Gram Of Radium Research Articles

The heating effects of thorium and radium product

The heating effect of radium and its decay products has been studied by many experiments, and the observed heatings compared with those calculated from the energy of the alpha, beta and gamma radiations. The most important of these measurements, as far as the α-rays are concerned, are those of Meyer and Hess, Rutherford and Robinson, and Hess. (See Meyer and Schweilder, 'Radioactivität,' 2nd edn., 1927, p. 225. et seq., for a complete list of references.) From the measurements of these authors it appeared that practically the whole of the observed heating could be accounted for by the absorption of the α-, β, and γ-rays. Fresh determinations of the quantities involved in the theoretical heating have, however, thrown doubt upon this conclusion. The chief source of uncertainty to-day in this respect is the value of the number (Z) of alpha particles emitted per second by a gram of radium. The most recent determinations of this quantity are those of Hess and Lawson, § and Geiger and Werner,|| who obtained the values 3.72 X 10 10 and 3.40 X 10 10 respectively. The former value leads to a calculated heating which agrees within 1 or 2 per cent, with the observed emission, some uncertainty arising here through the difficulty of accurately estimating the fraction of the energy of the beta and gamma rays which is absorbed in any given experimental arrangement. If, on the other hand, Geiger and Werner’s value be correct, it follows that about 10 per cent, of the observed heating must arise through some activity other than that of the known α-, β, and γ-rays.

The electric charge on the alpha-rays emitted in a second by a gram of radium

The electric charge on the alpha-rays emitted in a second by a gram of radium

LIV. The heating effect of the γ-rays of radium B and radium C

1. (1) The heating effect of the total γ-rays emitted by the quantity of radium B and radium C in equilibrium with 1 gram of radium has been found to be 8·6 calories an hour. 2. (2) Of this 0·86 ca...

XXII. The number of alpha-particles emitted by radium

After careful examination of the whole of tile experimental evidence, we are still of the opinion that the number of alpha-particles emitted per second by 1 gram of radium lies very near to 3·72. 1...

The Number ofγ-rays Emitted per Second from Radium B and C in Equilibrium with a Gram of Radium and the Number Emitted per Atom Disintegrating

Number of $\ensuremath{\gamma}$ rays emitted by RaB and RaC per atom disintegrating.--- $\ensuremath{\gamma}$-rays entering a metal produce $\ensuremath{\beta}$-ray emissions. By a $\ensuremath{\beta}$-ray emission is meant the simultaneous emission of one or more $\ensuremath{\beta}$-rays, initially in the general direction of the exciting $\ensuremath{\gamma}$-rays. Those $\ensuremath{\beta}$-ray emissions which passed through the metal window front of a counting chamber were counted, using an automatic registering device previously described. Different thicknesses of various metals were used as fronts. Corrections for scattered $\ensuremath{\gamma}$-rays and for $\ensuremath{\beta}$-rays from the walls of the chamber were determined experimentally. A standard 1.305 mg of radium was used, placed between the poles of an electromagnet. The coefficient of absorption of the $\ensuremath{\gamma}$-rays was determined from corrected counts with different thicknesses of absorbing metal placed between the source and the counting chamber but nearer the source, and the coefficient of absorption of the $\ensuremath{\beta}$-rays from a determination of the thickness of the metal cover which gave the maximum number of counts. From these coefficients and the geometrical constants, the total number of emissions which would have been produced if all the $\ensuremath{\gamma}$-rays from RaB and RaC had been absorbed in the metal was determined for Al, Cu, Sn, Pt, and Pb and found the same for all within a mean variation of \ifmmode\pm\else\textpm\fi{}3 per cent, viz. 7.28\ifmmode\times\else\texttimes\fi{}${10}^{10}$ per gm Ra per sec. equal, within experimental error, to twice 3.57\ifmmode\times\else\texttimes\fi{}${10}^{10}$ which is the number of atoms of each disintegrating per second. Evidently this proves that each radioactive transformation results in the emission of a $\ensuremath{\gamma}$-ray entity which sooner or later produces a $\ensuremath{\beta}$-ray emission from a single atom. For the hard $\ensuremath{\gamma}$-rays, capable of penetrating 1.55 cm of lead, the number of counts, corrected for absorption and scattering, came out 76 per cent of the total. Ionisation experiments, repeated by the author, give about 73 per cent, the smaller figure being due to the smaller relative ionising power of the fast $\ensuremath{\beta}$-rays. Since $\ensuremath{\gamma}$-rays are entities, the counts seem to be more significant.Coefficient of absorption of $\ensuremath{\gamma}$-rays from RaB and RaC and for secondary $\ensuremath{\beta}$-rays, determined from counts.---For all the $\ensuremath{\gamma}$-rays the values found for Al, Cu, Sn, Pt, and Pb, are 0.121, 0.38, 0.36, 1.40 and 0.78 per cm, and for the hard $\ensuremath{\gamma}$-rays 0.11, 0.32, 0.29, 0.81 and 0.47 respectively. For the $\ensuremath{\beta}$-rays in the metal in which they were produced (1) by all the $\ensuremath{\gamma}$-rays: 38.6, 160, 84.3, 374 and 200 per cm, (2) by hard $\ensuremath{\gamma}$-rays: 16.2, 58.1, 52.3, 215 and 104.

