Atomic Energy Research Institute Research Articles

Atoms into Plowshares

Both the British and U.S. atomic energy projects have announced that successful means have been determined for making use of heat drawn directly from experimental nuclear reactors as an incidental source of energy. In November, according to the British Ministry of Supply, a heating system employing coils of pipes carrying water heated by a reactor was put into service to warm an eighty-room building at the Atomic Energy Research Establishment at Harwell.

Radiation measuring instruments for X-rays to cosmic rays

The paper is a review of the techniques used in the detection and measurement of very-short-wave radiations (X-rays and γ-rays) and nuclear and cosmic particles (α-particles, β-particles, protons, neutrons and mesons).The radiations and particles are classified under three headings—X-rays and γ-rays, charged particles, and uncharged particles; in each case an account is given of the more important measurable quantities (e.g. energy, W, flux of radiation, Φ, radiation dosage, r, etc.) and the physical basis of the method of measurement involved. The examples chosen to illustrate these techniques are process instruments developed at the Atomic Energy Research Establishment to provide continuous monitoring of α- and β-activities in solution. In the α-activity monitoring instrument the pulse technique is used for recording individual particles, whereas in the β-activity instrument the mean rate of ionization in an ionization chamber is measured as a direct current. Complete descriptions are given of both instruments, together with details of the performance characteristics obtained.The paper ends with a discussion of nucleonic-instrument design, and a number of aspects receive special mention, namely sourcedetector geometry, detectors in assay instruments, special problems associated with portable instruments and, lastly, materials and finishes for radioactive-contamination monitoring instruments.

Report on the British Atomic Energy Research Establishment

In the following articles, leaders of five departments at Harwell, England's laboratory for atomic energy development, describe the work of their groups. The Bulletin is indebted to H. A. C. McKay of the chemistry section for assembling these contributions. The review supplements an earlier article on the Harwell Establishment by H. W. B. Skinner in the April 1948 issue of the Bulletin. It does not deal with the progress in pile construction and atomic weapon development in Britain since 1948; the Bulletin hopes to present a report on these aspects of the program in the near future. The present review is somewhat more technical than is usual in the Bulletin; but we believe many of our readers will appreciate it. Papers describing the Norwegian and Canadian projects appeared in the May 1950 Bulletin, and the work of the French Atomic Energy Commission was reported in the Bulletin issue of October 1950.

Radiation and particle detectors in modern nucleonic instruments

The paper gives a brief review of the radiation and particle detectors used in modern nucleonic instruments and classifies the measuring systems used under four headings:(i) integrating systems;(ii) systems in which the mean current through the detector is measured, e.g. systems using current chambers, multiplying current chambers, etc.;(iii) counting systems;(iv) counting systems using an averaging circuit in the indicating unit, e.g. counting-rate meters.The paper includes a discussion of the long term stability of the radiation and particle detectors used in assay and other instruments and discusses the relative advantages and disadvantages of Geiger-Müller counters, proportional counters and scintillation counters from this point of view. Special consideration is given to the problem of industrial instrumentation where high reliabiityis the first consideration.The paper concludes with a description of a typical process control instrument developed at the Atomic Energy Research Establishment for the continuous monitoring of α-activities in solution and attention is directed to the precision of measurement possible under routine conditions.

Nuclear particle and radiation detectors. Part 2: Counters and counting systems

This is a continuation of a companion paper entitled Nuclear Particle and Radiation Detectors: Part 1-Ion Chambers and Ion-chamber Instruments, and it discusses counters and counting systems. Again the emphasis is on the detectors (i.e. the counters in this case), but some details are given of the auxiliary equipment required for a counting system, namely amplifiers, counting-rate meters, sealers and registers, and examples of a number of complete instruments are also given. Proportional, Geiger-Muller and scintillation counters are considered in detail, whilst crystal counters, secondary-emission particle detectors and thermal detectors receive only brief mention. As was the case in Part 1, the aim has been to provide sound theoretical and practical descriptions of those instruments which-in the opinion of the authors-are likely to find wide application in nuclear engineering. Illustrations of instruments and components are given, and applications are drawn wherever possible from present practice at the Atomic Energy Research Establishment.

