Keep these tips in mind to get an accurate reading from your Kearny Fallout Meter:
- A KFM is a simple electroscope fallout meter with which fallout radiation can be measured accurately.
- To use a KFM, an electrostatic charge must first be placed on its two separate aluminum-foil leaves.
- These leaves are insulated by being suspended separately on clean, dry insulating threads.
- To take accurate readings, the air inside a KFM must be kept very dry by means of drying agents such as dehydrated gypsum . . .or silica gel. . . Pieces of drying agent are placed on the bottom of the ionization chamber (the housing can) of a KFM.
- An electrostatic charge is transferred from a homemade electrostatic charging device to the two aluminum-foil leaves of a KFM by means of its charging-wire. The charging-wire extends out through the transparent plastic cover of the KFM.
- When the two KFM leaves are charged electrostatically, their like charges (both positive or both negative) cause them to be forced apart.
- When fallout gamma radiation (that is similar to X rays but more energetic) strikes the air inside the ionization chamber of a KFM, it produces charged ions in this enclosed air. These charged ions cause part or all of the electrostatic charge on the aluminum-foil leaves to be discharged.
- As a result of losing charge, the two KFM leaves move closer together. (Source)
The first thing you need to do is print off the PDF instructions from the Virginia Tech website and/or the Google Docs page. I found that the V-Tech instructions were more detailed but the Google Docs instructions were more understandable. They must be printed to scale for your meter to be accurate. Once you’ve printed off the instructions, gather your materials and read through the directions in their entirety. The following 5-part video series takes you through the entire process, step by step, and will likely answer any questions you might have after reading the instructions. The last video also shows you how to use the meter once you have constructed it.