Real-time computer-optimized electron coincidence spectrometer

Abstract

An electron coincidence spectrometer utilizing real-time optimization and control by a standard IBM 80286 personal computer is described. Details of the system hardware and software are presented together with a description of the optimization routine adopted for maintaining the tuning of the spectrometer and data acquisition. Data collected by the computer-controlled spectrometer for (e,2e) coincidence experiments are also presented.

Ionisation differential cross section measurements for N2at low incident energy in coplanar and non-coplanar geometries

“…In this way changes in the operating conditions of the spectrometer as the experiments proceeded could be minimised. Full details of the computer control and optimisation systems used in these experiments can be found in [19]. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3.…”

A novel spectrometer combining laser and electron excitation and deflection of atoms and molecules

“…These optocouplers are constructed from infrared TEMT88-PD photodiodes and SD5443-3 phototransistors. 16 The angle is determined when light passes through an accurately machined 0.5 mm aperture located in a flat aluminum plate attached to the detector. Reference signals from the optocoupler array are used as feedback control to the stepper motor driver, which feeds 700Ϯ20 steps between each measured angle.…”

Design of a non-magnetic translator for use in vacuum systems

“…The usual method adopted to adjust a component (such as a lens) external to a vacuum chamber is to use a high-resolution x yz-translator upon which the component is secured, thereby allowing accurate control of the position. These translators are routinely employed in optical and laser-based experiments, and most optical component distributors can supply extremely accurate adjusters for this purpose 3,4 . These adjusters usually employ ball or crossed roller bearings, and can provide interferometric accuracy and reproducibility.…”

“…It is therefore necessary to consider a method of providing accurate translation inside the vacuum chamber 3 Newport Corp., 1791 Deere Avenue, Irvine, CA 92606, USA (www.newport.com). 4 Melles Griot Corp. 2051 Palomar Airport Road, Carlsbad, CA 92009, USA (www.mellesgriot.com). without the use of lubrication and without the use of magnetic materials.…”