Beta ray

“ It is one of the most firmly established laws of nature that energy is always conserved. One would therefore expect that the energy of a beta ray would be exactly equal to the difference between the energy of the nucleus before the beta decay and the energy of the nucleus after the beta decay. As a matter of fact the energy of a beta ray is found never to be as great as this amount. Frequently it is much less. Some of the energy has apparently disappeared and the suspicion has been 35 voiced that energy may not be conserved after all. ”

“ The reader will recall that the spacing of the ionization depends only on the charge and the speed of the ionizing particle. The ionizing particle from the Sr90 is an energetic beta ray, which has a charge of one and a speed close to that of light. A large part of the background radiation which reaches our bones comes from the cosmic rays. The main portion of the cosmic rays is due to the mesons. The meson, like the beta ray, has a unit charge and a speed close to that of light. The two particles may therefore be expected to produce identical biological effects. ”

“ A radioactive atom can transform itself in two ways: it can expel from itself an atom of helium, which, thrown off at an enormous speed and with a positive charge, constitutes an Alpha ray. Or, instead, it can detach from its structure a much smaller fragment, one of those electrons to which we have become accustomed in modern physics, and whose mass, 1800 times smaller than that of an atom of hydrogen when its speed is moderate, grows excessively when its speed approaches that of light. These electrons, which carry a negative charge, form the Beta rays. ”

“ What one usually knows instead, is the roentgen dosage to a piece of tissue, which consists of many cells. If the charged particles inducing the ionization are electrons (as they are when the primary radiation is a beta ray or a gamma ray) , the ionization will be distributed more or less uniformly among the cells in the affected neighborhood. If the charged particle is heavy—a proton or an alpha ray—the density of ionization which it produces is much greater, so that some cells receive a good many more ion pairs, while others nearby may receive none. ”

“ This procedure was useful but it was hard to make an accurate analysis of low concentrations of heavy water.
More recently, however, tritium (3H) (radioactive hydrogen) has been produced in abundance. Its oxide, tritiated water (3H2O) , is chemically almost the same as ordinary water, but physically it may be distinguished by the beta rays given off by the tritium. This very soft (low-energy) beta ray requires the use of special counting equipment, either a windowless flow-gas counter or a liquid scintillator, but with the proper techniques accurate measurement is possible. ”

“ Beta rays, nature of, 246; accompanied by gamma rays, 247;
production of, by gamma rays, 247; as ionising agents, 249.
Biotite, containing haloes, 223; pleochroism of, 235; intensified
pleochroism in halo, 235.
Body and mind, as manifestations of progressiveness of the
organism, 86.
Boltwood, age of minerals by lead ratio, 20.
Bose, theory of latent image, 203.
Bragg and Kleeman, on path of the alpha ray, 215; stopping power,
219; laws affecting ionisation by alpha rays, 220; curve of
ionisation and structure of the halo, 232. ”

“ Radium decomposes with the emission of two sorts of rays called the alpha rays and the beta rays. The alpha rays are neither more nor less than atoms of the gas helium, long since known to exist in the sum by its spectrum, and more recently detected in a uranium ore. The beta particles are identical with the electrons which form the cathode rays. ”

“ But that, Leonard, will be necessary for a few hours only, until we are well out beyond the stars.”
He said it quite quietly. But I gasped. “Beyond the stars . . . in a few hours?”
“Yes,” he said. “In our case, differing from my experiment with the model, we carry the Elton Beta ray, the ‘red ray,’ with us. The gravity principle we use only at the start, to avoid a possible collision. With the red ray preceding us, we will follow it. Ultimately at four hundred thousand miles a second. ”

