Record Details
Enlarging radiation survey read-outs for large audience viewing
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Enlarging radiation survey read-outs for large audience viewing |
| Names |
Aaserude, Robert Arnold
(creator) Trout, E. Dale (advisor) |
| Date Issued | 1965-08-12 (iso8601) |
| Note | Graduation date: 1966 |
| Abstract | A method is presented for enlarging read-outs from a Victoreen Model 575 Radocon, an ionization chamber type of radiation survey instrument. The read-out enlargement is accomplished by taking the signal across the Radocon indicating meter, amplifying it, and using the amplified signal to drive a projection meter. The face and back of the projection meter are made of transparent Lucite so that the meter may be placed in a standard lantern slide projector, and an enlarged image of the meter scale and index pointer projected on a screen or wall. A field-effect transistor used as a source-follower provides the amplifier with an input impedance of over 100 megohms so that the current flowing through the Radocon indicating meter is not reduced when the amplifier input is connected in parallel with it. An emitter-coupled differential amplifier takes its input from the source of the field-effect transistor; its output drives the projection meter. The differential amplifier provides the gain necessary to accurately drive the projection meter. Through the property of common-mode rejection, the drift in output due to variations in temperature is reduced. In operation, the input of the amplifier is connected in parallel with the Radocon indicating meter. The polarity is arranged so that the voltage on the gate of the field-effect transistor goes from zero to plus 0.1 volt as the Radocon indicating meter goes from zero to full scale. The amplified signal appears as a voltage difference between the collectors of the two transistors in the differential amplifier. The projection meter, placed between the collectors, provides the final read-out. This method of read-out enlargement makes it possible to accurately display radiation measurements to a large audience. The read-out enlarger, used with the Radocon Model 575, can be used in a large classroom to demonstrate various physical laws which involve changes in radiation intensity. The same method may also be used to enlarge read-outs from other types of instruments. An accurate enlargement may be obtained without altering the circuit of the instrument or affecting its read-out. |
| Genre | Thesis/Dissertation |
| Topic | Radioactivity -- Instruments |
| Identifier | http://hdl.handle.net/1957/47796 |
