Atomic Bombing: How to Protect Yourself


Danger will be foretold by ingenious instruments.
7. HOW TO DETECT RADIATION

Before it kills, carbon monoxide makes you drowsy. A physical wound breaks the skin and tears the flesh; pain answers in indignation and blood points to the wound. Fire sends heat ahead of it to lick at the surface of the body, and the nerves scream their alarm of danger. But against radiation, man's body has no natural defense nor even a warning system. Radiation can do irreparable harm, yet there is no sixth sense to tell you that it is striking. You can neither see, feel, taste, smell nor touch it.

How then are victims or potential victims of radiation to know whence or when the danger comes? The answer lies in a number of ingenious instruments which science is already using, and in others, still on the drawing boards, which may someday be an essential item in your own home. If atomic attack came tomorrow however, the real answer is that victim probably would not know. They would have to be told by fast moving crews of radiation monitors using the complex instruments now available. These are man's artificial sixth, seventh and eighth senses.


Film can be used to show that radiation has struck.
Radioactivity has become synonymous in the public mind with the long-famous Geiger-Muller counter. Yet this electronic gadget is neither the oldest nor the most important of the indicators which now measure the atom's energy.

PHOTOGRAPHIC FILM

Radioactivity in general, and the X-ray in particular, were both discovered by the effect radiation has on photographic film. The chemicals in photographic emulsion are sensitive to electrically charged particles as well as to electromagnetic rays such as light. Thus film can be used to show -- after it has happened -- that radiation has struck. When the film is developed and evaluated by men trained in the art, blackening and fogging will give a rough measure of the amount of radiation which has fallen.

WILSON CLOUD CHAMBER

Radiation creates a path of electrically disturbed atoms in air through which it passes. These disturbed particles, called ions, will act as the cores for tiny droplets of water, if the air has a high enough water vapor content. One of the earliest ways found to detect radiation was in a container of superhumid air. The track of atomic particles passing through the chamber is clearly visible in thin streaks of fog. These atomic vapor trails were first observed in 1912, and have been widely used since then in the study of cosmic rays. But for measuring large amounts, the Wilson cloud chamber is not practical.

IONIZATION CHAMBERS

If ionization of air occurs between two poles bearing opposite charges of static electricity, a current will flow between the poles. As more and more ions are produced the charge across the gap will diminish. This drop in static charge may be measured, and is in turn a measure of the amount of radiation which has passed between the electrodes. An instrument of this type is known as an ionization chamber.

Simple and rugged devices built on this principle are now in use in American nuclear laboratories and atom bomb factories. Workers carry a tube similar to a fountain pen in size and shape. An even newer type is a capsule worn on the lapel. At the end of the day, these are collected and their electrical charges measured on an electrical indicator. The dose of radiation to which the worker has been exposed during the day can thus be determined. Like the strips of photographic film which the workers in AEC plants also carry, however, these detectors tell only of radiation already received.

ELECTROSCOPE


An even newer type of detection instrument is a capsule worn on the lapel.
If a super-thin piece of gold leaf or metal-coated quartz fiber is attached to one of the electrodes in the ionization chamber, it gives a visual indication of the electrical charge by bending away from the electrode. Thus, by putting a scale into the instrument, a self-reading "dosemeter" is obtained. The rate at which the fiber moves is a measure of the rate of radiation. This principle is used in another pocket detector like the fountain pen and in large instruments used to check wide areas where radioactivity is suspected.

PROPORTIONAL COUNTERS

If a battery is connected to the electrodes, the amount of current which flows through the circuit will show how fast the charge on the electrodes is being dissipated by radiation. This current is extremely small, but it can be boosted by vacuum tubes. A dial reading can be obtained which will show the rate of incoming radiation.

If certain gases are used instead of air, and high voltages are used, a single radiation produces more ionization. Pulses of current result, which can be easily measured. This is the principle of devices known as proportional counters, which are widely used for measuring contamination on hands or clothing, tables and other surfaces. They will be extremely valuable in checking residual radioactivity after an atomic bomb explosion, or in the event of radiological poisoning.

GEIGER-MULLER COUNTER

The familiar "click-click-click" of the Geiger counter is the warning rattle of the atom. Each click is a pulse of ionization caused by an individual particle or unit of radiation. Because this famed instrument can pick up even a single ray, and is easily portable, it is the instrument which will probably give the first signs that radiation is present in an atomic attack.

