Recently, I received the following email from a reader:
“In Limited Exchange Carson used a Victoreen Geiger counter. The only Victoreens I can find are of questionable quality on eBay. Do you have a suggestion for any other radiation meter that I could purchase?” I replied that I didn’t have any specific recommendations, but I explained that I chose the old yellow Civil Defense (CD) Victoreen detectors because they were quite ubiquitous during the Cold War and still are. They would be easy to source and it would not be difficult for my engineer characters to service and calibrate them. Modern devices are so much better, but they are expensive and it is difficult to find a modern equivalent to the CD meters. Why should you have radiation measuring equipment? There is no way to “gauge” radiation levels without instruments. That leaves a survivor at the mercy of local emergency services and the federal government/military to provide regional radiation levels. Many civil defense programs have been utterly gutted and focus on higher-probability, lower impact events such as tornados and floods. A nuclear war quite probably will leave you on your own for radiation readings. Individually, a personal radiation instrument can:
BLUF: Build your own (read on) or be prepared to shell out the big bucks. The selection on Amazon sucks and is nearly worthless. A really good condition and tested CD meter may be a good, affordable compromise. Basics Radiation detector is the proper term for what is often incorrectly or off-handedly called a “Geiger counter." A better term is radiation detector or radiation survey meter. These measure ionizing radiation as produced by a nuclear reaction (explosion or reactor). Electromagnetic radiation such as radio or microwaves are not a factor in this context. We will focus on the use of these detectors for post-nuclear war survival in a fallout environment particularly for those sheltering. The most dangerous phase of a fallout event is the acute (early) phase when the particles are falling down. Radiation is greatest in the first 48 hours, decreasing dramatically until the next major plateau stabilizes after about two-weeks. If local emergency authorities are intact, they will provide regional radiation readings but the continuity of emergency services or the specificity of these readings may be spotty. Individual measurement is the best way of knowing one’s radiation exposure. Anyone exposed to more than incidental global fallout would benefit from having a way to measure radiation while sheltering. An expedient Kearny Fallout Meter (KFM) can be made at home using common household items, but a purpose built detector will be more accurate, have additional features, and are not susceptible to human error in construction and calculation. Radiation detectors come in two types: survey meters and dosimeters. Survey meters are like a thermometer which is intended for an instant read and dosimeters are a measure of cumulative exposure over time like a rain gauge. Fallout produces three types of radiation: alpha, beta, and gamma. Alpha and beta radiation typically produce burns. Alpha radiation will be stopped by your skin or clothing. Beta radiation is a bit more powerful, but will not penetrate the walls of a typical home to any great degree. The danger these two present is from ingestion, so filtration of air, water, and careful cleaning of any contaminated food is the precaution for them. The most dangerous form of radiation (unless you eat fallout) is gamma radiation. This is what people are thinking of when they think of nuclear radiation. Gamma rays will penetrate all but the densest of materials easily. Eight-inches of lead or six feet of dirt is required to reduce the penetration of gamma rays to essentially negligible levels. Gamma radiation is what you are worried about. Not all devices will measure gamma radiation. A detector that only picks up alpha and/or beta radiation but not gamma will give dangerously low readings. The same problem will happen with meters that do not register high enough; .5 R/hr might not seem all that dangerous, but if that is as high as the meter will go, one could be in serious danger. The characteristic clicking sound that radiation detectors make in films are a result of ionizing events that are detected, that is, when a gamma particle passes through the detector. This causes a change in the electrical signal which is then used to produce a click through a speaker or headphones. The audible noise serves as a kind of warm/cold indicator. Count rate measurement (cpm or counts per minute) is mainly for alpha and beta radiation. A “count” doesn’t help you. A count is defined as the number of ionizing events. For survival needs, counts don’t help as they do not convert into dose rates. Dose, represented by Roentgens (R) or Sieverts (Sv), indicates how much radiation is present in a form that can be interpretated as risk to human life. A dose indicator is like a thermometer. I recommend Roentgens because a Sievert equals 100 REM (Roentgen Equivalent Man) and use R/hr because the differences between REM and RAD (Roentgen Absorbed Dose) are minimal. R/hr is also how old Civil Defense publications will read as well so it eliminates the need for conversion. Note that μSv (or uSv) is a micro-Sievert, or one-one thousandth of a micro-Sievert (mSv), one-one thousandth of a Sievert. 1 μSv is equivalent to one-ten thousandth (.0001) R and 1 mSv is one-one tenth (.1) of an R. A Sievert is the rough equivalent of 100 R. The “Geiger counter” is not what most devices are today, though they may incorporate that technology. Geiger-Mueller tubes can be saturated by high levels of radiation which may lead to an erroneous conclusion that the radiation is lower than it actually is. Radiation detectors that measure higher ranges of gamma radiation use alternate technologies such as different types of gaseous ionization chambers or scintillation counters. 