Nuclear particle and radiation detectors. Part 1: Ion chambers and ion-chamber instruments

The paper is a review of the operating mechanisms, special properties and constructional details of the particle and radiation detectors used in modern nuclear instruments. For the most part, the detectors described are those which are in use at the Atomic Energy Research Establishment, at Harwell, and the constructional techniques are those which have been found satisfactory under laboratory conditions there, or under production conditions in British industry. The emphasis in the paper is on the detectors themselves, but brief details are given of their use in complete instruments. The characteristics of the nuclear particles (?-particles, s-particles, protons, neutrons, fission fragments, etc.) and quanta (X-rays and ?-rays) to be detected are discussed, and classification of detectors is given, the principle of detection being explained in each case and attention being called to the two different methods of use, namely as counters responding to each individual ionizing event, and as integrating elements measuring the total energy dissipation over a given interval of time. The paper also gives a detailed description of the ion chamber, the theory of its operation and the practical details of its construction. Examples of its use in radiation monitoring apparatus and in assay instruments are given. Attention is called to the use of ion chambers in process-control instrumentation and in pile-control plants. It is proposed to give a full discussion of proportional counters, Geiger-Muller counters and scintillation counters in Part 2 of the paper, to which this part (Part 1) forms an introduction.

Measurement of radioactivity in human breath.

THE breath from patients with radium or thorium in their bodies shows considerable radioactivity. Breath measurements are a useful indication of the type and amount of internal radioactive contamination. In this Laboratory, α-activity has been measured by two methods, both using apparatus supplied by the Atomic Energy Research Establishment, Harwell.

The International Oxford Conference on Nuclear Physics.

The International Nuclear Physics Conference took place in historic Oxford last September 7–13. Sponsored by the British Ministry of Supply, it was organized — and excellently so — by the British Atomic Energy Research Establishment (AERE). About 200 physicists participated; half of them came from British universities, about 30 from AERE itself, nearly as many from America, and approximately 40 from the European continent. Pontecorvo’s name was in the list of participants, but actually he was not present. There was no direct delegation from behind the Iron Curtain.

Autoradiographic evidence for the occurrence of organic iodine in the anterior lobe of the pituitary gland.

USING sodium iodide labelled with iodine-131 (supplied by the Atomic Energy Research Establishment, Harwell), we have studied by the autoradiographic technique the distribution of iodine tracer doses in the pituitary gland of the guinea pig.

The Development and Future of Nuclear Energy

The following article is the Romanes Lecture given at Oxford on June 2 by Sir John Cockcroft. Together with Dr. Walton, Cockcroft was the first to achieve artificial transmutation of atoms by particles accelerated in an electrical field. He is now Director of Britain's Atomic Energy Research Establishment at Harwell. The lecture contains one of the most authoritative and revealing discussions of the possibility of technical utilization of atomic power. The American reader will also be interested in Cockcroft's description of the history of the development of atomic energy in Britain during the early years of the war. This development, which contributed so much to the initiation and ultimate success of the atomic bomb project in America, is not familiar to most Americans, even to scientists, and is often overlooked in the discussion of whether American progress in atomic energy should be shared with Britain.

The Atomic Energy Research Establishment: Two Years Progress

The Atomic Energy Research Establishment: Two Years Progress

Extraction of the electron beam from a 30-MeV. synchrotron.

ELECTRONS of energy up to 20 MeV. have been extracted from the 30-MeV. synchrotron1 at the Atomic Energy Research Establishment with the aid of a small shunt coil carrying a pulse of current.

