-spectrometer is equipped with means (not shown) for locating the source of ionizing radiation within the GPS / GLONASS geo-coordinates and defining the height of the measurement point above sea level, and ensures recording on the device display or in the flash memory of the dose rate, equivalent dose, isotope name and spatial geo-coordinates marked on photo or video images taken by the mobile information device.

The claimed device can be designed as a separate independent unit not limited to the master part that ensures detection of the exposure to radiation, vibration and impact force; in this case the device may contain a solver 6, which is a microprocessor ensuring analysis of the information received from the detectors 1 , decision making and output of the information to a built-in indicator device, a memory storage and various interfaces (RS232, USB, BTNFC etc.) for transmitting the stored information to a computer. The device can be configured as a separate unit connectable to a smartphone (mobile phone), tablet or a computer via various interfaces, both wireless (BT, NFC, Wi-Fi) and wired (RS- 232/422/485, USB, audio-jacks, etc.). In this case, some of the solver unit 6 (analysis of the signal appearance and shape) functions may be given over to the processor of the smartphone, or tablet computer. In this case, it is also possible to use the display of the smartphone or tablet computer as the information output and visualization unit.

The device can be configured as a module or unit, structurally embedded into a smartphone, tablet, computer or other mobile or stationary equipment with an intelligent device (such as car video recorder, car audio, etc.). In this case, the device can be connected not only via the above interfaces, but also directly to the bus of the intellectual device, wherefore a large part of the signal processing functions can be given over to the main processor of the intelligent device fitted with the appropriate software. The miniature dosimeter-radiometer-spectrometer is operated as follows:

As a part of a master information appliance, such as a smartphone or a tablet, the claimed dosimeter-radiometer-spectrometer is powered from the power supply facilities of the unit.

The signal from each radiation sensor 1 enters the input of the respective amplifier 2 converting the charge generated by the radiation sensor 1 into voltage.

The signal from output of each charge amplifier 2 enters the input of the respective shaping amplifier 3 where it is shaped as required for the operation of comparators of the amplitude-to digital converter 4, whereas the reference voltage source 5 defines the detection threshold and may be adjusted.

The reference level of the signal of one of the converter 4 comparators is selected based on the minimum signal level during a particle transit. The reference level of the comparator of another converter 4 is selected based on the interference level resulting from exposure of ionizing radiation detector 1 to mechanical effects.

By means of the comparators, the ADC 4 implements a circuit for the spectrometer mode that ensures assessment of isotopic composition of the fissile material by its spectral characteristics.

Each comparator of the converters 4 converts the signal received from the shaping amplifier into a logic signal entering the solver 6 inputs.

Calibrator 7 shapes the reference test pulses for automatic adjustment of the device in both the dosimeter-radiometer and spectrometer modes.

If the solver is configured as a logic solver based on logical elements "AND" and "exclusive OR", the elements function as follows:

The logical element "AND" has an output voltage when there are signals at both inputs. In the digital channel, the "AND" function is equal to one, if all its arguments (input signals) are equal to one.

The "exclusive OR" logical element (e.g., comparison circuit of two logical signals) has a low output voltage when both input signals are identical. If the input signals differ, the output voltage is high. In the digital channel, the "exclusive OR" function (XOR) is equal to one if only one of its arguments (input signals) is equal to one.

Thus, the logical solver 6 counts the number of impulses over a certain time interval and prepares the processed data for further transmission via a preset interface 9 or 10. The unit 6 also records periodic actuations of the converter 4 comparators, the time interval between the impulses of the comparators of each of the converters 4 and the actuations sequence of the comparators of the converters 4.

If the logical solver 6 is configured as a microprocessor, the latter counts the number of impulses over a certain time interval and prepares the processed data for further transmission thereof via a preset interface 9 or 10. The microprocessor of the unit 6 also records periodic actuations of the converter 4 comparators, the time interval between the impulses of the comparators of each of the converters 4 and the actuations sequence of the comparators of the converters 4.

The data are transmitted to the master device incorporating the dosimeter- radiometer-spectrometer by the interface 9 via a selected I2C or RS485, RS232, CAN 2.0, USB - 7, RS232, USB or BTNFC interface.

Under a radiation exposure with a reasonable dose rate, the resultant signal can appear only in one channel, the respective probability being 0.999999 (the 1 ,000-fold increase of the dose rate will reduce this value to 0.999). At the same time, electromagnetic pickup and vibration interference will induce similar signals in both channels. Thus, the claimed solution ensures reliable "separation" of the radiation-induced signal from interfering noises, both mechanical and electric. The possible use of even larger number of channels may ensure further improvement of signal filtration (without using a built-in microcontroller).

For both versions of the device 6, the sensors 1 and the solver 6 ensure digital filtering of the signal from noise pickup and mechanical effects.

In case of an integrated modular dosimeter-radiometer-spectrometer of ionizing radiation, batteries and units for charging thereof are excluded. Present- day hardware components allow achieving minimum dimensions of an embeddable device.

Any configuration of the claimed device is mainly a functional expansion of a mobile device comprising a processor, a GPS / GLONASS navigator determining the current geo-spatial coordinates of the inspected site and a Wi-Fi, GPRS, Bluetooth, or NFC3 transmitter-receiver. Batteries and memory block are mandatory basic components of the mobile device. Photo / video camera enables photo and video recording of the measuring object, keyboard 6 ensures interaction with software of the mobile device and display 8 is meant for displaying the results of software operation and measurement modes of equivalent dose rate and equivalent dose, as well as for identification of the source of ionizing radiation.

The claimed device allows measuring of ionizing radiation equivalent dose rate (EDR) and equivalent dose (ED), in particular, under exposure to X-rays, gamma rays, beta particles and alpha particles, as well as the spectrum of radioactive (fissile) material, which, in turn, can provide a distinct "portrait" of the ionizing radiation source, thus ensuring a more accurate measurement of the EDR and ED and identification of the hazard source. The device allows detecting exposure to shocks, noise and / or vibration.

The device allows mapping of the inspected site background radiation and radioactive contamination. A smartphone or a computer enable photo and video recording of the sites with high background radiation (dose rate) and determining of planar geo-coordinates thereof or spatial geo-coordinates for above the ground locations within the spatial geo-coordinates based on the conventional global standard above sea level. Besides, the device can alert the user by voice, text, color, sound and vibration to excessive ionizing radiation EDR and ED levels as calculated for the given region and country, with account for applicable specialized radiation safety standards for various citizen categories, such as civil population, NPP professional and technical staff, members of the military, etc.

The claimed dosimeter-radiometer-spectrometer is the first miniature consumer device ensuring not only evaluation of the dose rate and equivalent dose, but also diagnosis of the energy characteristics of ionizing radiation sources. It is also possible to determine the isotopic composition of an ionizing radiation source. Evaluation of isotopic composition of a radiation source is based on the spectra signatures of known radioactive (fissile) materials recorded in the flash memory of the application-specific integrated circuit.

Implementation of this technical solution ensures significant increase in the measurement accuracy owing to separation and recording of the signals caused by external physical factors such as electromagnetic and / or mechanical vibration interferences, determining the amplitude and period of oscillation thereof and digital filtering for exclusion of such signals from the relevant pulses. The interference caused by mechanical effects in the claimed device is excluded comprehensively by both hardware and software means without resorting to mechanical protection. Altogether there is a decrease in the detector susceptibility to external mechanical effects, increased immunity to interferences resulting from external physical factors such as vibration or electromagnetic oscillations, both technogenic and natural.

Industrial Applications

The present invention is embodied with multipurpose equipment extensively employed by the industry.