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New facilities and plans for high voltage electron microscopy SESSION CHAIRMAN:
H. P. J E N E R I C K , National Institute of General Medical Sciences, Bethesda, Maryland, U.S.A.
The Swedish IN~lkV d ~ o n mlcroscol~, ROLAND KIESSLING, Swedish Institutefor Metal Research, Stockholm, Sweden. 3M'V electron microscope , G. DUPOUY and F. PERRIER, Lab. d'Optique Electronique du C.N.R.S., Toulouse, France. The Plklltps EXM-10tm ~ voltage electron microscope, K. J. VAN OOSTRUM, Philips Research Laboratories, Eindhoven, Netherlands.
High voltage electron microscopy t a ~
at the University oF V ~
R. GEISS, K. R. LAWLESS, H. G. F. WILSDORF, Charlottesville, Virginia, U.S.A.
High voltage electron microscopy at the University oF Calitornla at Berkeley, G. THOMAS, Berkeley, California, U.S.A. Development program for a MOkV ~ r e ~ microscope, R. E. WORSHAM, J. E. MANN, E. G. RICHARDSON, Jr., G. G. SLAUGHTER, N. F. ZIEGLER, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. Plans t o t new h l s h voltase ~ n microscopy t a d l t t l e s H. FUJITA, Osaka University, Osaka, Japan. P. R. SWANN, Imperial College, London, U.K. D. F. GIBBONS, Case-Western Reserve Unitmrsity, Cleveland, Ohio, U.S.A. G. K. WILLIAMSON, C.E.G.B., Berkeley, U.K. P. B. HIRSCH, University of Oxford, U.K. S. M. OHR, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. M.J. MAKIN, A.E.R.E., Harwell, U.K. K. F. HALE, National Physical Laboratory, Teddington, U.K. Less than 10 electron microscopes with accelerating potentials of 500kV or more were known to be operating in France, England, Japan, the Soviet Union, and the United States when the programme for the nvEu conference was drawn up. This session was arranged to bring the audience up to date on the status of the rapidly increasing number of HVEM installations planned for various laboratories throughout the world. It turned out that several of the new instruments were actually put into initial operation just prior to the meeting so that some preliminary results were also presented. It appears that the number of microscopes in the world operating in the range of 500kV to 3000kV will double in the period from spring 1969 to summer of 1970 to a total of more than 20. Surprisingly, the majority of this interest is in the field of materials research (i.e. ceramics, metals, and polymers), with only one instrument devoted primarily to the examination of biological molecules. R. KIESSLING described the construction and organisation of the Swedish nVF.aa facility which is based on a J E M 1000-D electron microscope. Operation of the microscope at 1000kV began in June 1969 approximately 2 months after delivery (final approval of the instrument occurred 15 August, 1969). The column is mounted on an isolated concrete block to minimise vibration and a resolution of 4.5A has been achieved. The specimen chamber has a liquid nitrogen-cooled anti,conta~nafion trap. Special attachments include a tilting hot stage (800°C), cold stage (--120°C) and non-tilting tensile device. The facility is operated for the following con~rfinm
NEW FACILITIES AND PLANS FOR HVEM
2.80
of Swedish public and private materials research organisations; Swedish Institute for Metal Research (R. Kiessling, B. Aronsson, S. Modin) ; Royal Institute of Technology (Physical Metallurgy, M. HiUert, R. Lagneborg; Solid State Physics, H. Astr6m; Physical Clmnistry, E. Forslind; Polymer Technology, B. Ranby); Research Institute of National Defence (L. Holm); Sandvick Steel Company (G. Persson). Initial applications of the microscope include the plastic deformation of some steel types, structural studies of protective oxide layers in austenitic stainless steel, studies of metals deformed at high deformation velocities, and the distribution of certain inorganic pigments in polymers. G. DuPotr'," announced the completion and preliminary operation of a new microscope developed in collaboration with F. Perrier designed for a maximum accelerating voltage of 3MV which has already reached 2.2MV. He surprised the participants with the first public presentation of micrographs taken at 1.8mV which showed striking clarity and definition. The new microscope is of imposing dimensions as the lens column is 3.9 metres in length, 93cm in diameter and weighs 22 tons. The high voltage generator and accelerator are insulated with pressurised gas and housed in a concrete chamber 8 metres in height. Considerable effort was required to provide adequate protection against the extremely penetrating X-rays produced at such high voltages. Dupouy predicted that further increases in operating voltages would require approaches other than scaled up conventional lens systems. Brief reports were also presented on the status of additional new and planned facilities. K. J. VAN OOSTmJM told of an experimental 1000kV microscope designed and constructed at Philips Eindhoven. The machine was completed several months ago and is undergoing checkout and calibration tests. R. Gross described the 500kV RCA instrument at the University of Virginia which has been operating since the first part of this year under the direction of Dr. H. G. F. Wilsdorf. G. TaOMAS reported on the initial operation of the recently established facility at the University of California based on a Hitachi 650. R. E. WORSH~ et al. described the design concept and status of the construction of a high resolution device, intended for moderate range operation (100-500kV). The ultimate goal is point-to-point resolution of at least 1A. This is being approached via superconducting lenses, field emission gun, quadrupole-octupole corrector, and highly regulated voltage supply. H. FtJJXTA briefly mentioned that a 2-3MeV microscope is under consideration at Osaka University, Japan. Several additional high voltage facilities in England will utilise the AEI EM-7 1000kV electron microscope. It is anticipated that the first installation, scheduled for Harwell, will be complete in the autumn of 1969 followed by deliveries to the National Physical Laboratory, Imperial College, and Oxford University during 1970. G. K. WIr~LmMSONdescribed the plans for HWM facility based on a Hitachi HU-1000 which will be housed in a new building of relatively simple design and modest cost linked to an existing electron microscope laboratory. The microscope will become operational in December 1969. He emphasised that the advantage of increased
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penetration of HVEM for examining reactor materials, especially uranium (metal, oxides and carbides), was important for their efforts to understand and solve pressing problems relating to the swelling and other behaviour of fuel elements. The purchase of the microscope by Central Electricity Generating Board was justified as a major part of the research and development provision to protect an investment in nuclear reactors approaching 2 billion dollars. D. F. GmBONS described their facility which will consist of a Hitachi HU-650 B microscope under the direction of T. E. Mitchell, anticipated to become operational during the summer of 1970. The research programme will be equally divided between biological and materials science projects. The initial biological applications will include research on the crystal matrix and organic collagen sheath relationship in hard tissue (tooth enamel), determination of the secretion and orientation of chitinprotein microfibres in insect cuticles, and the development of microchambers to obtain diffraction patterns from collagen. The initial materials science applications include research on phase separation in glasses, deformation processes in refractory metals, and the relationship of the crystallite structure in thin magnetic films to the saturation induction and field dependence of the magnetisation. S. M. OHR stated that the Oak Ridge facility will also employ a Hitachi HU-650 and that it is expected to begin to function in the spring of 1970.
PLATE I
Figure 1. Schematic diagram of the column of the 3mV microscope. Gaston Dupouy, Toulouse.
M/cron, 1969, 1:279-282 with I plate
NEW FACILITIES AND PLANS FOR H V E M
. Vers ta canon
~rescent
_ LEGENDE_ Acier Laiton
PTJ~ Duratumin. Ptomb de pompage
chambre photographique
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282 Plate I