CARCINOMA OF THE LARYNX TREATED LOCALLY WITH RADIUM EMANATION

Radium and its salts continually give off a gas, created by the disintegration of the radium atoms, called emanation, which sends forth the same rays that radium does. The amount of emanation issuing from a gram of radium is called a curie, that coming from a milligram of radium, a millicurie. A millicurie is the exact equivalent in irradiating power of a milligram of radium. Radium emanation is collected from a gram, or more, of radium chlorid by means of a mercury vacuum pump which forces it into sealed glass capillary tubes, the thickness of a horsehair and ⅓ inch (8.5 mm.) long. Up to 400 millicuries of emanation, the equal of 400 mg. of raduim, may thus be condensed in one emanation tube, from 50 to 100 millicuries being, however, the usual amount. The glass emanation tubes are enclosed in little silver enameled tubes, ⅝ inch (15.8 mm.) long

The Designation of the Radium Equivalent

IN all problems that are primarily concerned with strictly radio-active phenomena the quantity λN, denoting the number of atoms transformed in a unit of time, plays a very important part. In such problems comparable amounts of different radio-elements are such as correspond to the same value of λN. There is need for a name to denote the amount of any radio-element, irrespective of family, that is thus comparable to one gram of radium. If, tentatively, we use the letter r to denote this desired name, then an r of any material may be defined as that amount of the material that will produce transformed atoms at the same rate as transformed atoms are produced by one gram of radium. The quantity r plays in radio-activity a part that is analogous to that played by the gram-molecule in physical chemistry, and the advantages to be secured by naming it are quite similar to those that were secured by the introduction of the term “gram-molecule.”

Notes and Correspondence: Madame Curie Receives Gram of Radium and Many Honors

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNotes and Correspondence: Madame Curie Receives Gram of Radium and Many HonorsCite this: Ind. Eng. Chem. 1921, 13, 6, 573Publication Date (Print):June 1, 1921Publication History Published online1 May 2002Published inissue 1 June 1921https://doi.org/10.1021/ie50138a039RIGHTS & PERMISSIONSArticle Views37Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (189 KB) Get e-Alerts

XLII. On the number of ions produced by the gamma radiation from radium

A redetermination has been made of the total number of ions which can be produced in air by the γ rays from a gramme of radium and its subsequent products. The number found is 8·4 × 1014, in close ...

Societies and Academies.

PARIS. Academy of Sciences, September 2.—M. P. Appell in the chair.—A. Lacroix: The origin of the transparent quartz of Madagascar. The hyaline quartz of Mada gascar is of complex origin, but there are only two classes of deposits furnishing the mineral in large quantities and of sufficient transparency for indus,trial purposes. One of these is in lodes of the Ampangabé type, in which the quartz is without crystalline form; the other is of hydrothermal origin, and here the quartz forms well-defined crystals.—A. Ricco: Filaments, alignements, and solar promin ences. The author confirms the view that there is a relation between the prominences and the filaments and alignements.—Jean Danysz and William Duane: The electrical charges carried by the α and β rays. From the experiments described the electrical charge carried by the α rays of one Curie of emanation in equilibrium with radium A, B, C is deduced as 9.3'8 electrostatic units per second, or nearly three times the charge found by Rutherford for radium C alone in equilibrium with one Curie of emanation. From this constant are deduced the volume of one Curie of emanation (0.595 mm.3 at 15° C.), and the volume of helium given off by one gram of radium in equilibrium with its emanation and radium A, B, and C (157 mm.3), both in good agreement with the experi,mental values.—Victor Henri and René Wurmser: Study of the law of photochemical absorption for reactions produced by the ultra-violet rays. There is a striking parallelism between the absorption curve of acetone in the ultra-violet and the chemical activity of the different rays. This reaction affords an example where the extreme ultra-violet rays are less active chemically than ultra-violet rays of greater wave,length.—Claude Verne: Solanum maglia and tuberosum. and the results of experiments on cultural bud mutations undertaken on these wild species of potato.—H. Busquet: The comparative cardiac action of the physiological extract of digitalis and other digitalis preparations.—Romuald Minkiewicz: Ciliata chromatophora, a new order of Infusoria with un usual morphology and reproduction.—C. Maltezos: Contribution to the phenomena of lightning.

