Experimental setup for investigation of nanoclusters at cryogenic temperatures by electron spin resonance and optical spectroscopies

• Published in: Review of scientific instruments 2014-07, Vol.85 (7), p.073906-073906
• Main Authors: Mao, S, Meraki, A, McColgan, P T, Shemelin, V, Khmelenko, V V, Lee, D M
• Format: Article
• Language: English
• Subjects: ABLATION; CAMERAS; CHARGE-COUPLED DEVICES; Chemical reactions; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Cryogenic temperature; CRYOSTATS; DISSOCIATION; Electron paramagnetic resonance; Electron spin; ELECTRON SPIN RESONANCE; Electrons; Fluids; Free radicals; HELIUM; HELIUM 4; IMPURITIES; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Laser ablation; MOLECULAR CLUSTERS; MOLECULES; Nanoclusters; NANOSCIENCE AND NANOTECHNOLOGY; NANOSTRUCTURES; Organic chemistry; PHOTOLYSIS; RADICALS; Radio frequency discharge; RF discharge-pumped lasers; Scientific apparatus & instruments; SPECTROSCOPY; Spin resonance; SUPERFLUIDITY; TEMPERATURE RANGE 0065-0273 K
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.4891189

We present the design and performance of an experimental setup for simultaneous electron spin resonance (ESR) and optical studies of nanoclusters with stabilized free radicals at cryogenic temperatures. A gas mixture of impurities and helium after passing through a RF discharge for dissociation of molecules is directed onto the surface of superfluid helium to form the nanoclusters of impurities. A specially designed ESR cavity operated in the TE011 mode allows optical access to the sample. The cavity is incorporated into a homemade insert which is placed inside a variable temperature insert of a Janis (4)He cryostat. The temperature range for sample investigation is 1.25-300 K. A Bruker EPR 300E and Andor 500i optical spectrograph incorporated with a Newton EMCCD camera are used for ESR and optical registration, respectively. The current experimental system makes it possible to study the ESR and optical spectra of impurity-helium condensates simultaneously. The setup allows a broad range of research at low temperatures including optically detected magnetic resonance, studies of chemical processes of the active species produced by photolysis in solid matrices, and investigations of nanoclusters produced by laser ablation in superfluid helium.