CD V-700 GM Survey Meters (ca. 1954-1964)
The Model CD V-700 is a “highly sensitive” low-range survey meter that employs a side window GM detector. According to the Handbook for Radiological Monitors, it “can be used (1) in long term clean-up and decontamination operations, (2) for personnel monitoring, and (3) for indicating the degree of radioactive contamination in food and water.” Nevertheless, it was primarily viewed as a training instrument because it was too sensitive to be of much use in the aftermath of a thermonuclear war.
The first CD V-700, referred to by the OCDM as the Model 1, was the Nuclear Measurements Corporation Model GS-3CD (see photos above and to right). This can be considered the granddaddy of civil defense survey meters.
Quoting a February 1955 product description of the NMC instrument: "Model GS-3CD exceeds CDV-700 specifications in size, weight (4 3/4 lb), and ruggedness. Detects betas and gammas in three ranges 0-0.5, 0-5, and 0-50 mr/hr."
With one exception, the case bottoms I have seen of the Model 1 did not have the circular civil defense sticker seen on the Model 2 (below right). The sticker on that one exception was not centered and appears to have been added well after the manufacturing date.
There seems to be a very early reference to a Model 700 in an Anton Electronics advertisement in the May 1956 issue of Nucleonics. The ad has a photo of a survey meter identified as a "700 Survey Meter." It has no visible civil defense markings on it, but it is very similar in appearance to the Victoreen Model 2 shown in the photo below right. Strange.
Visually, the Victoreen Model 2 is identical to the NMC CD V-700 Model 1. In fact, the battery holder inside the Victoreen meter is stamped Nuclear Measurement Corporation (see below)! It would seem that Victoreen must have purchased the meters from NMC and put their own name on them.
The detector probe (chrome-plated brass) incorporates a beta shield that can be used to distinguish between gamma and beta radiation. A headphone jack is located on the top of the instrument case. The electronics of the Victoreen Model 2 (to right) and the International Pump Model 3 (below right), employed vacuum tubes. Later versions were transistorized e.g., the Model 6A and 6B.
The following statement comes from a June 1959 revision of a 1955 Civil Defense Technical Bulletin: "To provide a capability for meeting the various requirements of civil defense operations and training, OCDM has developed the following types of instruments:... "A highly sensitive dose-rate survey instrument that can discriminate between beta and gamma radiation, for long-term cleanup and decontamination operations and for training programs, where low radiation dose rates will be encountered (CD V-700)."
Both the Model 3 and the Model 4 are referred to in an OCDM Advisory Bulletin dated January 8, 1959. As such, these models date from 1958 or earlier.
The model 4 had the reputation of being the worst of the CD V-700s. The case was made of plastic rather than metal like those of the other CD V-700 models. Among other things, the latches were easily broken. They have been repaired in the example shown to the right. See what the latch should look like and how the repair is made.
The manufacturer, Universal Atomics Corp., also made a commercial version of this instrument, the UAC 700.
In September 1985, FEMA sent a notification to the maintenance and calibration facilities indicating that Models 1 - 4 of the CD V-700 were obsolete.
The accompanying photo in the bulletin is the Anton Model 5.
Based on the date of the operating manual for the Model 5, this instrument was first manufactured in 1959.
In 1961, Nicholas Anton (founder of Anton Electronic Laboratories that had been taken over by Lionel in 1960) started the EON Corporation and began producing a commercial version of this instrument, the PSM 700.
The photo to the right shows a CD V-700 Model 6B manufactured by Lionel, the same folks that make toy trains. Learn more about Lionel's entry into the nuclear business.
Range: 0-0.5, 0-5.0, 0-50 mR/h
Note that typical GM meters of the time only measured up to 20 mR/hr. I was told that compromises were made in the design of the CD V-700 to extend the range to 50 mR/hr.
