1950's Pocket Dosimeter with charger to detect X & Gamma rays NOT WORKING

A curio from the mid 1950's ex USA Civil Defense

You really would hope that the dosimeter stays right on zero but a very interesting piece of radiation measuring equipment from 60+ years ago that could well come in handy with current international tensions dramatically increasing in recent times.

I am offering these for the collector of such equipment, not really for practical use although they do appear to work (see the description) - they are interesting although quite cumbersome to charge/reset to zero.

Dosimeters such as these are designed to measure air ionisation caused by the presence of X rays or Gamma rays, typically generated in the radioactive decay of atomic nuclei i.e nuclear explosion.

Pocket Dosimeter(4) and charging unit

Bendix - Landsverk Dosimeter

Pocket pen style dosimeter

Model: CD V-730 & CD V-742 (a later produced replacement reading to 200 roentgens)

CD V-730 measures roentgen 0 to 20

CD V-742 measures roentgen 0 to 200

Understanding and interpreting roentgens, grays and rads is complicated (look around online for more information) but suffice to say, if your dosimeter pen is reading 200, you have big problems!

Jordan Electronics USA Charging unit

Model: CD V-750 (5b)

COSMETIC CONDITION:
All are used but in very good/excellent condition

TESTING:
The charging unit uses 1x 1.5V D cell. The charging unit uses a prehistoric switching circuit to boost this up to 220V at the external terminal.
Behind, the dosimeter terminal but inside the case is a incandescent lamp, this is the light source which shines into the dosimeter so you can read the dosimeter meter.

Push down the dosimeter lightly and the lamp shines into the dosimeter and you can read off the scale on the instrument, if any roentgen's were detected.

Push down HARD and at the same time, turn the charging unit knob, you can reset the marker inside the dosimeter to zero (a long vertical line is visible)
This procedure is cumbersome, try pushing down a tube hard onto a contact AND at the same time looking into the dosimeter to read the meter scale!

By setting the marker to zero, the dosimeter is ready for use - there is no battery in the dosimeter, it is quartz crystal based. The pointer starts from zero and if for example 20 roentgen's were detected, the pointer holds at this point until reset again. I am not sure if it shows peak values or cumulative over time.
It would probably be a good idea to move away from the area fast if anything is showing other than zero. Being exposed to high levels of X or Gamma rays is akin to being cooked from the inside out!

Full, original instructions are included with each dosimeter/charger set.

These were issued to Civil Defense authorities in USA and actually still in use until the early 2000's

These seem very simple at first glance but in fact this could be an important factor if you were in range of a nuclear blast, modern equipment is much more likely to be susceptible to being rendered useless by the nuclear blast EMP.

I can only test these to the extent of the lamp working and the charger resetting/zero functions and it must be assumed that the dosimeter's will in fact detect x or gamma ray ionisation.

4x dosimeters (1x 730 & 3x 742) with the charger and instructions

The charger box is NOT included, the photograph is of the other units I have now sold.

Suspected faulty set (charger faulty, not the dosimeters)

Dosimeters work as I have tested these with the other chargers I had but have now sold.

Lamp in the charger works

But I cannot seem to zero the dosimeter - the electronics is ancient and spare parts most likely are very difficult to find

This unit is offered ONLY for historical purposes