A new low‐energy‐electron‐diffraction (LEED) instrument is described that combines resistive‐anode‐based position‐sensitive detectors with a high‐resolution electron gun capable of producing a beam having high spatial coherence (large instrument transfer width). The system produces digitized images of LEED patterns as well as high‐resolution spot profiles of individual beams using incident currents in the picoampere range, thus vastly reducing or eliminating electron beam damage to sensitive surfaces. The display resolution of both spot profile and full display images is 1024×1024 channels, and the dynamic range is 16 bits (≊104) per channel. The resistive anode pulse processing electronics limits maximum data acquisition rates to 1×106 s−1. Specially developed software permits manipulation and numerical processing of the digitized two‐dimensional images at full resolution to produce spot contour maps, spot line profiles along arbitrary directions, Fourier transforms of spot profiles, integrated spot intensities, and intensity vs voltage curves with suitably subtracted background.

1.
J. B. Pendry, Low Energy Electron Diffraction (Academic, New York, 1974).
2.
M. A. Van Hove and S. Y. Tong, Surface Crystallography by LEED (Springer, Berlin, 1979).
3.
M. A. Van Hove, W. H. Weinberg, and C.-M. Chan, Low-Energy Electron Diffraction (Springer, Berlin, 1986).
4.
M. Henzler, in Electron Spectroscopy for Surface Analysis, edited by H. Ibach (Springer, Berlin, 1977).
5.
M. G.
Lagally
 and
J. A.
Martin
,
Rev. Sci. Instrum.
54
,
1273
(
1983
).
Google Scholar
Crossref
Search ADS
 
6.
D. W.
Kruger
,
D. E.
Savage
, and
M. G.
Lagally
,
Phys. Rev. Lett.
63
,
402
(
1989
).
Google Scholar
Crossref
Search ADS
PubMed
 
7.
J. B. Pendry, in The Structure of Surfaces, edited by M. A. Van Hove and S. Y. Tong (Springer, Berlin, 1985).
8.
Leybold Inc., SPA LEED, Export, PA.
9.
Omicron Associates, Spot Profile Analysis LEED, Pittsburgh, PA.
10.
M. D.
Chinn
 and
S. C.
Fain
,
J. Vac. Sci. Technol.
14
314
(
1977
).
Google Scholar
Crossref
Search ADS
 
11.
P. C.
Stair
,
Rev. Sci. Instrum.
51
,
132
(
1980
).
Google Scholar
Crossref
Search ADS
 
12.
E. G.
McRae
,
R. A.
Malic
, and
D. A.
Kapilow
,
Rev. Sci. Instrum.
56
,
2077
(
1985
).
Google Scholar
Crossref
Search ADS
 
13.
Two resistive anode detectors and position-sensing electronics are supplied by Quantar Technology Inc., Santa Cruz, CA.
14.
Y.
Cao
 and
E. H.
Conrad
,
Rev. Sci. Instrum.
60
,
2642
(
1989
).
Google Scholar
Crossref
Search ADS
 
15.
B. L. Clothier, M. A. Thesis, University of Texas, 1991.
16.
Kimball Physics Inc., model ES-423B, Wilton, NH.
17.
Perkin-Elmer Inc., Eden Prairie, MN.
18.
A software package SIMION is used for the simulations. SIMION is written by D. A. Dahl and J. E. Delmore at the Idaho National Engineering Laboratory, Idaho.
19.
Buckbee-Mears Operation, St. Paul, MN.
20.
R. L.
Park
,
J. E.
Houston
, and
D. G.
Schreiner
,
Rev. Sci. Instrum.
42
,
60
(
1971
).
Google Scholar
Crossref
Search ADS
 
21.
For a more detailed discussion about transfer width, please see
G.
Comsa
,
Surf. Sci.
81
,
57
(
1979
).
Google Scholar
Crossref
Search ADS
 
22.
To resolve the problem associated with the Moire effect, we can either use hemispherical grids with higher mesh density or remove the entire grid system. The retarding fields can be supplied by biasing the first MCP when the grid system is removed. Our current grid system has a mesh density of 100 lines per inch with 83% transmission.
23.
G. S.
Glander
 and
M. B.
Webb
,
Surf. Sci.
224
,
60
(
1989
).
Google Scholar
Crossref
Search ADS
 
This content is only available via PDF.
© 1993 American Institute of Physics.
1993
American Institute of Physics
You do not currently have access to this content.