widely used in industrial nondestructive testing, nuclear power plants, nuclear submarines, isotope applications cobalt treatmen

 

1.Detector: It uses highly sensitive GM counter tube for energy compensation, thus reducing the difference between high and low energy responses. The counter tube transforms γ-ray into electric pulse signals, which are input into the MCU.

2.MCU: The MCU is an 8-bit MCU with LCD drive, which features high speed, low voltage, low power, single power supply, bus clock 0-4MHz, and LCD drive 4×32. The MCU performs all digital processing functions: pulse counting, calculation display, timebase creating, output of alarming signals, etc.

3.Display: The display is a special 4 comment and segments LCD, which clearly displays four figures and some characters. The full display of characters is as follows:

RATE---dose rate; ALARM---alarm; DOSE---dose; ON---dosimeter working indication; LOBAT---low-voltage indication; BLOCK---blocking dose alarm; mSv/hμSv/h---measure unit.

4.Alarm: The alarm circuit is composed of LED and buzzer. When the threshold is overrun, it sends out sound and flashes.

5.Press buttons: There are two press buttons on the device. One is the working switch, which controls high voltage. When it is on, high voltage is output to the counter tube. When it is off, there is no display of ON, high voltage is not output, and the device stops working. The other is the display switchover button MODE, which is pressed to switch the display between DOSE and RATE.

6.High-voltage power supply: two pieces of 1.5V dry batteries for the DC transformer to produce high voltage, which is provided to the counter tube.

Technical specifications

1.     Detector: GM counter tube, measure x-ray or γ-ray.

2.     Display range:4-bit LCD.

Accumulative dose equivalent: Hp (10) 0.0μSv99.99mSv.

Dose equivalent rate: Hp(10)0.1μSv/h99.99mSv/h.

3.     Response time: 3.6s36s.

4.     Dose rate response: <±20% (1μSv/h99.99mSv/h).

5.     Energey response: <±30% (50KeV1.3MeV)

6.     Relative deviation: <±20% (127Cs).

7. Alarming function and alarming threshold: Alarming threshold can be set in the range of dose rate and accumulative dose. This device currently provides the following fixed thresholds:

Accumulative dose :a short buzz and a flash for each rise of 0.1μSv; when it is ≥50μSv, the light and sound alarming lasts about 5s, and ALARM is displayed.

Dose rate: when it is ≥25μSv/h, the light and sound alarming lasts approximately 6s, and ALARM is displayed.

Block alarming: when the counter tube is blocked, the alarming lasts constantly, and ALARM is displayed; the intensity of the alarming sound is around 80dB at 30cm.

8.Low voltage indication: When the battery voltage is <2.7±0.05V, the device will display the low voltage indicator LOBAT. After this indicator appears, the device can continue to work in low radiation field for 24 consecutive hours.

9.Battery and power: Two pieces of R7 batteries (AAA 1.5V alkali batteries) can work with power <2mW in the environmental background for 720 consecutive hours.

10.Temperature characteristic:<±10%   -10--±50.

11.Humidity characteristic: <±10%  95%RH (+35)

12.Outline Demention: 55(W)×92(H)×18(T).

13.Weight:<75g(<98g including batteries).

Use

1.     Battery installation and power-on reset

Remove the cover of the battery case, put R7 batteries properly into the case, and the device will beep and display DOSE and 000.0μSv.

This device has the function of power-on reset. When the device needs to return to zero, you can just re-install the batteries. Before the batteries are changed, the accumulative dose previously recorded shall be stored.

2.     Self-inspection of the device

Before measurement, the device shall undergo self-inspection. In the environmental background, turn on the working switch, and contact the display switchover button. When it displays DOSE, it records 0.1μSv for about 20 minutes and beeps shortly for one time, and the LED flashes for one time. When it displays RATE, the device displays a figure for about 36s, and repeatedly measures the background level, which is usually <0.5μSv/h. When the battery voltage is insufficient, the device will display LOBAT and the batteries shall be changed.

3.     Measurement

Press the working switch, and the device will display ON, and starts to measure. Contact the display switchover button MODE, to display RATE or DOSE respectively.

When it displays RATE, it measures dose rate in μSv/h or mSv/h. This device currently has the alarming threshold 25μSv/h. When the radiation level in the field is ≥25μSv/h, the light and sound alarming will last for 6 consecutive seconds, and the device displays ALARM. When the threshold is overrun continuously, the light and sound alarming wont last, but the device will continue to display ALARM, which wont disappear unless the radiation level drops below the threshold. When the radiation level in the field is >99.99mSv/h, it displays 99.99mSv/h only.

When it displays DOSE, the device measures accumulative dose equivalent in μSv or mSv. Recording every 0.1μSv, the device well beep shortly for one time. The device currently has an alarming threshold of 50μSv, and for rise of every 50μSv, the device will constantly alarm for 5 seconds.

4.     Device shutdown

Turn off the working switch, and the device wont display ON, and will stop measuring. After the device is off, the display switchover button still works. The accumulative dose is always stored and displayed, and the dose rate keeps 000.1μSv/h.

Precautions

When the device is not used for a long period of time, the batteries must be taken out, or the device may be damaged.