Correspondence

A great many radiation monitoring, and surveying instruments have been developed for use in the “hot” chemical laboratories at the Atomic Energy Research Establishment, Harwell. Some of these instruments are also likely to find application in other laboratories, and one such instrument, which may be of value in hospitals where radioactive materials are being used for therapeutic purposes is shown below.

Nuclear transmutations of carbon-13.

THIN (∼ 0.05 mgm./cm.2) deposits of carbon-13 prepared electromagnetically at the Atomic Energy Research Establishment, Harwell, have been bombarded by protons and deuterons of energy up to 1 MeV., and observations made on the (pγ)1,2, (dp)3,4, (dα)3 reactions.

Radioactive Tracers in Chemistry

THE scientific programme of this year's anniversary meeting of the Chemical Society was arranged in collaboration with the Chemistry Division of the Government's Atomic Energy Research Establishment. During March 28–30 a symposium on "The Chemistry of the Heavy Elements"and on "Radioactive Tracers "took place in Oxford, and on April 1 a discussion was held in London on "The Use of Radioactive Tracers in Chemistry". The Oxford meeting has already been reported in Nature of June 18 and 25.

Chemistry of the Heavy Elements

RECENT work on the chemistry of the heavy elements formed one main topic of a symposium, organised by the Chemistry Division of the Atomic Energy Research Establishment Harwell, on behalf of the Chemical Society and held at Rhodes House, Oxford, during March 28–30. The discovery of the transuranic elements, neptunium, plutonium, americium and curium, has demostrated that a new transition series, like that of the rare earth elements, ariving from the filling of 5f-electron levels, commences ar some stage subsequent to actinium (atomic number 89). Any attempt to trace the chemical relationships between these heavy elements, and the elements standing above them in the Periodic Table, shows how fragmentary and inexact is the existing knowledge even of the chemistry of uranium and thorium, although the former was discovered by Klaproth in 1789 and the latter by Berzelius in 1828.

The high-voltage electrostatic generator at the Atomic Energy Research Establishment

The high-voltage electrostatic generator at the Atomic Energy Research Establishment

The high-voltage electrostatic generator at the Atomic Energy Research Establishment

A 5-MV electrostatic generator of the pressurized Van de Graaff type is described. The basis of the design follows that of a recent machine built in America, and the factors leading to this design are discussed. The gas pressure chosen was up to 400 lb/in2, and the size of the pressure tank is approximately 16 ft long by 6 ft diameter. Details of the construction are given, and the results of trials are reported. The rated output of 300 μA was obtained and a maximum open-circuit voltage of just over 5 MV. This required the use of nitrogen-CCl2F2 mixture as insulating gas and the subdivision of the air-gap between the 30-in terminal and the pressure-vessel wall by the use of electrode shields. Using pure nitrogen and no shields the maximum voltage was little more than 2 MV. With positive terminal polarity, gas pressure in excess of 200 lb/in2 gave no improvement in open-circuit voltage. The voltage stability of the generator is discussed.

Disintegration of Boron-10 by Protons

THE Atomic Energy Research Establishment, Harwell, has recently produced a number of separated stable isotopes in milligram quantities. The availability of such isotopes has already enabled new nuclear reactions to be discovered, and old ones to be confirmed. In this and a later communication we wish to report on some work of this nature with boron and magnesium.

Radioactive 'Tracers' for Germany

A CONTRACT for the supply of radioactive tracers to approved research institutes in the Bizone of Germany has recently been placed with the Atomic Energy Research Establishment, Harwell, by the Joint Export-Import Agency, following the decision of the Isotope Allocation Committee of the Ministry of Supply in January last that radioactive 'tracers' produced in the Harwell Gleep could be made available for research work in Germany, The decision of the Isotope Allocation Committee was communicated to the authority responsible for the control of research in the British Zone, who immediately informed the U.S. Research Control Group. Together they approached the board of the import agency, supported by their respective public health advisers : and with the minimum of delay the Board authorized the import of radioactive tracers from Harwell into the Bizone.