[Milsurplus] Wireless Set No.19 MK II Panel Markings

[J. Marshall Reber]

On Jan 19, 2009, at 9:36 PM, Gary Pewitt wrote:

>  I
> believe there were two basic ways to achieve a luminous dial.  One
> involved a radioactive substance giving off high energy radiation
> such as gamma rays ( alpha and beta particles won't get the job done)
> which stimulated a phosphor into giving off visible light.

Silver activated Zinc Sulphide will glow quite brightly when bombarded  
with alpha particles and has been the material most used in the past  
for radium luminous compounds; in fact, when coupled with a suitable  
photomultiplier tube is one of the most common and sensitive alpha  
detectors.  Thallium activated Sodium Iodide crystal is substituted  
for Gamma detection and certain organic crystals are used for Betas.