Societies and Academies

LONDON. Roval Society, January 27.— Sir James Dewar: Long-period determination of the rate of production of helium from radium. In a previous communication the rate of the production of helium from 70 milligrams of radium chloride was determined by a succession of observations on the growth of pressure measured by a McLeod gauge. These observations extended over a period of about six weeks. It was thought desirable to make an experiment to determine the amount of helium resulting from this same sample of radium, after standing in a sealed bulb for an extended period. For this purpose the bulb containing the radium chloride was sealed off at the conclusion of the above-mentioned experiment of 1908 and kept for nine months. In order to measure the helium thus produced it was necessary to devise a vacuum-tight joint between the sealed radium bulb and a McLeod gauge so constructed that, after thoroughly exhausting the gauge, the drawn-out end of the radium bulb could be broken off, thus allowing the pressure of the accumulated helium in the radium bulb to be rapidly determined. The total volume of the apparatus was 320 c.c. The pressure in the radium bulb when sealed off at the conclusion of first experiment was 0.00406 mm., the partial pressure due to this amount of helium would be 0.00008 mm., which must be deducted from the observed pressure to get the true pressure due to the helium produced in the radium bulb during the period in which it remained sealed up; also the pressure in the gauge, before breaking (0.00005 mm.), must also be deducted. This gives a corrected pressure of 0.01613 mm., obtained after heating the salt, due to the helium produced from 70 milligrams of pure radium chloride during a period of 275 days, in a space the total volume of which was 320 c.c. The value of the rate in terms of cubic millimetres of helium per gram of radium per day is thus deduced as 0.463.

The Ionisation produced by an α-particle.—Part I

Using an electrical method, Prof. Rutherford and myself were recently able to determine accurately the number N of α-partieles which are expelled from a gramme of radium per second. The final value of N obtained as an average of a great number of observations was 3·4 × 10 10 α-particles per second from a gramme of radium itself, or four times this number if the radium is in equilibrium with its three α-ray products. In another paper the charge carried by an α-particle was measured by the same authors and found to correspond to 9·3 × 10 -10 E. S. unit. Since recent experiments have given conclusive evidence that an α-particle is identical with an helium atom carrying twice the ionic charge, it was necessary to take the ionic charge as 4·65 x 10 -10 E. S. unit. The values of N and e as found from the above experiments enable us to determine the number of ions which are produced by an α-particle along its whole path with a greater accuracy than hitherto. A determination of the number of ions produced by an α-particle emitted from radium itself was made in 1905 by Rutherford in the following way. The ionisation current due to a thin film of radium was measured at its minimum activity, and the total number of α-particles fired off from this film was calculated from the total charge which the α-particles carried with them. Taking the charge on an α-particle as equal to twice the ionic charge e , the number Z of ions produced by an α-particle from radium itself was found to be 1·72 × 10 5 . This number becomes 1·8 × 10 5 if for N and e the latest values, referred to above, are introduced.

The Relation between Uranium and Radium. - IV

The measurements on the growth of radium in the three uranium solutions purified by Mr. T. D. Mackenzie between three and four years ago have shown that in all the growth of radium is proceeding at a rate proportional to the square of the time within the error of measurement. The methods of testing have been improved and the ordinary error is not greater than 10-12 gram of radium. This result indicates the existence of only one long-lived intermediate product in the series between uranium and radium. The period of average life of this body, calculated on the assumption that no other intermediate bodies exist, is 18,500 years in the case of the oldest solution for which data are available over a period from the end of the third to the end of the fourth year from purification. But for the solution prepared last, over a period from the end of the second to the end of the third year, the period indicated is about half again as long as in the first experiment. Indeed, had this solution grown radium at the same rate, with reference to the square of the time, as the older solution has been doing during the past year, more radium should have been formed than the total amount now actually present. This suggests the existence of at least one new intermediate product in the series A with a period comparable to the time observations have been in progress. From a mathematical investigation of the effect of such a body on the rate of growth of radium, it is concluded that it would not, if it existed, appreciably alter the production of radium according to the square of the time over the period accurate observations have been made, even were the period of the new body as great as four years. But its existence would vitiate the calculation of the period of the direct parent of radium according to the simple formula neglecting short-lived products. Other evidence on the problem is contained in the next paper (Rays and Product of Uranium X).

