Lawrence J. LeGore

Application of the interleaved comb chopper to time-of-flight electron spectrometry

Abstract We examined the use of the interleaved comb chopper for time-of-flight electron spectrometry. Both static and dynamic behaviors are simulated theoretically and measured experimentally, with very good agreement. The finite penetration of the field beyond the plane of the chopper leads to non-ideal chopper response, which is characterized in terms of an “energy corruption” effect and a lead or lag in the time at which the beam responds to the chopper potential.

Advantages of maximum likelihood methods for PRBS modulated TOF electron spectrometry

Abstract We consider the recovery of spectra from pseudo-random binary sequence (PRBS) modulated TOF-HREELS data. The effects of the Poisson noise distribution and the non-ideal behavior of an “interleaved comb” chopper are simulated. We show, for the first time, that maximum likelihood methods can be combined with PRBS modulation to achieve resolution enhancement, while properly accounting for the Poisson noise distribution and artifacts introduced by the chopper. Our results indicate that meV resolution, similar to that of modern high resolution electron spectrometers, can be achieved with a dramatic performance advantage over conventional, serial detection analyzers.