EPR Resonators
EPR Resonators
EPR Resonators
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<strong>EPR</strong> with Microcoils<br />
DieterSuter
Bulk <strong>EPR</strong> spectra<br />
liquid / solid<br />
14 N@C60<br />
Atom centered<br />
Æ all <strong>EPR</strong> transitions degnerate<br />
B<br />
Motivation<br />
N@C60 on Si:<br />
Symmetry broken<br />
2<br />
H ~ S ZF Z
<strong>EPR</strong> Sensitivity<br />
Specified sensitivity of<br />
ELEXSYS spectrometer (Bruker):<br />
8 . 10 8 spins/Gauss<br />
Linewidth of N@C60 : 0.015 Gauss<br />
Knapp et al., Chem. Phys. Lett. 272, 433-437 (1997).<br />
Theoretical detection limit :<br />
1.2 . 10 7 spins<br />
~ 3 µm x 3 µm monolayer
Cavity resonator<br />
Size determined by resonance frequency<br />
<strong>EPR</strong> <strong>Resonators</strong><br />
~ l/2 ~ 1 cm
NMR <strong>Resonators</strong>
A.G. Webb, Progr. NMR Spectr. 31, 1 (1997).<br />
S/N Scaling
Signal ~ magnetic flux<br />
through coil<br />
Spin Detection<br />
F = 0<br />
F ≠ 0
NMR probe with 1.5 mm coil<br />
M. Stumber, M. Geyer, H.R. Kalbitzer, K. Scheffzek,<br />
and U. Haeberlen, ‘Observation of slow dynamic<br />
exchange processes in Ras protein crystals by 31P solid<br />
state NMR spectroscopy’, J. Mol. Biol. 323, 899 (2002).<br />
Microcoils<br />
lithographic microcoil for NMR<br />
C. Massin, G. Boero, P. Eichenberger, P.A. Besse, and<br />
R.S. Popovic, ‘High-Q factor RF planar microcoils on<br />
glass substrates for NMR spectroscopy’, preprint.<br />
electronic<br />
filter
Au on GaAs<br />
Weizman Institute<br />
Initial Designs<br />
PCB, UniDO<br />
0.75 mm
“Micro”-coil with DPPH<br />
First results<br />
<strong>EPR</strong> Signal
Tuning of microcoils<br />
to Z = 50 W<br />
Use tuning<br />
stubs<br />
Loading of<br />
sample ?<br />
Challenges<br />
Optimize S/N<br />
Æ Multiturn coil ?
Ljiljana Udovicic<br />
The Team<br />
Ryszard Narkovic
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