Neozap.com - Ex USSR ID-1 Dosimeter Review

This is a basic review of a dosimeter package produced in the 1980s in the USSR (Soviet Union). The dosimeters allow one to estimate absorbed dose (Rads) of gamma radiation up to 500 Rad. The dosimeter charger operates electrostatically (no battery required) and the dosimeters are also battery free.

This review contains:

Introduction & Origin
Package Contents
Dosimeter Charger
Dosimeters
How to Use
Reliability
Conclusions

Introduction & Origin


I purchased this unit from Soviet Army Stuff which has a large collection of what appears to be genuine ex Soviet surplus. Everything I have bought from them has been genuine.

Dosimeters are useful for estimating your absorbed radiation dose in a radioactive environment. For example, after a nuclear accident a dosimeter allows you to determine (roughly) the amount of radiation absorbed. These ID-1 Dosimeters measure radiation in Rads, which is the absorbed dose. The equivalent dose (Rem) is equal to the Rads for gamma radiation, which is what this unit measures. Rem dose helps us determine radiation effects on the body.

The modern unit for radiation is the Gray (Gy) for absorbed dose and the Sievert (Sv) for equivalent dose. Conveniently, 1 Gy is equivalent to 100 Rad and 1 Sv is equivalent to 100 Rem. So these dosimeters measure from 0 to 500 Rad (0 to 5 Gy).

Package Contents

The package as it arrives



With the lid open

ID1 Lid Open

And the package contents spread out

ID1 Package Contents

One ID-1 kit contains:

1 - Unit Logbook (In Russian, with original compliance stamps)

1 - Instruction Manual (In Russian)

1 - ID-1 Dosimeter Charger (top right of the photo)

10 - Dosimeters (Range 0-500 Rad)

1 - Box with strap (On left)

Dosimeter Charger

The dosimeter charger is the key device for this kit as it energises the dosimeters and makes them usable. This particular model operates with a piezo electric generator activated by the person charging the dosimeters. It requires no batteries!

The hole in the middle is where you insert the dosimeter, and it has a mirror which can be angled towards a strong light (so that one can see the scale in order to charge the meter).

ID1 Charger
See the section on operating the dosimeters to work out how to use it.

Dosimeters

The ID1 kit comes with ten dosimeters. One of them is shown here:

ID1 - single dosimeter

The dosimeter is a very complex piece of equipment, as is shown in this diagram below.

ID1 Dosimeter Diagram

The principle by which it operates (I think!) is related to the charged nature of ionising radiation. Basically, a high voltage potential is created inside the tube, and when a charged photon (gamma ray) enters it will progressively lower the charge. As a result, the needle will move towards the right (a higher reading) is it is only kept to the left by electrostatic repulsion. In any case, it is very clever as it does not require batteries to operate and is reasonably accurate (although I cannot test them with any source as I do not have one!).

One can read the dosimeter by placing a bright light at the white plastic end (a torch or a light bulb works fine) and then looking through the other lensed end. The scale can then be read.

How to use

The dosimeter charger is reasonably simple to use, but takes a little practice. The charger is set up with the knob on the dominant hand side of the person operating the equipment. The dosimeter is inserted into the device, and a strong light is angled via the mirror until the scale can be clearly visualised.

This photo shows the device ready for charging. A torch (top left) is angled into the mirror and into the dosimeter. The scale can be easily read.

ID1 charging

To use, you push down the dosimeter hard against the spring while vigorously turning the knob to the right. The needle will shoot off the scale to the right as the tube discharges. After about five to ten seconds of vigorous winding, the needle will come into view and start moving towards the left. If you stop winding, it will move right and off the scale again. It is tricky to work out, but is quite possible to balance and move the needle close to zero. You may get to the end of the knob's range before the device is charged. Just quickly pull the dosimeter tube up off the contacts, then turn the knob all the other way until it is reset, and start again. With practice you will be able to charge the unit in a single go.

The scale just before charging (reading 90 Rad / 0.9 Gy, presumably background radiation and passive decay since it was last calibrated decades ago)

ID1 dosimeter before charge

The scale just after charging
ID1 after charge

The device is now ready to use. It is a good idea to charge the dosimeters and see if they hold their charge over a few days before use in case they are over or under reading. See the next section for more information.

To read the dosimeter simply put a bright light at the opaque white plastic end and look through the other. To convert to Gy, divide by 100.

Reliability

I do not have a representative sample size to determine if these units are reliable after many years of storage. However, I can say that all ten of mine have charged correctly and maintained their calibration perfectly over a period of three days. I cannot see any conceivable reason why they would under-read, the worst case scenario is that they leak their charge and over read (as in, tell you that you have been exposed to more radiation, which is better than the alternative!). I am reasonably convinced that these devices will stay usable for decades more, perhaps even a hundred years as they are so simple.

Conclusions

The ID-1 Dosimeter set is very good quality surplus, and appears to be fully functional. I feel after evaluating these units that they would be tough enough to use in the event of a radiological emergency, and that they have the durability to continue being used for many weeks or months. The charging unit presents a potential single source of failure (however unlikely), but even in the event of a charger failure, one would be able to calculate radiation dose by simply subtracting previous dose from the dosimeter from the total dose, until a total dose of 200 Rad had been reached or a new charger had been found.

These units are a good deal wherever you find them and are well worth hanging on to for the future. They have no conceivable shelf life.