Copyright (C) Duncan Long 1989. All rights reserved. THE RIGHT RADIATION DETECTION EQUIPMENT By Duncan Long During a nuclear emergency, having the wrong radiation detection equipment could be as bad as having none at all. Worst, even, since it might give you the false security of thinking you were in a safe area when it was actually contaminated. If, for example, you had a high-level meter designed for nuclear war use and you tried to use it in an area contaminated by a nuclear industrial ac- cident, the results could be disastrous. For starters, the meter would probably show only a low, perhaps even fractional, reading; while this small amount of radiation exposure might not be of much consideration in a nuclear war where your goal is just to survive, in a nuclear accident, the low-level exposure is a consideration due to its effect on your long-term health. In a nuclear accident, you'd want to know EXACTLY what the radiation level is. Another problem with the nuclear war meter which you're using is that it may only detect gamma radiation; it might not pick up many of the dangerous products given off by a nuclear reactor accident. Again, this is no small consideration since isotopes which are quite dangerous to human health give off beta and alpha radiation as well as gamma. And a few give off no gamma radiation and are therefore "invisible" to your nuclear war meter. (Of the isotopes which could be encountered in an accident, cesium-137 and strontium-90 are the most dangerous since they give off ONLY beta radiation. Others like Iodine-131 and barium-140 give off gamma and beta radiation and plutonium-239 gives off gamma and alpha radiation; these would be detected by most meters.) And even in the aftermath of a nuclear war, a high-level meter might not be the best instrument for all types of work. For example, high-level meters wouldn't be so useful a year or so after the last nuclear weapons were used. Then the longer lived materials like cesium-137 and strontium-90 would be a health hazard and would be undetectable by meters which register only gamma radiation. It would be impossible to detect fallout these isotopes in food or on clothing. But an industrial, low-level meter isn't the answer for all situations either. Many low-level meters can "lock up" if exposed to the levels of radiation which might be encountered in a nuclear war; you'd get a low reading when the actual exposure was very high. Even if you were fortunate enough to have a meter that warns you when you've exceeded its limits, it would be a little disconcerting to have it beeping a warning and not be able to determine whether the radiation exposure was only a little over the meter's scale or in the "fry" range. In either case, trying to use the wrong equipment would cost you your health and maybe even your life. Because of the differences in range and type of radiation detected, few, if any, of the current generation of radiation meters are suitable for "all round" use in both a nuclear war and a nuclear accident. With this in mind, most survivalists will find they will be wanting either to purchase two or more meters, prepare for only war or only for nuclear accidents, or try to purchase a meter capable of being used in both nuclear accidents and nuclear war. You'll have to weigh the possibilities against your pocketbook. If this all isn't confusing enough, additionally, there are currently two principle types of radiation detection equipment available which can be of great use in protecting yourself from nuclear contamination. One type is the radiation meter; it gives the rate of exposure of radiation. The other type is the dosimeter; it shows the total dose of radiation it has been exposed to. It's important to not confuse total radiation exposure (or dosage) with the rate of radiation exposure. Total dosage (which is what dosimeters record) and dosage per hour (which is what most radiation meters give) can be quite different. For example, if you were taking a meter reading of 240 REMs per hour but only stayed in the area for 1 minute, your total dosage would be only 4 REM which would not represent any short-term health risks and probably would create no long-term problems. On the other hand, if you had a reading of 240 REMs on a dosimeter you'd been wearing, you'd stand a good chance of suffering from a mild case of radiation sickness. Total exposure is the most important consideration for your safety. A dosimeter is the easiest way to determine this. At the same time, a radiation meter is essential to show when you're in a dangerous area where your total exposure might become excessive. Unfortunately, radiation detection equipment isn't cheap. If you have limited funds, the place to start is the purchase of a quality meter. A meter can show where the most dangerous levels of radiation are and help you to avoid them. BUT, with only a meter, you'll have to "guestimate" your total exposure to radiation. Since your total exposure to radiation is what determines the damage to your body, it's ideal to have a dosimeter as well. Finally, purchasers should be aware that there are currently a confusing array of scales for registering the amount of radiation that is being detect- ed. Among those currently in use are milliREMs, milliRoentgens, milliSieverts, and--with equipment from Europe--milliGrays. The most common increments in the US are "Roentgens" and the "REM" (Roentgen Equivalent in Man) or "milli" (thousandths) increments of these (i.e., "Milli-Roentgen" or "mR" and "milli-REM"). In nuclear accidents or war conditions involving human beings, these two units of measurement