Civil Defense meters
Civil Defense (CD) yellow radiation detectors were made for various purposes. Victoreen was the most prolific manufacturer of radiation detectors in the early days of the Atomic Era. Many of these models were sold by FEMA as surplus in the late 1990s and can be commonly found for sale in various states of appearance, repair, and precision. The V-700 was intended for low-level radiation, such as an accident, contamination, or a long time after a fallout event. These were Geiger tube only designs. The V-700 is particularly susceptible to saturation of high radiation and would be worthless in a heavy fallout environment that a nearby nuclear explosion would produce. The V-700s are best suited for detecting alpha and beta radiation giving them little utility to a survivor. The V-715 is the most common model available today, followed by the V-717 and V-720. They are capable of measuring radiation between 0.1 R/h and 500 R/h using four scales (multipliers): ×0.1, ×1, ×10, and ×100. The V-717 model came with a remote probe and anti-contamination bag that could be placed outside a fallout shelter to provide the outside radiation level without leaving safety. The V-720 has a moveable shield on the bottom that can be slid open for measuring the beta radiation level as they cannot penetrate the steel case as gamma rays can. Can you use old Civil Defense meters? Yes, as long as they have been refurbished and calibrated by a competent source. For this, you will need to check the reviews and qualifications of the seller carefully. These are mechanical devices which, as long as they are in good working order, should function just fine with fresh batteries. Kearny Fallout Meter (KFM)
Noted nuclear survival author Cresson Kearny had an important caution that some meters might under-read high levels of radiation. He actually summarizes this article and his 1987 advice is frighteningly contemporary even today, 35 years later. This is why he recommends his own meter, the KFM. See also: Nuclear War Survival Skills
Neither calibration against a radiation source or tuning should be performed by an end-user who does not have specific knowledge, experience, or training doing this kind of thing. Drift of the gauge may occur over time and can be adjusted by the means of a screw inside the case. The “check source” of lightly radioactive material has well passed its half-life and cannot be assumed to be accurate. If you really expect to need to use your radiation detector, an incorrect reading may get you killed in one of the most horrible ways possible. V-715 has the least features of all the high-range CD detectors. Additionally, unmodified V-715s can have issues with losing calibration. Models with an “R” marking indicating a retrofit are much more reliable. Non-R marked V-715s should not be used, even if the seller claims that they have been rebuilt or refurbished. Non-Victoreen brand models should not be used. The V-715 includes a remote probe and a 25 foot cable that can be placed outside a shelter for remote radiation monitoring. It can also be used as a general survey meter, making it perhaps the most useful CD detector. The V-720 is considered generally reliable although the beta measurement capability may not be a factor for most users. The V-740 dosimeters are rare due to electrical leaks and failing accuracy tests. They were superseded by V-742 dosimeters and also the most common. It is necessary to buy a charger in order to use CD dosimeters. These chargers are original, special equipment and charging is not like how we would charge a phone or something similar. Should you use a 60 year old instrument? Your life may depend on this device, so why not get something that is guaranteed to be reliable and accurate? Old CD detectors don’t have return policies where you can just take them back to the Eisenhower Administration and get a new one. Modern designs include features like a digital readout, self-diagnostics, superior battery life, increased accuracy, alarm functions, and a smaller size. To answer the question, not if you can afford a modern one; affordability being the key. Wherein the problem lies with price and availability. Since the customers for these devices are industrial or government, prices are on a “quoted” basis and several hundred to thousands of dollars. Someone with the money may want to make an investment otherwise for persons of average income, a quality CD detector is probably the best purchase. Survey Meters, Dosimeters, and Alarms
Survey meter
Survey meters are generally handheld and may include remote probes. These detect surface contamination and background radiation in an instant-read method like a thermometer. The above section on the CD V-series is a good explanation of what a civilian survey meter should include. Desired features:
Do not buy an “EMF meter” or one for electromagnetic radiation; these are either ghost hunting tools or measuring things like radio or microwaves. You are measuring ionizing radiation. These tools are worthless for a nuclear war. Dosimeter A dosimeter measures personal exposure to radiation, sort of like a “sunburn detector” if there were such a thing. Damage to the body from radiation exposure is cumulative. Damage done by very small doses over time can be repaired by the body but as the dose increases, the chances of a damaged cell becoming malignant and causing cancer or other serious injury rise. These are individually worn passive devices. They do not provide an immediate reading of the radiation level making them useless to determine the radiation danger until after exposure has occurred. Some models allow for the wearer to see a real-time reading of the accumulated exposure. Only modern electronic dosimeters can provide helpful