GB2209235A

GB2209235A - Radiation detection training

Info

Publication number: GB2209235A
Application number: GB8820316A
Authority: GB
Inventors: Peter Gerald Boid; Paul Thomas Dunham; Nicholas John Boid
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-08-28
Filing date: 1988-08-26
Publication date: 1989-05-04
Also published as: GB8720413D0; GB8820316D0

Abstract

Apparatus for training personnel in the detection of radio-activity, but without using a radio-active source, includes radio transmitter and a radio receiver which responds to signals received from the transmitter to simulate aspects of a geiger counter. The apparatus establishes the magnitude of a parameter, e.g. the distance between transmitter and receiver and/or the signal strength from the transmitter, and then expresses the magnitude of the parameter on a scale similar to that of a geiger counter and/or produces an intermittent sound similar to that of a geiger counter at a rate according to said magnitude.

Description

"IMPROVEMENTS IN OR RELATING TO TRAINING APPARATUS" This invention relates to training apparatus and more specifically to training apparatus for personnel being trained to detect, identify and record radiation levels.

The present practise in training personnel in radiation detection and measurement involves the use of a radiation source and a geiger counter, the radiation source is hidden from the personnel being trained and the source is traced using the geiger counter. This practise is most unpopular with many parties because of the hazards associated with radiation and is not popular with training personnel because with low level radiation sources the detectable levels are limited to very small distances.

The problem in the past has resided in finding a safe substitute for the radiation source and a substitute for the geiger counter and which substitutes would so duplicate the behaviour of a geiger counter responding to a radiation source as to constitute an effective training substitute.

The present invention seeks to provide a training apparatus capable of affording personnel realistic training in the detection, identification and measurement of radio-active sources.

Heretofore, personnel have been trained to detect radiation by the use of radioactive material and a geiger counter. While this provides very realistic training, it is nevertheless objectionable from the point of view that it could be hazardous due to the use of material that is radioactive.

It is an object of the present invention to provide training apparatus for effectively training personnel, but which, nevertheless, does not use radio-active material.

According to the present invention there is provided a training apparatus comprising a portable radio transmitter arranged to transmit radio signals of a predetermined characteristic and a portable radio receiver tuned to identify the signals emitted by the transmitter, the radio receiver being arranged to display the signals received from the transmitter in a manner simulating the display given by a conventional geiger counter detecting a radiation source.

Preferably, the predetermined character is that of frequency and, in the interests is simplicity of description, it will be assumed hereinbelow that the predetermined character is that of frequency.

Preferably the portable radio transmitter is arranged to emit radio signals on a frequency individual thereto and the portable radio receiver is tuned to identify only the signals emitted by its respective transmitter, whereupon a plurality of portable radio transmitters and portable radio receivers may be used simultaneously in the same training area.

Preferably the apparatus includes means for detecting and displaying the distance between the radio transmitter and the radio receiver.

In one embodiment in accordance with this aspect of the invention the circuitry of the apparatus is so arranged that the received signal strength increases as the receiver moves towards the radio transmitter and weakens as the radio receiver is moved away from the transmitter and this increase and decrease of the level of the received signal is translated to effect the desired display on the receiver.

In another embodiment the radio receiver includes a transmitter which transmits signals on a predetermined frequency; and the radio transmitter includes a receiver arranged to detect the signals transmitted by the radio receiver transmitter and to respond to the detected signals to transmit the radio transmitter signals which are detected by the radio receiver. The apparatus will further include a timer which will detect the time period between the emission of a signal from the radio receiver transmitter and receipt of the responding signal from the radio transmitter and will translate that timed period to effect the desired display on the receiver.

Preferably also the radio receiver includes an audible device, arranged to emit "clicks" simulating the clicks given by a geiger counter, and said audible device is controlled by the translation of the received signals so as to increase and decrease as the radio receiver moves closer to or moves away from the radio transmitter.

The invention will now be described further by way of example with reference to the accompanying drawings in which, Fig.l shows, diagrammatically, one embodiment for a training apparatus in accordance with the invention, Fig.2 shows, diagrammatically, a part of a second embodiment in accordance with the invention; being a diagram of a radio transmitter arrangement thereof and Fig 3 shows, diagrammatically, a further part of the second embodiment being a diagram a radio receiver arrangement thereof.

In the example illustrated in Fig. 1 the radio receiver arrangement is generally identified by reference numeral 11 and the transmitter arrangement is generally indicated by reference 12.

