Introduction - OCI BDL800IR Instruction Manual

1 Introduction

The Back-Display LEED-AUGER spectrometer is an instrument to measure the structure of
the first few atomic layers of crystalline surfaces based on the low energy electron diffraction
(LEED) effect. The spectrometer is also capable of measuring the elemental composition of a
surface via the analysis of Auger electrons. The basic instrument layout is a combination of a
hemispherical retarding-field analyzer, miniature electron gun, and a glass display.
The LEED technique has become an important experimental tool in the study of crystal
surface phenomena such as atomic structure of clean surfaces and chemisorbed layers, epi-
taxy, thermal etching, oxidation, phase transition, faceting, and many others. The AES tech-
nique is a major tool in materials research providing elemental surface analysis of surfaces
prepared by sputtering, annealing, deposition, etching, and others.
The Back-Display LEED-AUGER spectrometer is a compact instrument supplied in three
sizes. Model BDL800IR is adapted to fit an 8" CF flange, while model BDL600IR fits a 6"
CF flange and model BDL450 fits a 4.5" CF flange. The spectrometer optics comprises a set
of grids, a transparent screen coated with a P31 phosphor and conducting coating, and a min-
iature coaxially mounted electron gun. Units can optionally be equipped with a linear motion.
Digital LEED-AES power supply/controller, model LPS300-D, is designed to control all
models of INTEGRALEED optics in the LEED mode with a beam energy range of 5–750 eV
and in the AES mode with a beam energy range of 5–3000 eV. The controller is using on-
board microprocessor to execute programs and optical rotary encoders for settings. Models
LPS300-D and LOA10-AES constitute a complete analytical package for both LEED and
AES. Model LPS075-D operates in LEED mode only.
The High Voltage Generator supplies a sweep voltage modulated with a sine wave. The
unit comprises a precision oscillator, which delivers V
trolled by the AES software installed on a PC via USB.
The Low-noise Input Coupler provides 160–180 V biasing of the screen collector, band-
pass filtering, and signal pre-amplification.
6 Chapter 1 Introduction
up to 20 V. The generator is con-
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