Model GSM-5
Survey Meter.
William B. Johnson & Associates, Inc.
3 Range Beta - Gamma Survey Meter
0 - 500, 0 - 5,000 & 0 - 50,000 CPM
0 - .2, 0 - 2 & 0 - 20 mR/hr
Serial Number 2059
Dimensions: 8" long x 6"wide (with probe) x 6" tall 9 (with handle)
Uses 3 - 1½ Volt "D" size batteries.
Includes a TGM Detectors, Inc. Type N216 - Serial Number 11673 End Window Geiger Mueller Probe
Left & Right Views
Uses a headphone with a standard ¼" jack. The Calibration pot on the top of the unit appears to be
for voltage adjustment. Has a "Battery Test" red push button. Probes attach via a BNC connector.
Left & Right Inside Views
Bottom View & Case Bottom
The 3 range scale calibration pots are visible below the battery holders.
Nameplate & Meter Face
Type N216 End Window Probe
TGM Detectors, Inc. Type N216 End Window Geiger Mueller Probe
Serial Number 11673 - Appears to be a 900 Volt Probe.
This probe does work, it has been tested with my Eberline E-140.
Handlegrip made by: Hunt-Wilde Corporation
Wm. B. Johnson & Associates, Inc. still doing business here: William B. Johnson