real-time information. Dosimeters are useful for knowing how much radiation you’ve been exposed to, especially in environments where conditions and radiation levels vary or are unexpected, making measurement difficult. These are most often found being used by emergency personnel or those who work around nuclear materials. Normal occupational rules prohibit exposure of more than 5R/500mSv which would prompt someone to be pulled out of danger before serious radiation injuries could occur. In a post-nuclear war environment, levels for emergency workers performing absolutely critical emergency work (i.e. rescue) in radioactive environments can be as high as 30R. Sources of contamination may vary wildly when out and about, so a live-read dosimeter is critical for knowing when they need to get to safety. For survivors, a dosimeter may be helpful but not necessary. Those sheltering will have relatively static rates of exposure and if they have a log of accurate readings individual dosage can be calculated. Dosimeters worn by radiation workers in nuclear power plants measure the whole body dose. These are usually clipped to clothing and provide a digital readout of the cumulative dosage received and may have an alarm for dangerous levels of radiation. Digital electric models typically use MOSFET transistors to measure the radiation level. The oldest dosimeter technology is the film strip badge that does not provide a reading in real time and requires the film to be developed which is where much of the cautions come from. Older CD pen-style dosimeters (pocket ionization chamber) used a quartz fiber that would take its measurement from the change in static electricity held on the fiber. These require charging before use. Electrostatic repulsion of gamma rays ionizing the gas in the fiber chamber causes the fiber to become straight, which in turn moves the gauge. This is the same principle by which the Kearny Fallout Meter operates on. Other detectors include thermoluminescence. These are composed of a crystal matrix of elements that when exposed to radiation trap the radiation and release it was light. The light released is proportional the radiation intensity which allows the exposure to be accurately calculated. Electronic devices measure the light being released while non-electric devices have strips that change color, like an instant-developing film badge. Electronic Personal Dosimeter (EPD) Modern electronic dosimeters are best and most can take instant readings of the ambient radiation level (like a survey meter) in addition to recording the cumulative dose. Some may include high radiation alarms. Preventive models are used in scientific or energy settings where radiation exposure is planned. These models are primarily administrative in nature and not designed for high radiation environments. If a nuclear worker’s dosimeter alarm sounds, it’s time to leave. Personal Emergency Radiation Detector (PERD) Emergency models are like the EPDs above, but are made for first responders and are thus more robust. PERDs are appropriate for use in much higher exposure rates, and have variable settings for different response zones (Cold, Hot, and Dangerous Zones). They are specially designed to avoid oversaturation effects. HAZMAT and nuclear response teams use these devices as their work will expose them to level of radiation where a scientist or engineer would simply evacuate away from. Affordable non-alarming PERDs are like film badges but are instantly readable. One such is the RADTriage Model50 Personal Radiation Detector is a credit card sized dosimeter that uses a color-coded matrix to provide visual indication of radiation exposure. Measurements are approximate and insensitive to lower levels of radiation. Their main advantage is their small size, robust nature, lack of batteries, and cheap cost. The above only measures medically significant doses: 50-4,000 mSv (5-400 R/.5-4 Sv), making it suitable for a nuclear fallout environment. Additionally, it boasts a 2-10 year shelf-life (extension possible in freezer) and does not require batteries or calibration. It measures cumulative doses; the more radiation it receives, the higher it will indicate until the maximum is reached. It cannot be zeroed for reuse, however. They have been used in the real world in Japan during the Fukushima nuclear disaster. 
Radiation alarms
Radiation alarms will sound if radiation is detected. These are called Personal radiation detectors (PRDs). While they look like dosimeters, they are not. These generally only indicate the presence of radioactive sources and are intended for low-levels of radiation. Their occupational use is in detection of radiological leaks, nuclear terrorism, or regulatory control by law enforcement or customs officials. Consumer devices like NukeAlert™ are simplified to alert when radiation is detected. A radiation alarm would be useful in situations where, such as after an EMP, there is no way to receive official warning of fallout arrival. Radiation alarms work by detecting the mere presence of ionizing radiation. There either is no radiation or there is—many do not provide a reading or if they do it can be quickly saturated by heavy radiation. Again, you wouldn’t buy a thermometer that only gives a reading of “yes” if you wanted to know the specific temperature. Occupational models, in fact many of them on the market, are intended for laboratory, regulatory, police, medical, or energy-sector use. Their warning levels and readouts are much too low for fallout situations other than indicating that a radiation emergency is occurring. A radiation alarm may be useful if you expect to have no other warning of fallout arrival or do not want to take routine surveys after a nuclear attack. What Should I Buy?