An electrical method of counting the number of α-particles from radio-active substances

The total number of α-particles expelled per second from 1 gramme of radium has been estimated by Rutherford* by measuring the charge carried by the α-particles expelled from a known quantity of radium in the form of a thin film. On the assumption that each α-particle carries the ionic charge e = 3·4 x 10 -10 electrostatic unit, it was shown that 6·2 x 10 10 α-particles are expelled per second from 1 gramme of radium itself, and four times this number when in radio-active equilibrium with its three α-ray products, viz., the emanation,radium A and C. In order to reconcile the value of e / m found for the α-particle with that to be expected for the helium atom, it was later† pointed out that the α-particie should carry a charge equal to 2 e . On this assumption, the number of α-particles expelled per second per gramme of radium is reduced to one-half the first estimate. The need of a method of counting the α-particles directly without any assumption of the charge carried by each has long been felt, in order to determine the magnitude of the various radio-active quantities with a minimum amount of assumption. If the number of α-particles expelled from a definite quantity of radio-active matter could be determined by a direct method, the charge carried by each particle could be at once known by measuring the total positive charge carried by the α-particles. In this way, it should be possible to throw some light on the question whether the α-particle carries a charge e or 2 e , and thus settle the most pressing problem in radio-activity, viz., whether the α-particle is an atom of helium.

The charge and nature of the α-particle

In the previous paper, we have determined the number of α-particles expelled per second per gramme of radium by a direct counting method. Knowing this number, the charge carried by each particle can be determined by measuring the total charge carried by the α-particles expelled per second from a known quantity of radium. Since radium C was used as a source of radiation in the counting experiments, it was thought desirable to determine directly the charge carried by the α-particles expelled from this substance. In a paper some years ago,* one of us has investigated the experimental conditions necessary for an accurate determination of the total charge carried by the α-rays, and has measured the charge carried by the α-particles expelled from a thin film of radium itself. In the present experiments the same general method has been used, with certain modifications, rendered necessary by the choice of radium C as a source of α-rays. The experimental arrangement is clearly seen in fig. 1. A cylindrical glass tube HH of diameter 4 cm. is closed at the ends by ground-glass stoppers D, E. The source of radiation R is attached to the lower stopper E. The radiation from this passes into the testing chamber, which is rigidly attached to the stopper D by means of an ebonite tube F. The testing chamber consists of two parallel plates A and B about 2 mm. apart. A circular opening, 1.92 cm. in diameter, cut in the brass plate B, is covered by a sheet of thin aluminium foil. The upper chamber AC consists of a shallow brass vessel of aperture 2.5 cm., the lower surface of which is covered also with a sheet of aluminium foil.† The plate B is connected through a side glass tube to one terminal of a battery, the other pole of which is earthed. The chamber AC, which is insulated from the plate B, is connected with one pair of quadrants of a Dolezalek electrometer, the other of which is earthed. The whole apparatus is placed between the poles NS of a large electromagnet marked by the dotted lines in the figure, so that the α-rays in their passage from the source R to the testing chamber pass through a strong magnetic field.

On the scattering of the α-particles by matter

In the course of the experiments undertaken by Professor Rutherford and myself to determine accurately the number of α-particles expelled from 1 gramme of radium, our attention was directed to a notable scattering of the α-particles in passing through matter. The effect of scattering is well known in the case of β -particles. A narrow pencil of β -rays emerges after passing through a metal plate as an ill-defined beam. A similar effect, but to a much smaller extent, was known to exist also for the α-particles. Professor Rutherford* showed that the image of a narrow slit produced by the α-rays on a photographic plate broadens out when the slit was covered with a thin sheet of mica, while a well-defined image was obtained in vacuum with the uncovered slit. The question of the actual existence of the scattering effect of the α-particles has been discussed further by Kucera and Masek,† by W. H. Bragg,‡ L. Meitner,§ and E. Meyer.|| Some experiments have been made, using the scintillation method to determine the magnitude of the scattering of the α-particles in passing through matter. The apparatus used is shown in fig. 1. The main part consists of a glass tube nearly 2 metres in length and of about 4 cm. diameter. The α-particles from a strong but small source placed at R passed through a narrow slit S and produced an image of this slit on a phosphorescent screen Z, which was cemented to the end of the glass tube. The breadth of the slit was 0.9 mm., and the breadth of the geometrical image on the screen was about 2 mm., depending upon the dimensions and the distance of the source. The numbers of scintillations at different points of the screen were counted directly by means of a suitable microscope M, of 50 times magnifi­cation. The area of the screen which could be seen through the microscope was about 1 mm. 2 The number of scintillations counted varied between two or three a minute and about 80 per minute. As regards the microscope and the most convenient method to count thescintillations, the hints given by E. Regener* in his recent paper proved very useful. The microscope was mounted on a slide PP so that the scintillations produced at varying distances from the centre of the beam could be observed. The actual position of the microscope was read on a millimetre scale fixed to the slide.