The radio receiver comprises generally a battery 13 which supplies power to a radio transmitter 14, a timer 15, a radio signal receiver 16, a visual display arrangement 17 and an audio arrangement 18.

The radio transmitter arrangement generally comprises a battery 19 which supplies power to a radio signal receiver 20 and a transmitter 21.

In training the radio transmitter 12 will be hidden in some location on the training area and the person in training will be physically carrying the radio receiver arrangement 11.

With both devices 11 and 12 activated the radio transmitter 14 of the radio receiver arrangement 11 will transmit signals, with a predetermined time interval therebetween controlled by a timer 14a associated with radio transmitter 14, via an aerial 14b on a predetermined frequency. Each signal transmitted via aerial 14b is detected by the radio receiver 20, via its aerial 20a. On receipt of a signal the radio receiver 20 activates the radio transmitter 21 to emit a signal on its predetermined frequency, via its aerial 21a.

Each signal transmitted by the transmitter 21 is detected by the radio signal receiver 16, via its aerial 16a. The timer 15, initiated on the emission of a signal by radio transmitter 14, records the time taken for the returning signal from transmitter 21 to be received by the radio signal receiver 16 and the said timer 15 transmits a signal indicative of the said time period to the visual display arrangement 17 and to the audio display arrangement 18.

It will now be seen that this particular embodiment operates in similar manner to the conventional RADAR or SONAR arrangements and whereby the time interval between a transmitted signal and a returned signal is used to measure the range of the target.

In the detection of radiation sources the radiation level of the source and the location of the source cannot initially be determined, the geiger counter simply records the radiation level at a given location, and the conventional method for locating the radiation source is by plotting the levels of detected radiation. In order to simulate the geiger counter the time periods detected by the timer 15 are translated to "levels" for the visual display arrangement and are also used to determine the rate of "clicking" by the audio display arrangement 18.

Thus, whilst the method of determining the distance between the radio receiver arrangement 11 and the radio transmitter 12 is essentially different from the actual measurement of radioactive levels by geiger counter the information given to the training personnel using the radio receiver 11 and transmitter 12 will be substantially identical to that as would be received by a geiger counter tracing a radio-active source.

In the example illustrated in Figs. 2 and 3, the radio transmitter generally comprises a battery 33 which extends power to a digital encoding circuit 34, a transmission timer 34a and a radio frequency transmitter, generally indicated as RFT. The digital encoding circuit 34 under the control of the timer 34a serves to modulate the radio carrier signal transmitted by the transmitter via its aerial RFTa. By using the digital encoding circuit 34 the signals transmitted by the radio transmitter can be substantially unique to that transmitter, whereupon a plurality of transmitters and receivers maybe used in the same training area without interfering with one another.

The radio receiver arrangement is a dual conversion superhet. It comprises a R.F. amplifier 38 to amplify the signal emitted by the transmitter RFT, a mix 39, a local oscillator 40, a frequency doubler 41 therefor; the mixer mixing the received amplified signal with the output of the doubler, a filter 42 to filter the output of the mixer, and a modular intermediate frequency (IF) unit 43 where further conversion takes place to demodulate the signal received by the IF unit.

The receiver arrangement further comprises to receive the demodulated signal from the IF unit, a digital decoder 44 to check that the received signal has the same digital identity as that of the receiver. If the digital code is valid, the signal strength levels from the IF unit are used to control an audio unit 46 and a visual display 47 providing the necessary user information. The arrangement also comprises a set 48 of voltage regulators to provide the voltages to the circuit stages, a crystal 49 providing a basic frequency input to the IF unit, a 455-KHz filter 50 to filter the output of the IF unit and a battery 51 to provide power to the arrangement.

Thus, with this arrangement, the receiver arrangement responds to the "strength" of the signals detected and again will translate"signal strength" to "detected level".

The present invention may be used not only for so-called "point source" detection but also for wide area detection and for personnel contamination detection.

In the case of wide area detection, the transmitter power would have to be greater than is generally needed in point source detection, and would entail the use of directional aerials or of buried cables, acting as aerials, in order to give a wide area simulation.