Virtually all of the radiation detectors and dosimeters sold on Amazon are too low for practical use in a nuclear fallout environment. You will need to source your high-rate detectors elsewhere. Frankly, most of Amazon’s “Geiger counter” products are the same Chinese crap ad infinitum. For low levels of radioactivity, they may be fine but they are not what you should be relying on after a nuclear war. The dosimeters, depending on the actual reviews and field performance, may be okay. I would buy one to test out before outfitting the family.
Low-rate survey meters and dosimeters are intended for industrial settings where any radiation above normal background rates is an emergency calling for evacuation. For the average person, these are a mere curiosity unless you are traveling to Chernobyl or Fukushima. The low-rate dosimeters may be acceptable in a well-protected shelter where the cumulative dose is expected to be lower than 5-10 R. Again, 5 R is the yearly limit for radiation workers in the United States and is a good gauge of an acceptable risk level. Note that if a product advertises a 1000 mR/hr, that isn’t much, only 1 R. The selection of radiation detectors on the market for post-fallout events is poor. The majority of the market is aimed at routine monitoring and regulatory compliance, not emergency management. There does not seem to be an easy to find, cheap analogue to the CD V-series. The dearth of nuclear war tailored devices seems to be a product of market forces than anything else. It is more profitable to make and sell devices for routine radiation work than a contingency niche product. A Kearny Fallout Meter (KFM) is affordable and effective, but it is not suited to low-levels of radiation that a post-war world years and decades down the line will present. It's also not authoritative and many ignorant people will have a hard time believing a home-build device can actually measure radiation. A combination of a KFM could be used while the radiation is high and a relatively cheap 5-10 R device used when the sheltering period is over (and the radiation is lower). If you plan on building a KFM, consider building a practice model in peacetime and purchasing a gamma check source to calibrate it yourself. Watch this video on the KFM including construction. The most cost-effective radiation detectors (survey meters, in particular) on the market are the old Civil Defense products. Take the time to research the CD Victoreen V-series meters. Don’t just buy one sight unseen off Ebay Carefully vet the seller and their refurbishment/calibration process. Read the reviews and purchase a check source to verify accuracy yourself. KI4U (www.ki4u.com) is one such well reviewed supplier. Personally, I will be building a KFM. The KFM will be used as a gross radiation monitor as I feel I only need to know about the radiation levels within its range. This will be supplemented with colorimetric dosimeters. If I was building a shelter, I would find a very good condition, calibrated and refurbished V-717 to place the probe outside the shelter. If I expected to have no warning of a fallout event (such as no news or radio warnings), I would get a radiation alarm to trigger at the first arrival of radioactive fallout. Models A brief selection of various models, mostly for informative purposes to show what’s on the market, follows. Low rate Low-rate dosimeter (5 rem) https://amzn.to/3FAYr5x Low-rate PERD 10 R https://amzn.to/3j5Fn7N 50-100 R https://amzn.to/3uUkS0x Note that most of the products sold on Amazon are for very low radiation levels and will be of very limited use in a fallout scenario. They may have utility months or years later when the radiation level has fallen dramatically. High range This one claims to server as a dosimeter of up to 9,999 Sv, but that seems too good to be true. https://amzn.to/3YpQHvD. And here’s another https://amzn.to/3Wd2OdI. This dosimeter promises up to 99,990 R or 999 Sieverts. https://amzn.to/3Py5BvH High rate dosimeter (up to 1000 R—10 R/hr metering capability) https://readymaderesources.com/product/rds-31-survey-meter-free-shipping/ High rate personal meter, 300 Rem https://www.thermofisher.com/order/catalog/product/425067675?SID=srch-srp-425067675 Survey meter, 100 R/hr https://www.thermofisher.com/order/catalog/product/4254002 Survey meter, with a pole http://radsafety.teal-server.com/product/telepole-ii Up to 100 R https://www.drct.com/dss/Technical-Associates/tbm-icm-v.html Up to 50 R https://www.flukebiomedical.com/products/radiation-measurement/radiation-safety/451b-ion-chamber-survey-meter-beta-slide Up to 9,999 R/hr https://www.berkeleynucleonics.com/dsm-500 
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Author Don ShiftDon Shift is a veteran of the Ventura County Sheriff's Office and avid fan of post-apocalyptic literature and film who has pushed a black and white for a mile or two. He is a student of disasters, history, and current events. Archives
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