Spectrum of the Radium Emanation

A FEW months ago, through the generosity of the Academy of Sciences of Vienna, one of us was loaned a radium preparation containing about 250 mg. of radium. Observations were at once begun to purify the emanation produced by it, and to determine its volume. An account of these investigations was read before the Academy of Sciences of Vienna on July 2. It was found that the maximum volume of the emanation per gram of radium was in good accord with that to be expected from calculation (about 0.6 cubic mm.), and the initial volume was about one-tenth of that determined by Ramsay and Cameron (Journ. Chem. Soc., p. 1266, 1907). In the course of this work we have had occasion to test the purity of the emanation by the spectroscope, passing an electric discharge in the capillary in which the volume was measured. We have on four different occasions during the last two months determined the spectrum of the radium emanation by visual observations, using a direct-reading Hilger spectroscope, leaving a more accurate determination of its spectrum until the measurements of the volume had been completed. We have now photographed the emanation spectrum, using a prism of 2 inches base. Pure emanation, corresponding to the equilibrium amount from 130 mg. of radium, was condensed by liquid air in an exhausted spectrum tube of about 50 cubic millimetres capacity, provided with thin platinum electrodes. Two photographs were immediately taken, one giving about thirty of the more intense lines, and the other, with much longer exposure, showing more than one hundred lines. For a comparison spectrum a helium tube was used. The colour of the discharge in the tube was bluish. Visual observations of the spectrum were made during the exposure of the photographs.

THE PENETRATING RADIATION

In the present article three distinct methods will be given to show that the penetrating radiation which produces part of the ionization in closed vessels is not due to γ rays from radium in the ground itself. It seems quite probable that the penetrating radiation must be due to radioactive products in the air and it is quite probable that the origin of these products is in the ground as Elster and Geitel's theory indicates. The first method is based upon the radium content of the various rocks as analyzed by Strutt and Eve. The highest value for the radium content of sedimentary rocks was found to be 2.92 (10)−12 grams of radium per gram of rock. The mean value found by Strutt for sedimentary rocks was 1.1 (10)−12 grams and by Eve 0.8 (10)−12 gram. The value of the radium content varies greatly with the locality, but for surface soils which are subjected to all the various kinds of weather changes the radium content is probably smaller than that found above. For instance Strutt found a radium content for chalk at the bottom of a cliff to be 0.39 (10)−12 gram and at the top of the same cliff 0.12 (10)−12 gram.

Radium and the Earth's Heat

IT has been shown by the Hon. R. J. Struct and other investigators that the materials composing the surface of the earth contain on the average about 1012 gram of radium per gram, while about one-twentieth of this amount is sufficient to account for the heat lost by the interior of the earth by conduction. Mr. Strutt has therefore suggested that the interior of the earth contains less radium per gram than the surface. It is interesting to calculate what would happen if the whole earth contained 1012 gram of radium per gram. If the specific heat of the interior of the earth is taken to be 0.1, and 1 gram of radium is supposed to generate 100 calories per hour, then it is easy to show that the temperature of the interior of the earth would rise by 105 degree C. per year if all the heat generated by the radium were used up in raising the temperature.

The penetrating radiation

In the present article three distinct methods will be given to show that the penetrating radiation which produces part of the ionization in closed vessels is not due to γ rays from radium in the ground itself. It seems quite probable that the penetrating radiation must be due to radioactive products in the air and it is quite probable that the origin of these products is in the ground as Elster and Geitel's theory indicates.The first method is based upon the radium content of the various rocks as analyzed by Strutt and Eve. The highest value for the radium content of sedimentary rocks was found to be 2.92 (10)−12 grams of radium per gram of rock. The mean value found by Strutt for sedimentary rocks was 1.1 (10)−12 grams and by Eve 0.8 (10)−12 gram. The value of the radium content varies greatly with the locality, but for surface soils which are subjected to all the various kinds of weather changes the radium content is probably smaller than that found above. For instance Strutt found a radium content for chalk at the bottom of a cliff to be 0.39 (10)−12 gram and at the top of the same cliff 0.12 (10)−12 gram.