A multiparameter data acquisition system based on universal serial bus interface for electron momentum spectrometer

Abstract

A versatile multiparameter data acquisition system based on universal serial bus (USB) interface was designed and has been used on the electron momentum spectromenter. Digitized data were first buffered in a FIFO memory in an event-by-event mode with a check bit, and then transferred to computer through the USB interface. USB interface combined with a microcontroller unit provides much flexibility for data acquisition and experimental controls. The operation performance of the system is demonstrated in the measurement of electron momentum spectra of CH2F2 molecules.

New Diagnostic of the Most Populated Conformer of Tetrahydrofuran in the Gas Phase

“…The EMS measurements for THF were undertaken with the symmetric non-coplanar geometry using a high-resolution and high-sensitivity (e, 2e) electron momentum spectrometer recently developed at Tsinghua University . With the novel double toroidal analyzer and the two-dimension position-sensitive detectors, the collect efficiency is about 2 orders of magnitude higher than that of our previous spectrometer, , so the statistical accuracy and the reliability have been improved significantly. In a number of recent EMS experiments aiming at testing the plane wave impulse approximation (PWIA), the Tsinghua EMS experimental group has been able to achieve a wider range of impact energies, from as low as 400 eV to as high as 2400 eV − for molecules such as ethylene, HOMOs of 1,3-cyclohexadiene, and HOMO of oxygen .…”

Improvements on the third generation of electron momentum spectrometer

“…The electronics for data acquisition is similar to that used in our EMS-2 spectrometer. [39] The charge division method can provide a very good ratio of signal to noise but the signals are rather slow, therefore there appear pulse pile-ups due to the high count rate, typically 10 k/s. Considering the high count rate of EMS-3 spectrometer, the multi-parameter acquisition system is extended with a pile-up rejector.…”

Dynamic effects in electron momentum spectroscopy of sulfur hexafluoride

“…The experiment was performed using a high resolution and high efficiency electron momentum spectrometer. The detail of this apparatus has been reported in previous works [16][17][18][19] and hence will not be repeated here. Briefly, it utilizes a non-coplanar symmetric geometry, i.e.…”