{"title":"Selective Meter of Photomultiplier Currents for the Magnetic Circular Dichroism Spectroscopy in Reflected Light","authors":"Yu. V. Markin, Z. E. Kunkova","doi":"10.1134/S0020441224701021","DOIUrl":null,"url":null,"abstract":"<p>A relatively simple circuit of a selective meter of constant and variable components of the total current of a photomultiplier when recording magnetic circular dichroism spectra in reflected light using the method of light-wave phase modulation with the help of a photoelastic modulator is presented. The circuit implements a method for measuring the photomultiplier anode current using a load resistance <i>R</i><sub><i>L</i></sub> and a buffer preamplifier. The variable current component is extracted via compensation of the constant component of the total signal. The experimental techniques are described that make it possible to determine the optimal <i>R</i><sub><i>L</i></sub> value for which the influence of the input shunt capacitance is minimal in the frequency band of ~100 kHz. The main source and level of the parasitic photocurrent not associated with the incident monochromatic radiation are determined. The meter testing showed high efficiency of its use in magnetic circular dichroism spectroscopy. An algorithm for spectrum recording is proposed taking the change in the circular dichroism effect polarity into account. The performance and efficiency of the developed meter are illustrated by an example of measuring the magnetic circular dichroism spectrum of a GaMnAs film.</p>","PeriodicalId":587,"journal":{"name":"Instruments and Experimental Techniques","volume":"67 4","pages":"768 - 776"},"PeriodicalIF":0.4000,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Instruments and Experimental Techniques","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1134/S0020441224701021","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ENGINEERING, MULTIDISCIPLINARY","Score":null,"Total":0}
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Abstract
A relatively simple circuit of a selective meter of constant and variable components of the total current of a photomultiplier when recording magnetic circular dichroism spectra in reflected light using the method of light-wave phase modulation with the help of a photoelastic modulator is presented. The circuit implements a method for measuring the photomultiplier anode current using a load resistance RL and a buffer preamplifier. The variable current component is extracted via compensation of the constant component of the total signal. The experimental techniques are described that make it possible to determine the optimal RL value for which the influence of the input shunt capacitance is minimal in the frequency band of ~100 kHz. The main source and level of the parasitic photocurrent not associated with the incident monochromatic radiation are determined. The meter testing showed high efficiency of its use in magnetic circular dichroism spectroscopy. An algorithm for spectrum recording is proposed taking the change in the circular dichroism effect polarity into account. The performance and efficiency of the developed meter are illustrated by an example of measuring the magnetic circular dichroism spectrum of a GaMnAs film.
期刊介绍：
Instruments and Experimental Techniques is an international peer reviewed journal that publishes reviews describing advanced methods for physical measurements and techniques and original articles that present techniques for physical measurements, principles of operation, design, methods of application, and analysis of the operation of physical instruments used in all fields of experimental physics and when conducting measurements using physical methods and instruments in astronomy, natural sciences, chemistry, biology, medicine, and ecology.
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