Radioactivity display created for my 2014 Open day.

Radioactivity display with 12 specimens on a rotating platter passing the Geiger counter in turn This is my radioactivity display showcase. I needed a way to demonstrate these things in an interactive way without supervision.
“Continue reading” for more details and photos.It is part of a larger display case which shows some ultraviolet items.
At present it is not fully populated but I have built it using perforated board that I can use self tapping screws. This makes additions simple. Also rearrangement or repair is easy with everything being “bolted down” from the top without new holes being drilled.

The display case features are:
Easy access but (potentially) lockable.
LED strip lighting.
Front panel for switches for interactivity.
Integral fans
Shelf/storage at rear for cables, plug-packs and accessories.

The Radioactivity display itself includes a rotating platter with 12 radioactive samples that are presented to the Geiger counter:
# Andersonite. This is the rock with the green fluorescent streaks under UV. Strong gamma source from uranium salts. Count around 42,276 cpm, SD 384.
# Hot Pepper shaker. Orange Fiesta ware uranium containing glaze from the 1940’s. Gamma count around 11,436 cpm, SD 330.
# Tritium tube. Also fluorescent. Count around 391cpm, SD 21.
# Trinitite from the site of the first atomic bomb. Count around 1065 cpm, SD 58.
# Thorium from a microwave oven emitter. Gamma count around 595 cpm, SD 63.
# Polonium-210 is an alpha emitter wit a count of 346 cpm, SD 28.
# Uranium glass marble. Gamma count around 422 cpm SD 32.
# Americium-241 from a smoke detector. Strong alpha source with count 1313 cpm, SD 20.
# Zircon processed from mineral sands mined locally. Count around 273 cpm, SD 15.
# Background radiation lead shield. This is to block all the display radioactivity and give the background count of 113 cpm, SD 17.
# Potassium-40 from sodium reduced salt. Beta emitter with count around 279 cpm, SD 30.
# Radium watch face numeral. Count around 325 cpm, SD 11.
# Uranium ore. Gamma radiation with count around 22,882, SD 433.

Note that some of these have lead sheet around then. This is to reduce the pick-up from adjacent specimens, particularly when a weak source is next to a hot one.

This display also includes a 1 W UV LED. This highlights the fluorescent specimens which are andersonite and the uranium marble. The radium watch face numerals and the tritium tube are, in addition radioluminescent and are designed to “glow in the dark”.

Other projects included in the whole display but not on the platter include:
# Spinthariscope. home-made from TV screen phosphor and includes a magnifier . This can only be viewed with dark adapted eyes, so only the fluorescence under UV is visible.
# Spinthariscope viewing film with activated zinc sulphide.
# Alpha particle spark detector. Not running as it needs a HV supply.
# Cobalt-60 irradiated bottle. Apparently found in a New Hampshire barn and believed to be over 100 years old. One bottle is purple from 24 h of Co-60 irradiation presumably for testing food/drink sterilisation. The other is a control and has clear glass.
# “Amanda is Hot” from Iodine-131. Amanda has had this injected for treatment of a thyroid condition and is by far the most radioactive thing I have seen. It was noticeable when she walked into the room and the highest count was 240,000 cpm.