Model 111 and 111B Scintillator (ca. mid 1950s)

Precision Radiation Instruments' Models 111, 111B and 111C were some of the earliest commercial NaI survey meters.

The most common of these is the Model 111B (above photo). It was known as the "Deluxe Scintillator." Like most of the company’s instruments, it employed an eye-catching chromed finish. In that regard it was not too different from the automobiles of the 1950s.  The Model 111B seems to have first appeared in 1954.

For ease of operation, the “Deluxe”came with only two controls, the range and time constant switches. It employed the same six ranges used by the Model 115 “Super Scintillator”: .  The scale also indicated the percent uranium content of ore  -  in fact, it was the first instrument to employ such a “percent meter.”  While it was designed to permit aerial, motor vehicle and foot surveys, it was primarily employed as a hand-held survey meter.  The batteries were contained in a separate case that could either be attached to the surveyor’s belt or to the underside of the probe.

Detector:     1.5” x 1”NaI crystal. 

Range:         0 – 0.025, 0 – 0.05, 0 – 0.25, 0 – 0.5, 0 – 2.5 and 0 – 5 mR/h

Batteries:      four 1.5 volt flashlight batteries, two 22.5 volt batteries and two 67.5 volt

Price:       $495.00 in 1954.

The Model 111 (photo to right) was first produced in 1952. An October 1952 advertisement in Nucleonics states "Precision Radiation Instruments Takes Pride in Announcing the "Scintillator" Model 111 Portable Scintillation Counter." 

The Model 111 was known as the "standard scintillator.

Range:  0 – 0.025, 0 – 0.05, 0 – 0.25, 0 – 0.5, 0 – 2.5 and 0 – 5 mR/h

Batteries:  four 1.5 volt flashlight batteries, two 22.5 volt batteries and two 67.5 volt

Price: $495.00 in 1952.


The Model 111C (not in the ORAU collection), known as the "Custom Scintillator," became available at least as early as 1955. The following comes from a 1955 newspaper advertisement: "For those who want a super sensitive instrument. Model 111C "Custom" scintillator is twice as sensitive as the 111B. It has all the 111B features plus a 2 1/4" diameter crystal. Price only $695.00"

Most of the survey instruments produced by Precision Radiation Instruments (Los Angeles California) were intended for uranium prospecting. Nevertheless, they also produced radiation detector for civil defense and medical use. 

For some reason, maybe it was just a part of being in LA, Precision Radiation Instruments was also in the music business. While none of the PRI-owned labels (Craftsman, Tops, etc) were household names, they did produce records for some reasonably well known entertainers such as Mel Torme and Lena Horne. One PRI 33 1/3 record worth mentioning: "If the Bomb Falls," a primer on surviving a nuclear attack.


Model 111

Advertisement. October 1952 issue of Nucleonics. Page 95.

AEC. Radiation Measuring Instruments, RIB-8 (supplement 2) July 1, 1954 Page SBX-11B;

AEC Radiation Instrument Catalog No. 3. Page SBX-11B. July 1, 1952;

Atomic Radiation Detection and Measurement. Renne. 1955. Page 78.

Model 111B

Advertisement. March 1955 issue of Nucleonics. Page 96.

Precision Instruments catalog, form 1001B, 1954 copyright;

Advertisement for Uranium Prospectors Co-operative. Appeared in the April 7, 1955 issue of the Independent Record.

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Last updated: 05/10/11
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