Actually, the Geiger counter is nothing more than a stepped-up ionization chamber. Its heart is a glass or metal tube with a wire running through it lengthwise. The tube contains gas at low pressure. High voltage is applied to establish a strong electrical field between the wire and the tube. The voltage is such that the gas is just about ready to "break down." This delicate electrical balance is broken by a ray penetrating the walls of the tube. The ray rips apart the atoms of the gas, producing free electrons. The electrons rush to the central wire and a click, or pulse, results in the listener's earphones.

Geiger counters will be the unsleeping mechanical policemen of the atomic age. They can tell when any radioactive material is in the vicinity, and give a rough indication of the strength of its radiation. But they require large amounts of power. They do not differentiate, normally, between the various types of radiation. They count beta particles with much more efficiency than gamma rays, and alpha particles only if the counter is equipped with a very delicate "window."


The Geiger counter is easily portable.
The Geiger counter will be used by monitoring crews to track down radiation, but other instruments will be necessary to tell the exact hazards to health of radioactive poisons or by-products of the bomb.

SCINTILLATION COUNTERS

When radiation strikes certain types of crystals, the structure of the crystals becomes electrically excited. The crystals fluoresce -- that is, they give off light. The amount of light released is very small, but it may be focussed on a light-sensitive electron tube and thus measured. This type of instrument, called a scintillation counter, has been used mainly in the laboratory to study radiation. But a portable counter is now being developed at Brookhaven National Laboratory which scientists think will be able to measure gamma rays in places where the radiation is so strong other instruments break down.

ATOMIC DETECTORS FOR YOU


A simple, sturdy radiation meter.
For any nation-wide program of defense against atomic weapons, tens or hundreds of thousands of detection instruments will be needed. They must be simple to operate, rugged and dependable. They must be inexpensive and widely distributed. Since the fall of 1949, Atomic Energy Commission scientists have been working at top speed to find instruments which meet these specifications.

At Oak Ridge, Tenn., AEC instrument specialists are working on a simple sturdy meter which is the size of a package of cigarettes. Based on the ionization chamber principle, it will measure the dose of radiation its owner is receiving at any time, and thus will offer ample warning if a particular area is "hot." A similar radiation meter has been invented by a father-and-son scientific team at California Institute of Technology, Drs. Charles C. Lauritsen and Thomas Lauritsen. Their device can be either cigarette-package size or small enough to be worn on the wrist like a watch. Unfortunately, neither of these devices are yet being made for general use.

Although only barest mention of its existence has been made, the Navy has a sort of "atomic dog-tag" to identify radiation victims. Like photographic film, this metal tag is treated chemically so that it will react to radiation. When a fatal dose has been received, the dog-tag shows it by turning blue. It will be of little help to a potential victim during the time radiation is at work. But for doctors working in an atomic disaster area it would be a valuable guide. They wouldn't waste time in trying to save those whose dog-tags were bright blue, but would concentrate on those whose tags were near-white or only pale blue.


A chemical detector no bigger than a book of matches.
Of potential use to the man-in-the-street is another form of chemical radiation indicator now under development at the University of California at Los Angeles. This consists of a series of tiny vials containing liquids whose colors change when radiation hits. Each of the vials or capsules changes color at a different dosage level. They may be worn hung from the neck in a plastic case the size of a packet of paper matches, or carried in the pocket in a pencil-like container. A glance would tell an individual if he receives radiation, and how much.

As is only too apparent to the officials planning atomic defense, these instruments and detectors for the home and the private citizen are all still "under development," or "being studied" or "recently invented." The atomic alarm, if such must ever be sounded, must be given by trained radiation monitors using the best equipment at hand: the Geiger counter, the proportional counter, the ionization chamber and photographic films.

Theirs will be a large part of the job of averting panic, for only by quick and accurate information on the extent of radioactivity in an attacked area will a general stampede of the uninjured to parts elsewhere be averted. Decontamination crews will be guided by "Geiger men" when the clean-up begins. Doctors will rely on their instruments in deciding whether or not a leg must be amputated because of invisible contamination in a cut on the toe. The food you eat may be "cleared" by a radiation monitor; certainly the city water you drink will be carefully checked.

These were the conditions automatically imposed on the world the day the first atomic pile began operating in a University of Chicago squash court. For with the harnessing of atomic energy came an entirely new form of possible injury to the human body -- injury which you cannot see or feel, injury which comes from invisible sources, injury which will kill you if enough is received -- kill you just as dead as a steeljacketed bullet.