are usually treated as being equal and interchangeable. A unit of measurement that is sometimes used in the medical and nuclear industry is the "Sievert" which is abbreviated as "Sv." The Sievert is a large unit so it is generally given as milli-sieverts (or thousandths of sieverts). One milli-REM is roughly equal to 100 milli-sieverts. Yet another unit of measure it the "Gray." Like some of the others, this unit is large and therefore normally "CentiGrays" are used. A CentiGray is equal to one Roentgen making it easy to use since it is inter- changeable with the Roentgen and REM used in most of the US. Bottom line: the CentiGray, Roentgen, REM, and 0.01 Sievert are basically equal to each other in most radiation measurements involving human beings. Now, let's take a look at what is available in the radiation meter area. Radiation Meters There are a number of good civil defense surplus meters on the market- place. But they are nearly all designed for nuclear war; they're not so ideal for nuclear accident use since most are high-range meters and they don't detect beta or alpha radiation. Many of these meters also require batteries that are becoming frustratingly hard to fine (though many large photography stores are often a good place to look). Another catch with CD meters is that it often in need of re-calibration. Since most of us aren't set up to actually test out a meter, it is wise to purchase CD equipment from someone who has recalibrated it or get a surplus meter recalibrated after you purchase it. All in all, surplus CD meters are good PROVIDED you have a source of batteries for them and have had meters recalibrated so that they're accurate. Perhaps a better route to take is to spend a little extra money and purchase one of the new, modern meters designed for nuclear war/civil defense use. Again, most of these are calibrated to read in higher 0-200 or 0-500 REM ranges which makes the low end of their scales too inaccurate for nuclear accident use (where a range in the neighborhood of 0-500 milli-REM is more ideal). But, as we'll see, a few of the newer meters can do double duty thanks to two scales of reading abilities. The state-of-the-art nuclear war survival radiation meter is the Plessey PDRM 82 which is manufactured in England. The PDRM 82 is a "smart" meter with built-in IC logic circuits to do most of the work for you. The PDRM 82 uses 3 standard "C" cells making batteries easy and cheap to purchase and stockpile for it (a set of batteries will last for 400 hours of continuous use). Controls on the unit are simple: all you have to do is turn it on or off, it does the rest. No scales to set to, no battery checks, etc., as with most other meters. On the smart side of the PDRM 82 is a microprocessor which actually checks the unit when you turn it on to be sure that it is working, checks the bat- teries while the unit is on, and warns if the unit seems to be malfunctioning. Thus, when the meter is turned on, the word "tESt" appears for the first few seconds; the word "FAIL" shows if the unit is malfunctioning, "BATT" appears if the batteries need to be replaced, and the radiation reading is shown if the unit is functioning properly. The PDRM 82 has a built-in beta source which it compares to the radiation in the environment when testing itself. Finally, if the 300 REM level of the meter is exceeded, "300" flashes on and off on the display. All of these readings show on an easily-read, liquid crystal digital display. The PDRM 82 has a specified shelf live (without batteries) of at least 20 years when stored in a dry area; you can buy it and store it away for later use without worry. As mentioned, the only downside with the PDRM 82 is that its digital reading is from 0.1 cGray/hr 300 cGray/hr (remembering that a CentiGray is equal to a REM) making the scale too high for use with most nuclear accidents (but ideal for nuclear war use). If a similar unit should be marketed for low-level use which detected both gamma and beta radiation, then it would be perfect for nuclear accident use. Cost of the PDRM 82 is $375 and the unit is currently being imported into the US exclusively by Guillory and Associates. One industrial meter which could double for either nuclear war or nuclear accident use is Dosimeter Corporation's MiniRad II 3036-2 model. This meter has two ranges of detection, one scale reads in the 0-500 mR/hr range and the other in the 0-50 R/hr range. Cost is $325. This MiniRad II is truly "pocket-sized" with a belt clip and "D" ring so that it can be worn or carried a number of ways. The unit has an internal speaker to give an audible alert as well as a gauge to give visual readings. The meter uses the common 9-volt transistor radio battery as a power source. The only drawback with the MiniRad II is that it measures only gamma and x-ray radiation; so, again, the purchaser of this unit would do will to have a second meter capable of detecting low-level beta (and perhaps alpha) radiation. In the "low-level" meter area of instruments suitable for nuclear ac- cidents, there are a number of excellent instruments since these are currently being made for the nuclear industry. One excellent industrial radiation meter is the "3007 Survey Meter" manufactured by Dosimeter Corporation. The 3007 has three low-level ranges encompassing 0-0.5 mR/hr; 0-5 mR/hr; and 0-50 mR/hr. The meter also will take Dosimeter Corporation's 3011 probe so that the meter will detect alpha, beta, or gamma radiation when the probe is in place. Cost of the 3007 meter is $290; the 3011 probe costs an additional $150. The 3007 meter uses 2 "D" cells for power. The 