Victoreen Model 300 "Proteximeter" |
|
|
|
|
| The
Proteximeter (Model 300) is a
portable beta-gamma condenser ion chamber (similar in operation to a
pocket chamber) that records an integrated exposure up to 200 mR on a
single scale. This range was chosen so that the “daily tolerance dose”
of 100mR would register a reading in the middle of the scale. |
|
|
|
|
The polyethylene chamber (see diagram to right), which is electrically connected to the grid of a V124B electrometer tube, is charged by a battery from which it is then disconnected. The charging is accomplished by turning the instrument upside down. Any subsequent ionization in the chamber due to radiation reduces the chamber’s charge and that on the electrometer tube grid. The resulting increase in the current across the tube is measured by a microameter and this current is used as an indication of the accumulated exposure. |
|
|
The
Proteximeter was developed by the Victoreen Instrument Company during WW
II -
the company Model Series Index’s assigned date for the
Proteximeter is February 1945. In
Health Physics: A Backward Glance (1980), Dale Trout described how
he used the Proteximeter towards the end of WW II for the measurement of
radiation levels around radiography units such as those used for x-raying
shell casings. During the atomic tests Able, Baker and Charlie in the
Pacific following WW II (1945 and 1946), the Proteximeter was one of the
primary instruments employed for the purpose of radiation safety. Almost
all of the instruments used at these tests were provided by the Victoreen
Company. Dale
Trout in “Health Physics:
A Backward Glance” ed.
Kathren, R.L. and Ziemer, P.L., Victoreen Model Series
Index, assigned date February 1945; AEC Radiation
Instrument Catalog, page date Advertisements and
product descriptions: Nucleonics
October 1947, p 83; Nucleonics December 1950 back cover; Campbell, D.C. Radiological Defense, Vol. IV, Armed Forces Special Weapons Project, 1950. |
|
