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Title: A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy

Abstract

We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 10{sup 7} detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes. .

Authors:
; ;  [1]
  1. The Rowland Institute at Harvard University (United States)
Publication Date:
OSTI Identifier:
22776791
Resource Type:
Journal Article
Journal Name:
Journal of the American Society for Mass Spectrometry
Additional Journal Information:
Journal Volume: 29; Journal Issue: 2; Conference: 32. Asilomar conference on novel instrumentation in MS and ion mobility, Pacific Grove, CA (United States), 14-18 Oct 2016; Other Information: Copyright (c) 2018 American Society for Mass Spectrometry; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-0305
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; APERTURES; CRYOGENICS; ELECTRIC FIELDS; ELECTRODES; EXCITATION; EXCITED STATES; FLUORESCENCE; FLUORESCENCE SPECTROSCOPY; ION SPECTROSCOPY; IONS; RELAXATION; TEMPERATURE CONTROL; TRAPS

Citation Formats

Rajagopal, Vaishnavi, Stokes, Chris, and Ferzoco, Alessandra. A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy. United States: N. p., 2018. Web. doi:10.1007/S13361-017-1763-3.
Rajagopal, Vaishnavi, Stokes, Chris, & Ferzoco, Alessandra. A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy. United States. doi:10.1007/S13361-017-1763-3.
Rajagopal, Vaishnavi, Stokes, Chris, and Ferzoco, Alessandra. Thu . "A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy". United States. doi:10.1007/S13361-017-1763-3.
@article{osti_22776791,
title = {A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy},
author = {Rajagopal, Vaishnavi and Stokes, Chris and Ferzoco, Alessandra},
abstractNote = {We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 10{sup 7} detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes. .},
doi = {10.1007/S13361-017-1763-3},
journal = {Journal of the American Society for Mass Spectrometry},
issn = {1044-0305},
number = 2,
volume = 29,
place = {United States},
year = {2018},
month = {2}
}