MEDSI2016 - List of Authors (Escudero, C.)

Paper	Title	Page
WEPE15	High Frequency UHV Mechanical X-Ray Beam Chopper	339
	N González, C. Colldelram, C. Escudero, S. Ferrer ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	A mechanical chopper* has been designed and built to perform X-ray Absorption Spectroscopy (XAS) experiments with operating liquid electrochemical cells at NAPP end station of ALBA Synchrotron (BL24, CIRCE). When operating the cell, to separate the weak currents induced by the X-ray absorption process at the electrode in contact with the electrolyte (TEY signal) from the faradaic current set between the electrodes, the incoming beam must be chopped at a certain frequency (w). Then, using a lock in amplifier, the signal at this frequency w can be extracted and measured. When the chopper is located in the beam path, it produces pulses with a frequency w, modulating the TEY signal. The chopper developed at ALBA, with variable frequency, improves previous designs which used piezo-actuated choppers constrained to work at fixed oscillating frequencies*. The design consists of a slotted disk that spins around an axis by means of an UHV stepper motor. A LED and photodiode based UHV sensor ensures that frequency drifts do not affect the measurements. The motor is hold by an internally water cooled OFHC support, which allows long duration experiments at high speeds without stopping. Patent Registered ** Velasco-Velez et al, Science 2014, 346, 831-834
	Poster WEPE15 [4.043 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2016-WEPE15
About •	paper received ※ 09 September 2016 paper accepted ※ 16 September 2016 issue date ※ 22 June 2017
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

High Frequency UHV Mechanical X-Ray Beam Chopper

339

N González, C. Colldelram, C. Escudero, S. Ferrer
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

A mechanical chopper* has been designed and built to perform X-ray Absorption Spectroscopy (XAS) experiments with operating liquid electrochemical cells at NAPP end station of ALBA Synchrotron (BL24, CIRCE). When operating the cell, to separate the weak currents induced by the X-ray absorption process at the electrode in contact with the electrolyte (TEY signal) from the faradaic current set between the electrodes, the incoming beam must be chopped at a certain frequency (w). Then, using a lock in amplifier, the signal at this frequency w can be extracted and measured. When the chopper is located in the beam path, it produces pulses with a frequency w, modulating the TEY signal. The chopper developed at ALBA, with variable frequency, improves previous designs which used piezo-actuated choppers constrained to work at fixed oscillating frequencies**. The design consists of a slotted disk that spins around an axis by means of an UHV stepper motor. A LED and photodiode based UHV sensor ensures that frequency drifts do not affect the measurements. The motor is hold by an internally water cooled OFHC support, which allows long duration experiments at high speeds without stopping.
* Patent Registered
** Velasco-Velez et al, Science 2014, 346, 831-834

Poster WEPE15 [4.043 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-MEDSI2016-WEPE15

About •

paper received ※ 09 September 2016 paper accepted ※ 16 September 2016 issue date ※ 22 June 2017

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)