3007 is NOT ideal for high level use, however. Like most other industrial meters the meter might "lock up" or give inaccurate readings with VERY high exposures over 1 R/hr. Another good meter offered by Dosimeter Corporation is the 3700; this meter costs $350 with a gamma/beta probe. The 3700 has three ranges: 0-0.5 mR/hr, 0-5 mR/hr, and 0-50 mR/hr. While the 3700 doesn't detect alpha radia- tion, the chances of being in a nuclear accident where the contaminated material gives off only alpha radiation would be remote. To switch from gamma detection to gamma/beta readings, a "window" on the probe is rotated open on this probe. The 3700 uses common "D" batteries. Like other low-level meters, this unit will quit giving accurate readings or lock up when levels of radia- tion go beyond 1 R/hr. Dosimeter Corporation's Mini-Con-Rad II is a pocket-sized meter similar to the MiniRad II covered above. The Mini-Con-Rad II detects only gamma radiation with a built-in probe but--with an external probe--will detect alpha, beta, and gamma radiation in the 0-500 mR/hr range. Like the MiniRad II, the Mini-Con-- Rad II has an internal speaker, a gauge on its front, and uses a 9-volt transistor radio battery. Cost is $550. The "Radiation Alert" meter is available from Direct Safety Company for $200. This unit detects alpha, beta, and gamma radiation and has three ranges which cover 0 to 50 milliREMs per hour. The unit also boasts an internal "beeper" to give an audible signal of the radiation it is recording. Users of this meter should be cautious, however, since this meter can "lock up" at ranges above its scale. As one might suspect from the lower price tag, this meter is not quite as accurate as the other meters listed above and lacks a probe. The RDX-Radiation Monitor (also available from Direct Safety) detects beta and gamma radiation. It uses a 9-volt batter and has a switch which activates the meter only when it is held down; this makes it a little awkward in use but also keeps you from accidentally leaving the meter on and running down the battery. An internal speaker gives an audible click when radiation is de- tected; unfortunately the gauge covers only 0 to 10 milli-REMs per hour. One excellent feature with the RDX-Radiation Monitor is that it gives an audible warning if its scale has been exceeded and the meter is "locking up." Cost is $110. Yet another meter from Direct Safety is the Monitor 4 Radiation Alert pocket detector which sales for $165. This meter will detect alpha, beta, or gamma radiation and operates over three ranges to encompass 0 to 50 mR/hr. The battery-operated detector will fit into a large pocket and has an audible beeper as well as its built-in meter. Like the other two lower-priced meters, offered by Direct Safety, the Monitor 4 is not quite as accurate as the more expensive meters but would certainly be better than nothing. Whichever meter you end up with, remember remember that there is back- ground radiation in all natural environments. You SHOULD get an occasional reading on most of the above meters. That means the equipment is working; a meter not registering an occasional "jolt" from a stray gamma ray is probably not working. Only when you start getting abnormally high readings without a source of radiation or no readings at all do you have an obvious malfunction (though, of course, a meter can get out of calibration through abuse or age). A carrying strap can be very useful with most meters; just be sure you don't accidentally drop the unit because of a poorly designed or weak strap. Meters can be used inside a plastic bag when you're in a highly contaminated environment where gamma rays are your principle concern. This makes decontam- ination of the meter simple: just carefully remove the bag and discard it. Dosimeters A dosimeter is needed to give you an accurate idea of your total exposure to radiation. Modern dosimeters are about the size of a short ink pen. Internally, the sealed tube is electrostatically charged; as the unit loses its charge, it the scale reading changes. Since radiation causes the tube to discharge more quickly than normal, the scale will show when the dosimeter has been exposed to radiation (within the period of time when the unit would normally start to discharge by itself). Dosimeters have an eyepiece on one end through which you can peer at a light source to read the scale. Since a dosimeter must have an electrostatic charge to give its reading, you'll also need a dosimeter charger in order to be able to use a dosimeter. Normally, the electrostatic charge remains constant for about a month; dosi- meters in use should therefore be recharged and rezeroed at least 12 or more times a year. (Good news: one charger can be used for many, many dosimeters. Regardless of how many dosimeters you purchase, you'll only need one charger.) A dosimeter is usually worn by the person using it. The unit may be placed on a neck chain, clipped in a pocket, attached to a belt, etc. Dos- imeters should be worn at chest or belt level. This will give a better average body exposure. Placing a unit on a hat or in a boot would give low or high readings as compared to what your body is actually receiving. (In a pinch, a dosimeter might also be used for a group in a shelter. In such a case, it would be placed in a central location to give a rough idea of each person's exposure. This would only give a VERY rough idea, however. A dosimeter for each member of a group is much more ideal.) One important point: dosimeters detect ONLY gamma and X-ray radiation. In environments which are contaminated by sources of alpha or beta