In the case of personnel contamination detection, using state of art miniaturisation, a very small, low powered, radio transmitter would be used, and several could be incorporated in the clothes of a contaminated person to simulate the characteristics of actual contamination. In a more elaborate arrangement, contamination of the kind that increases with exposure to a radio-active source is simulated. This entails using additional circuitry in one or the other of two ways, namely: INTERNAL TIMER (a) A timer and control unit is incorporated and would be initiated at the commencement of the training session. As time elapses (with the trainee within the training area) the radio transmitter output would increase and hence provide a greater detectable level.

INTERNAL TELECOMMAND RECEIVER (b) An internal receiver within the personnel contamination transmitter would be arranged to control the transmitter output power. The envisaged situation would allow a remote base station transmitter (on a separate radio frequency) under the control of a training supervisor, to alter the power levels as appropriate, by signalling the contamination transmitter telecommand receiver on its separate radio frequency.

Computer control of the contamination system could be used so that each trainee could be addressed separately by the system and thus allocated an individual dose rate.

Under both schemes, regular monitoring of personnel "radiation" levels would take place during the training session in order that trainees may be removed from the "danger zone" when the "exposure limit" had been reached.

A feature of radio-active materials is the decay of the radiation output with time. The"half life" of materials ranges from a few seconds to hundreds of years, depending on the radio-active material used.

In view of this, in a further development of the invention electronic circuitry is incorporated within the radio transmitter or radio receiver to reduce the output of the transmitter or sensitivity of the receiver to simulate the reduction of detectable levels with time. The time scales required would need to be investigated and would be preferably programmable by the end user in order that a more realistic training situation would be provided.

Whilst the present invention has been described by way of example with reference to specific embodiments the invention is not limited thereto and many modifications and variations will be apparent to persons skilled in the art.

Claims

1. A training apparatus comprising a portable radio transmitter arranged to transmit radio signals of a predetermined character and a portable radio receiver tuned to identify the signals emitted by the transmitter, the radio receiver being arranged to display the signals received from the transmitter in a manner simulating the display given by a conventional geiger counter detecting a radiation source.

2. Apparatus according to Claim 1, wherein the predetermined characteristic is that of frequency.

3. Apparatus according to Claim 1 or 2 wherein said transmitter is arranged to emit radio signals on a frequency individual thereto and the portable radio receiver is tuned to identify only the signals emitted by its respective transmitter.

4. Apparatus according to Claim 1, 2 or 3, wherein the apparatus includes means for detecting and displaying the distance between the radio transmitter and the radio receiver.

5. Apparatus according to Claim 1, wherein the predetermined characteristic is that of signal strength.

6. Apparatus according to Claim 5, wherein the circuitry of the apparatus is so arranged that the received signal strength increases as the receiver moves towards the radio transmitter and weakens as the radio receiver is moved away from the transmitter and this increase and decrease of the level of the received signal is translated to effect the desired display on the receiver.

7. Apparatus according to any of the Claims 1 to 4, wherein the radio receiver includes a transmitter which transmits signals on a predetermined frequency; and the radio transmitter includes a receiver arranged to detect the signals transmitted by the radio receiver transmitter and to respond to the detected signals to transmit the radio transmitter signals which are detected by the radio receiver.

8. Apparatus according to Claim 6, comprising a timer which will detect the time period of between the emission of a signal from the radio receiver transmitter and receipt of the responding signal from the radio transmitter and will translate that timed period to effect the desired display on the receiver.

9. Apparatus according to any of the preceding claims, wherein the radio receiver includes an audible device, arranged to emit "clicks" simulating the clicks given by a geiger counter, and said audible device is controlled by the translation of the received signals so as to increase and decrease as the radio receiver moves closer to or moves away from the radio receiver.

10 Apparatus according to any of the preceding claims 1 to 4 and 6 to 8, wherein the radio transmitter is connected to directional aerials and/or to buried cables acting as aerials.

11. Apparatus according to Claim 5 or 6, wherein the radio transmitter is constructed using minaturised circuitry.

12. Apparatus according to Claim 11, wherein the radio transmitter is provided in plurality.

13. Apparatus according to Claim 11 or 12, wherein the radio transmitter or each of them comprises a timer and control unit such that the radio transmitter can be operated to increase its power output with time.

14. Apparatus according to Claim 11 or 12, wherein the apparatus comprises a further radio transmitter to emit signals; and the radio transmitter is constituted with a receiver to receive those signals and in response thereto cause its radio transmitter to increase its power output with time.

15. Apparatus substantially as hereinbefore described with reference to Fig. 1 or to Fig. 2 and 3 of the accompanying drawings.