“ This navigation of space was clear enough. All my life scientists had been discussing it. We were moving now at a velocity of some twelve thousand miles an hour. But what was that? Less than the crawling of an ant using the equator of the earth as a race track! Twelve thousand miles an hour—or twelve billion—would get us nowhere among the distant stars in a lifetime!
Dr. Weatherby answered my spoken question: “We are only very little larger than when we started, Leonard. An infinitesimal fraction, for our velocity is nothing as yet. I’ll use the Elton Beta ray once we get farther out.” ”

“ Man observed these rays proceeding from radium, but, not knowing the cause of them, he called them gamma rays. We can, of course, produce radiographs when these rays fall upon photographic plates. Indeed, some of my fellow-electrons, when escaping from radium, have produced rays sufficient to penetrate a six-inch boulder and affect a photographic plate lying beneath the boulder. In time man recognised these rays as X-rays.
Man did not find only these rays—he discovered that electrons were escaping, but before he had recognised what we were, he had named us beta rays. ”

“ Its compounds color flames carmine and give a characteristic spectrum. It resembles barium chemically. Radium preparations are remarkable for maintaining themselves at a higher temperature than their surroundings, and for their radiations, which are of three kinds: alpha rays, beta rays, and gamma rays (see these terms) . By reason of these rays they ionize gases, affect photographic plates, cause sores on the skin, and produce many other striking effects. ”

“ The flash of light produced when an individual ionizing particle or ray strikes a sodium-iodide crystal is noted by a photoelectric cell. The intensity of the flash is a measure of the energy of the radiation, so the voltage of the output of the photomultiplier tube is a measure of the wavelength of the original gamma ray. The scintillation counter can observe up to a million counts per minute and discriminate sharply between gamma rays of different energies. With proper windows it can be used for alpha or beta counts as well. ”

“ Those falling in the other direction are the beta rays. The gamma rays seem to flow straight.”
“Then it is the alpha rays with which we are concerned mostly now?” I queried, looking up.
“Exactly. That is why, when radium is unprotected or insufficiently protected and comes too near, it is destructive of healthy cells, produces burns, sores, which are most difficult to heal. It is with the explanation of such sores that we must deal.”
It was growing late. We had waited patiently now for some time. Kennedy had evidently reserved this explanation, knowing we should have to wait. ”

“ Directed upon plates of aluminium he finds its gamma rays to be 100 times more penetrating than its beta rays, and beta rays 100 times more penetrating than its alpha rays. Each radiation has qualities as distinct as those of an ordinary chemical element. Beta rays behave in all respects like cathode rays, so that here a bridge is discerned betwixt the qualities of radium and the long familiar phenomena of the Crookes tube.
The substance ranking next in radio-activity to radium is thorium. Professor Rutherford has observed it throwing off a substance he calls Thorium X ”

“ X rays and gamma rays are therefore examples of ionizing radiation.
Radiations may consist of flying particles, too, and if these carry sufficient energy they are also ionizing in character. Examples are cosmic rays, alpha rays, and beta rays. Cosmic rays are streams of positively charged nuclei, predominantly those of the element hydrogen. Alpha rays are streams of positively charged helium nuclei. Beta rays are streams of negatively charged electrons. The individual particles contained in these rays may be referred to as cosmic particles, alpha particles, and beta particles, respectively. ”

“ Some types of radiation—those made up of comparatively large particles, for instance—are more effective in producing ions and bring about molecular changes with greater ease than do electromagnetic radiations delivering equal energy to the body. Thus if 1 rad of alpha particles is absorbed by the body, 10 to 20 times as much biological effect is produced as there would be in the absorption of 1 rad of X rays, gamma rays, or beta particles. ”

“ Beta particles (electrons) have a moderate penetrating power, therefore they produce useful therapeutic results in the vicinity of their release, and they can be detected by sensitive counting devices. Gamma rays are highly energetic, and they can be readily detected by counters—radiation measurement devices—used outside the body. ”