Response time: 95% of final reading within 8 seconds
Operating voltage: 1000 volts
Temperature: -10 to +125 degrees F
Check source: Instrument should read ca. 2 mR/h with beta shield open
Batteries and GM Tubes (as specified in maintenance manuals):
- Model 1 Nuclear Measurements Corp: two 1 1/2-volt D cells and three 45 V B cells
- Model 2 (661) Victoreen: two 1 1/2 V D cells and three 45 V B cells; RCL Mark 1 Model 22 GM tube
- Model 3 International Pump: two 1 1/2 V D cells and three 45 V B cells; Amperex Model 85NB GM tube
- Model 3 Chatham Electronics: two 1 1/2 V D cells and three 45 V B cells
- Model 4 Universal Atomics: five 1 1/2 V D cells; Anton Electronics Model 114 GM tube
- Model 5 Anton: five 1 1/2 V D cells; Anton Model 6993 GM tube
- Model 6 Anton: five 1 1/2V D cells; Anton Model 6993 GM tube
- Model 6 Victoreen: four 1 1/2 V D cells; Model 6993 (no manufacturer specified in manual)
- Model 6A Victoreen: four 1 1/2 V D cells; Model 6993 (no manufacturer specified in manual)
- Model 6B Victoreen: four 1 1/2 V D cells; Victoreen Model 6993 GM tube
- Model 6B Lionel: two 1 1/2 V D cells; Lionel Model 6993 GM tube
- Model 6B Electro-Neutronics: four 1 1/2 V D cells; Lionel and EON Model 6993 GM tubes
The photograph below shows various examples of the GM tubes used in the CD V-700. From left to right, an Eon Model 6993, a Victoreen Model OCDD-103, a Lionel Model 6993/114, an Amperex Model 85NB- 6980, a Victoreen Model 6993, and an Anton Electronics 114/6993.
The following photos show two GM tubes produced by Radiation Counter Laboratories that were used in CD V-700s. The first is a glass-walled RCL tube dated 10-55. It came from a Victoreen CD V-700 Model 2. The Model 1 came with the same tube. The second is a metal walled Model 10317/6993 RCL tube.
Estimated Dates of First Production:
- Model 1 1954, 1955
- Model 2 1956
- Model 3 1957
- Model 4 1957, 1958
- Model 5 1959
- Model 6 1960
- Model 6A ca. 1961
- Model 6B 1962
Approximate Cumulative Procurement, Inventory and Distribution of CD V-700s*
|Through FY 1956||5,275|
*The numbers in the above table should be considered approximate. I compiled them from data in the Annual Statistical Reports of the OCDM, OCD and DCPA. By "procured," I mean delivered by the manufacturer to the OCDM, OCD or DCPA. "Inventoried" means stored in a Federal (rather than state) warehouse available for distribution. "Distributed" means sent to the end user. The latter primarily means the states, but also various federal agencies and even foreign governments. The number of procured instruments may be greater than the combined number of inventoried and distributed instruments for a variety of reasons: some may have been sent back to the manufacturer, some may have been disposed of, the numbers might be incorrect, etc.
Donated by the Northern Ohio Chapter of the Health Physics Society courtesy of John Wills, Federal Emergency Management Agency courtesy of Carl Siebentritt, the State of Wisconsin courtesy of Michael Mack, and my good friend William L. Bashaw III. Thanks also to Don Lanzrath for his help in obtaining the NMC GS-3CD.
- Anton Electronics Laboratories Inc. advertisement. Nucleonics, May 1956, page 131.
- Product description (Survey Meter). Nucleonics February, 1955. p. 88.
- Office of Civil and Defense Mobilization. Radiological Instruments for Civil Defense. Technical Bulletin TB-11-20. September 1955 (Revised June 1959).
- Office of Civil and Defense Mobilization. Interim Procedures for Maintenance of Radiological Instruments. Advisory Bulletin No. 229. January 8, 1959.
- FEMA, Radiological Instruments: An Essential Resource for National Preparedness. CPG 3-1/September 1986.
- Victoreen Instruction Manual for CD V-700 Model 2 (Vicco 661).
- International Pump Instruction and Maintenance Manual for CD V-700 Model 3.
- Universal Atomics Instruction and Maintenance Manual for CD V-700 Model 4.
- Anton Instruction and Maintenance Manual for CD V-700 Model 5; 1959-1960.
- Victoreen Instruction and Maintenance Manual for CD V-700 Model 6 and Model 6A; 1961.
- Lionel Instruction and Maintenance Manual for CD V-700 Model 6B; 1962-1963.
- Victoreen Instruction and Maintenance Manual for CD V-700 Model 6B; 1962.
- Electro-Neutronics Instruction and Maintenance Manual for CD V-700 Model 6B; 1963-1964.