TRW Microwave was registered with the State of California’s Department of Health with a Radiological Materials License and here is a list of their isotopes they received :
PM-147 Promethium 147 (half life 2.6234 y) which goes through Beta Decay to become Samarium 147 (half life of 1.062278031456×1011 y) which emits an alpha particle to become stable Neodymium 143
TL-204 Thallium 204, yes the deadly poison, (half life) decay7s in two ways, one is a beta particle to Lead 204 which is a long term alpha particle emitter and the other is by electron capture to Mercury 204 which then emits 2 beta particles to become radioactive Lead 204 which although is considered stable it emits an alpha particle to become Mercury 200.
CD-109 Cadmium has a half life of 462 days so the use of this isotope has to be very specific to be ordered for TRW. All of these isotopes are By Product meaning they were made in a nuclear reactor.
SR-90 Strontium 90 half life of 28.9 years is one of the isotopes that are the result of nuclear explosions or nuclear reactors. It goes through beta decay to become Yttrium 90 which has a half life of 2.662037037037 days to become Ziconium 90. Strontium 90 is one of the worst isotopes for contamination as it has a long half life and it along with Cesium 137 and Cobalt 60 are what people fear in fallout from a nuclear explosion.
Isotope | Name | Radiation | Half life |
PM- 147 | Promethium 147 | Beta | 2.6234 y |
TL- 204 | Thallium 204 | Beta, e and then 2 beta | 3.773465246068 y |
CD 109 | Cadmium 109 | e | 462 days |
Sr-90 | Strontium 90 | beta | 28.9 y |
The report below does not give amounts but a quick search reports many companies including Teledyne in Palo Alto receiving another list of isotopes and unfortunately the State of California is terrible at keeping records of radio-isotopes and their transfers. There is a whole list of sites and I will be posting those under separate articles.
Silicon Valley was Nuclear Valley before it was Silicon Valley, it was the nuclear industry with its need for precision equipment that fueled the creation of these companies.


This is TRW’s heath and Safety Manual. Note on page 16 the list of isotopes used

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