Open Access250 MHz passive Q‐modulator for reflection resonators
Author(s) -
Epel Boris,
Sundramoorthy Subramanian V.,
Halpern Howard J.
Publication year - 2017
Publication title -
concepts in magnetic resonance part b: magnetic resonance engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.286
H-Index - 32
eISSN - 1552-504X
pISSN - 1552-5031
DOI - 10.1002/cmr.b.21356
Subject(s) - resonator , signal (programming language) , pulse (music) , physics , q factor , modulation (music) , optics , noise (video) , reflection (computer programming) , pulse width modulation , frequency modulation , excitation , resonance (particle physics) , quality (philosophy) , power (physics) , optoelectronics , radio frequency , electrical engineering , acoustics , atomic physics , computer science , engineering , quantum mechanics , artificial intelligence , detector , image (mathematics) , programming language
Abstract A simple scheme for dynamically switching the quality factor, Q, of a loop‐gap resonator (LGR); working at 250 MHz is presented. The addition of this Q‐modulator resulted in 30% improvement in electron paramagnetic resonance imager signal‐to‐noise ratio. During pulse excitation, this scheme lowered the Q, while higher Q was obtained during signal detection. These conditions favored the image acquisition. The Q‐modulator is passive; the transition between different states was actuated by the radio frequency power itself.