The ANL HVEM-tandem accelerator facilities

1978 ◽  
Vol 36 (1) ◽  
pp. 76-77
Author(s):  
R. Lyles ◽  
A. Taylor ◽  
K. Merkle ◽  
P. Okamoto ◽  
P. Pronko
Keyword(s):  
Materials Science ◽  
Ion Trap ◽  
Ion Beam ◽  
Dark Field ◽  
Negative Ion ◽  
Target Area ◽  
Tandem Accelerator ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Ion Accelerator

The ANL HVEM-TANDEM accelerator facilities are being developed to provide a unique combination of techniques for basic studies in the field of materials science. In addition to the methods of high voltage electron microscopy, the ion accelerator system will provide ion beam analysis and ion bombardment - implantation capability either in the HVEM or in an adjacent target area. The installation of the HVEM is completed and constitutes the first step in the development of a materials research laboratory, which will include a HVEM/ion beam interface with a 300 kV ion accelerator and a 2-MV tandem accelerator. The plan layout of these facilities is shown schematically in Figure 1.ANL's 1.2 MeV HVEM is an improved version of the AEI EM-7 and has a guaranteed resolution of 5 Å point-to-point. The design of the microscope contains a number of unique features. These include a specially designed ion beam access flight tube, instrumentation for two independently adjustable dark field conditions, 100 - 1200 kV continuous-mode accelerating voltage selection, a negative ion trap, and an ion- pumped specimen chamber.

The New ANL Materials Science HVEM Facility

1977 ◽  
Vol 35 ◽  
pp. 98-99
Author(s):  
R. L. Lyles ◽  
K. L. Merkle ◽  
P. Okamoto
Keyword(s):  
Materials Science ◽  
Ion Trap ◽  
Ion Beam ◽  
National Laboratory ◽  
High Vacuum ◽  
Argonne National Laboratory ◽  
Dark Field ◽  
Negative Ion ◽  
Tandem Accelerator ◽  
Materials Research

A new transmission HVEM facility has been completed at Argonne National Laboratory. The ANL HVEM provides the beginning of a dedicated materials research laboratory which will subsequently include an interface with a 2 MV tandem accelerator and a low energy ion injector for iri situ ion irradiation and ion beam analysis experiments (Figure 1).The microscope, an improved version of the AEI EM-7, has an accelerating voltage of 1.2 MeV. Moreover, a number of exceptional features have been designed into the instrument which will significantly enhance its usefulness in materials research: 1. High vacuum specimen chamber with direct ion pumping. 2. Instrumentation for two independent and alternatively selectable dark field conditions. 3. Negative ion trap. 4. Ion beam interface. In addition, a helium temperature, side entry, cooling stage is being developed at ANL . The negative ion trap and the ion beam interface are features that have not been previously included in HVEM designs.

scholarly journals Some Current and Future Trends of High Voltage Transmission Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 2-3
Author(s):  
Gareth Thomas
Keyword(s):  
Electron Microscopy ◽  
High Voltage ◽  
Materials Science ◽  
Future Trends ◽  
Light Elements ◽  
Special Effects ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Transmission Electron ◽  
Resolution Level

The Optimum Voltages for Electron Microscopy – The advantages of high voltage electron microscopy are now well established, and many applications, such as use of environmental cells both in metallurgy and biology, are now possible. However recent experiments at Toulouse indicate that except for light elements, there is no appreciable gain in transmission for a given resolution level as the energy is increased above 1 MeV (see Fig. 1). These results are not as optimistic as theory might indicate. Special effects such as critical voltages above 1 MeV are of interest, but knock-on radiation damage imposes limitations on many applications. Thus it would appear that 1 MeV is a reasonable upper limit for most applications in materials science.

Development of continuous wave high voltage negative ion beam injector for tandem accelerator

2019 ◽  
Vol 90 (12) ◽  
pp. 123314
Author(s):  
A. Sanin ◽  
Yu. Belchenko ◽  
A. Ivanov ◽  
A. Gmyrya
Keyword(s):  
High Voltage ◽  
Continuous Wave ◽  
Ion Beam ◽  
Negative Ion ◽  
Tandem Accelerator

Characterization and light emission properties of osmium silicides synthesized by low energy ion implantation

2008 ◽  
Vol 1066 ◽  
Author(s):  
Prakash R. Poudel ◽  
K. Hossain ◽  
J. Li ◽  
B. Gorman ◽  
A. Neogi ◽  
...  
Keyword(s):  
Light Emission ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Ion Source ◽  
Alpha Particles ◽  
Low Energy ◽  
Negative Ion ◽  
Tandem Accelerator ◽  
Cross Sectional ◽  
Osmium Silicide

ABSTRACTLow energy (55 KeV) Osmium ( Os− ) negative ion beam was used to implant (5×1016 atoms/cm2 ) into p-type-Si (100). The implantation was performed with the ion source of a National Electrostatic Corp. 3 MV Tandem accelerator. The implanted sample was subsequently annealed at 650 °C in a gas mixture that was 4% H2 + 96% Ar. Rutherford Backscattering spectrometry (RBS) analysis with 1.5 MeV Alpha particles was used to monitor the precipitate formation. Photoluminescence (PL) measurements were also performed to study possible applications of silicides in light emission. Cross-sectional Scanning Electron Microscopy (X-SEM) was performed for topographic image of the implanted region. RBS along with PL measurements indicate that the presence of osmium silicide (Os2Si3) phase for light emission in the implanted region of the sample.

Ultra-High Voltage Electron Microscopy (1-3 MeV) of Biological Macromolecules

1972 ◽  
Vol 30 ◽  
pp. 182-183
Author(s):  
William H. Massover
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Biological Macromolecules ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Dark Field Imaging ◽  
Beam Stop ◽  
Imaging Conditions ◽  
Field Imaging ◽  
Very High

Important difficulties persist for high resolution (= pauci-atomic) electron microscopy of biological macromolecules in terms of obtaining (a) higher effective resolution, (b) decreased specimen damage induced by the electron beam irradiation, and (c) adequate image contrast without the use of extraneous contrasting agents. Electron microscopy at elevated accelerating tensions can largely provide a solution to some of these very problems. Use of a 46μm diameter beam stop (at the level of the objective aperture) for 1000 kV, and of a 23μm diameter beam stop for 3000 kV, produces very high contrast dark field imaging conditions that also retain a higher effective resolution than do the previous beam stop methods developed by Dupouy et al.

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