Software for versatile HFEPR spectrometer

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Even though nowadays some High Frequency Electron Paramagnetic Resonance (HFEPR) spectrometers are commercially available, most of them are still custom-built machines. A versatile HFEPR spectrometer with a Frequency Rapid Scanning (FRaScan) feature was built at CEITEC BUT [1]. A specific software solution for control of spectrometer was developed in LabVIEW [2] because it simplifies memory management, parallel execution, and communication with instruments via standard interfaces. The software is composed of individual modules for each instrumental part and main controller, which are connected via messaging service. This allows modules to run independently on each other, distribute tasks in threads and decrease average CPU load. The main controller is the top software component that provides an event driven user interface, as well as execution of a measurement routine and distribution of messages to modules. Currently, there are 3 types of user interface for different tasks. One for Continuous Wave (CW) measurements, second for Frequency Domain Magnetic Resonance (FDMR) measurements and third for Zeeman diagram measurements [3]. All of them have a similar design and share most of the back-end components. In case of CW and FDMR measurements it is possible to use a scripting feature to automatically execute a sequence of measurements. An integrated script editor utility can generate a batch of measurement sequence with sweep of desired parameter such as microwave frequency or magnetic field, orientation and temperature. Because FDMR measurements are much faster to perform and can yield a large data, the TDMS file format was used to organise datasets obtained from whole measurement sequence. The Zeeman diagram measurements are done by performing an FDMR measurements during continuous sweep of a magnetic field To demonstrate capabilities of spectrometer and its automated control we performed a measurements on single crystal of copper acetate as a model system for molecular magnetism. Measurements in a frequency range 205-245 GHz, at temperature 200 K and magnetic field 7.5 T were done in less than 2 hours for 280 orientations with step 1 degree. For comparison, alike measurements in a CW mode would take approximately 30 hours. Obtained data were post processed in orientation vs frequency map. Additionally, a Zeeman diagram was measured in a field range 4.5 to 9 T, and a frequency range 180 to 240 GHz. ________________________________________ References: [1] A. Sojka, M. Šedivý, O. Laguta, Electron Paramagnetic Reonance 2020, 27, 214-252 (DOI:10.1039/9781839162534-00214). [2] C.J. Kalkman, J Clin Monitor Comput. 1995, 11, 51-58 (DOI:10.1007/BF01627421). [3] P. Neugebauer, D. Bloss, R. Marx, Phys. Chem. Chem. Phys. 2018, 20, 15528-15534 (DOI:10.1039/C7CP07443C).

High Frequency Electron Paramagnetic Resonance, Frequency Domain Magnetic Resonance, LabVIEW, automation

ŠEDIVÝ, M.; SOJKA, A.; SANTANA, V.; GABRIŠ, A.; LAGUTA, O.; NEUGEBAUER, P.

5. 7. 2021

Narodna in univerzitetna knjižnica

Ljubljana

270

270

1

https://www.dlib.si/details/URN:NBN:SI:DOC-XTTC5Y0B