Tracerlab SU8 Pocket Dosimeter (ca. 1950-1951)

Tracerlab SU8 pocket dosimeter

The Model SU8 is a direct (self) reading pocket dosimeter manufactured by Tracerlab Inc. of Boston Massachusetts. To the best of my knowledge, it is the first dosimeter produced by Tracerlab.

As you can see from the photograph, the extended stainless steel end makes it look like just a fountain pen. The company’s photographs of the SU-8 usually showed it alongside a real fountain pen. After all, the dosimeter would often be worn inside a shirt pocket right next to a pen or two. In my opinion, this is the best looking dosimeter ever produced.

Tracerlab SU8 pocket dosimeter

The SU8 is somewhat unusual in a couple of respects. First, it is particularly sensitive: it reads from 0-100 mR. Second, and this is what distinguishes it from most dosimeters, the charging contact is activated magnetically. When the SU8 is in the vertical position, the external charging contact is connected to the dosimeter fiber via an internal pin that is raised by a magnet in the dosimeter charger. In any other position, three small balls inside the unit prevent the pin from accidentally making contact with the fiber. This design, which originated with Francis Shonka, reduced the possibility of accidental discharge. It did however require the use of a special charger, the SU9.

Range: 0-100 mR (SU-8H has a 0-200 mR range)

Size: 4.25” long and 0.5” in diameter

Price: $39.50 in 1951

Donated by Ron Kathren.


  • Nucleonics March 1953 p57.
  • AEC Radiation Instrument Catalog, page date May 1, 1950.
  • AEC Radiation Measuring Instruments, RIB-8 (supplement 2) July 1, 1954.
  • Tracerlog No. 33, March 1951.