“ Synthetic sunlight produced by him with an electric arc light of his own invention proved as good as natural sunlight, and could be better regulated to the patient’s endurance. He used two distinct kinds of light-rays, the short ultra-violet rays for nerve nutrition, and the long red and infra-red rays for muscle treatment. Red rays, as can be seen when the hand is held up against the sunlight, penetrate the flesh to a considerable extent, and can therefore stimulate the sleeping muscle. ”

“ Arc lights throwing powerful ultra-violet rays are being installed in beauty shops and hotels, and patrons are given opportunity to bathe their bodies in this brilliance. These rays are being billed as more potent than sun baths, and citizens who have small chance to see the orb of day get their sunshine and their medicine at one swoop.”
Two Indian scientists, S. S. Bhatnagar and R. B. Lal, of the University of the Punjab, Lahore, discovered in 1925 that germs grow faster when exposed to “polarized” light than to ordinary light. ”

“ Beta particles are very light, charged particles that are found primarily in fallout radiation. These particles can travel a short distance in tissue; if large quantities are involved, they can produce damage to the basal stratum of the skin. ”

“ Liquid scintillation solutions share with other scintillating materials the property of converting into visible light the energy deposited in them by ionizing radiation. In theory, if a sample of a beta emitter is dissolved in a liquid scintillator solution, every beta particle emitted will be absorbed completely because the range of penetration of beta particles in liquids is quite short (ranging from 0.008 millimicron for 3H to 7.9 millimicrons for 32P in a medium of unit density) . ”

“ The penetrating power (“hardness”) of these rays appears to be determined solely by the nature of the elements in the emitting substance. The velocity of the cathodic (or secondary Roentgen) rays seems to be quite independent of the matter exposed to the primary rays, but increases as the hardness (penetrating power) of the primary Roentgen rays increases.
The character of the emitted rays, in brief, appears to be quite unaffected by the chemical or physical condition of the element. Red-hot iron, for example, exhibits the same characteristic Roentgen radiation as iron at room temperature. ”

“ Like a child which hides behind a wooden door to shield itself from the bullets of a machine gun, our young radiologists believe they are safe when they have donned their gloves and examine their patients behind a sheet of lead glass. But, unfortunately, these enable them only to avoid those superficial skin affections caused by the most absorbable rays of the spectrum. ”

“ I was thinking rather of the dangers than of the beneficence of radium just now, but Kennedy continued.
“It has cured many malignant growths that seemed hopeless, brought back destroyed cells, exercised good effects in diseases of the liver and intestines and even the baffling diseases of the arteries. The reason why harm, at first, as well as good came, is now understood. Radium emits, as I told you before, three kinds of rays, the alpha, beta, and gamma rays, each with different properties. The emanation is another matter. ”

“ Lazarus-Barlow, Professor of Experimental Pathology in the University of London, concludes that even though heat-rays may also play some part in curative processes, “experience of the treatment of wounds by sunlight in France during the World War indicated that a degree of benefit arises from exposure to sunlight which cannot be attributable to warmth and ultra-violet rays. ”

“ That both the compound rays of ordinary sunlight and ultra-violet rays (“artificial sunlight”) are highly effective in the treatment of a number of complaints is now well known. They are both in general use for the external treatment of rickets, tuberculosis, and a number of other diseases. Light-rays are also applied to hasten the healing of wounds. ”

“ Highly important as are the phenomena of Radioactivity from the physical, chemical, medical, and philosophic points of view, they are hardly comparable in their relations to the affairs of our everyday life to the Roentgen or X-rays, and to the invisible violet or ultra-violet rays. The X-rays are utilized today in hundreds of practical ways, and are vastly important also in surgery, medicine, dentistry, and in biological investigations. ”

“ The only satisfactory mental picture which the facts allow us to form, at present, of the emission of β-rays from radium compounds is that which represents these rays as streams of electrons, that is, particles, each about a thousand times lighter than an atom of hydrogen, each carrying an electric charge, and moving at the rate of about 180,000 miles per second, that is, nearly as rapidly as light. ”