No 1 POST WAR CONTAMINATION DETECTION METER, 1954

Radioactivity detection unit, produced after the Second World War as a result of the Cold War period. These units were made on instruction from the government, and supplied to all Councils and Military establishments.
It was expected that in the event of a Nuclear attack, they would be ready to measure contamination levels.

This item can be demonstrated.

Your comments:

• My father bought one of these items (a Mark 2 version I believe) for me when we lived in Sheffield. As to how this came about, it's a long and strange story! This was when I was a teenager in the very early 1970's. Some electronics whizz he knew had to build a power source for it, but it worked. I carted it on holiday to Cornwall and found some radioactive minerals, but boy, was it a heavy beast to shift. After father died, we couldn't find the meter or the minerals in his house and I guess he'd disposed of them.
  .......... Neil Dickinson, Suffolk, UK, 7th of June 2016
  
  
• I'm currently attempting to restore one of these to working order, mainly by replacing the leaky paper capacitors with modern equivalents and also replacing the encapsulated metal oxide diodes with modern types. Fascinating to see the cold cathode valves in action - the neon lamp technology means that you can see the valves oscillating, so when you turn the power off and the oscillation frequency reduces before it finally stops, the valves flash slower and slower before finally going out! The are some extremely high value glass encased resistors as well - I can only measure these on a megger!
  
  The vibrator supply versions were designed to take 4 1.3V mercury cells which are somewhere between AA and AAA in size, so I've found I can fit an AA with an AAA in each side.
  .......... Robert Wood, Belper, Derby, 27th of September 2014
  
  
• We used these in Civil Defence in the 1960s. They detected beta & gamma radiation. Several different types of gm-tube could be fitted. In Civil Defence it was commonly a CV2246 or 7. Several versions of power supply could be used. The early ones had ht batteries which were obsolete later in the lifetime of the instrument. A mains power supply was also available and a later model used a power pack using AA cells.
  I actually used one following the theft of one of our test sources at a public display in, I believe, 1967. A member of the public stole a source and pocketed it. We simply stationed someone with a contamination meter at each exit and ran the probe over them on their way out. The source was recovered!
  .......... Steve Cook, Richmond/Surrey, 20th of February 2011
  
  

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