radiation, the dosimeter will not give any indication of actual exposure. (Alpha and beta radiation is stopped by heavy clothing and therefore not dangerous UNLESS it's ingested. Internally, the material IS dangerous since it can damage sensitive tissues in the human body.) As with radiation meters, a wide range of scales are available with dosimeters. Those designed for use by the nuclear industry or in nuclear medicine will generally have low-range scales with the units in milli-REMs or milli-Roent- gens; those designed for nuclear war use have higher ranges, usually in whole REM/Roentgen increments. Ideally, you'd again have one of each type of dosimeter since the low range scales will go "over the top" in nuclear war fallout and the high-range scales would not be precise enough for the low-level readings probable in a nuclear accident. But most of us can afford to purchase only one or the other; therefore, prudence would dictate the purchase of a high-range dosimeter since it will tell you if you're facing immediate danger from a high exposure to radiation in the 100 to 200 REM range (after which your short-term health will be at risk). In addition to a dosimeter and dosimeter charger, it is essential to have a place to keep records of readings from dosimeters. This log book doesn't need to be more than a spiral notebook; the log does need to be carefully kept. A carefully-kept log is the only way to keep track of total exposures over any period of time. During a nuclear emergency, whenever a dosimeter is to be recharged and rezeroed, the reading should be taken from it and logged. By adding up the readings, it's possible to figure total doses for the person using the dosimeter. Be sure to include the date of the reading, name of the person using the dosimeter, and the reading from the dosimeter. A few words about recharging dosimeters: some dosimeter chargers have a light built into them which allows dosimeter readings to be taken. When using such a light to obtain a reading, be careful to keep either the charger or dosimeter shielded so that the dosimeter isn't inadvertently recharged and its reading lost. When taking a reading, always point the dosimeter in the same angle each time; readings can change by several REM if a dosimeter's angle is changed from one angle to another or zeroed at one angle and then read at another. Dosimeters should be stored in a charged state so that they can be quickly used when needed. They should be recharged every month or so. If you have a group of dosimeters stored away, compare readings of them before recharging to see if they are all getting the same readings from background radiation. This will alert you to any which may tend to have higher or lower readings; these can still be used but you should note which are which. If you forget to recharge the dosimeters, so that they are in an uncharged condition when you need them, all is not lost. Just charge and zero them, allow them to stand for half an hour, and then recharge and rezeroed them. This will get them ready to go. Dosimeters are sensitive to rough handling; therefore used ones often aren't a good buy. Likewise, civil defense dosimeters are usually good but some are also junk. So be sure to purchase surplus dosimeters from a reputable dealer and then "check them out" against a good dosimeter when you're doing the monthly rezeroing of the dosimeters. The best commercial source of new dosimeters is the Dosimeter Corpora- tion. Of their various dosimeters, the 686 is probably most ideal with a reading from 0-600 REM; also good is their 638 which reads in the 0-200 REM range. Each model has a clip for attaching it to clothing and a plastic cap to protect the dosimeter from accidental recharging (when reading from a lit recharger) or damage to the contacts. The 686 is being phased out by the company and currently has a lower price tag of only $60 per dosimeter. The 638 carries a $100 price tag. If you wish to purchase a low-level dosimeter for use only during a nuclear accident, Dosimeter Corporation offers the 002 (0-200 mR), 608 (0-10 R), 611 (0-5 R), and 622 (0-20 R) for $99 each. Like meters, dosimeters can be carried in a plastic "baggie" to simplify decontamination. Dosimeter Corporation also makes the 909 Charger which is an excellent battery-operated unit which will charge nearly all dosimeters including civil defense surplus dosimeters. The 909 is small, well designed, and uses one D-cell to work. The charger has a light bulb under the charging area so so that readings can be taken without need of a light source (a consideration in a fall out shelter); a spare bulb is included with the charger. Cost for the 909 is $90. List of Companies Offering Radiation Dectection Equipment: Direct Safety Company P. O. Box 8018 Phoenix, AZ 85066 (Low-cost meters) Dosimeter Corporation Box 42377 Cincinnati, OH 45242 (Meters, dosimeters, dosimeter chargers) Guillory & Associates P.O. Box 591184 Houston, TX 77259-1184 (Plessey PDRM 82 meter) ============================================================================ Duncan Long is well-known as the author of many gun, self-sufficiency, and survival books. His firearms books are listed along with other interesting books in a free catalog available from Paladin Press, P. O. Box 1307, Boulder, CO 80306 (303) 443-7250; NUCLEAR WAR SURVIVAL is available for $14 from Long Survival, P. O. Box 163, Wamego, KS 66547. Long has also recently had a post-nuclear war sci-fi book, ANTI-GRAV UNLIMITED released from Avon Books (available from local book stores or from Avon Books, 105 Madison Ave., NY, NY 10016 for $3.75).