NMR system for the frozen spin target to measure the polarisation CB collaboration meeting University of Edinburgh 2009 Nadja Frömmgen Institut für Kernphysik Universität Mainz 13.09.09 Nadja Frömmgen
Outline Principle of NMR Detection of the NMR signal NMR signal Performance test in July 2009 Conclusion and Outlook 13.09.09 Nadja Frömmgen
Principle of NMR Irradiation with a HF field NMR signal results from the difference between absorbed and emitted energy; voltage is induced in a receiver coil Signal is proportional to the population difference Polarisation 13.09.09 Nadja Frömmgen
coil 13.09.09 Nadja Frömmgen
How is the NMR signal detected? Series LC resonant circuit 13.09.09 Nadja Frömmgen
Series LC resonant circuit Resonance frequency tuning to the Larmor frequency of nucleus via changing C (varicap) „Resonance parabola“ 13.09.09 Nadja Frömmgen
Q-curve of the resonant circuit 13.09.09 Nadja Frömmgen
NMR signal TE: thermal equilibrium Measurement of the TE signal as exactly as possible to minimise the error of the polarisation measurement. 13.09.09 Nadja Frömmgen
July 2009 Performance test: cryostat, microwave apparatus & NMR system polarising magnet: 2.507 T cooled to ~26mK irradiated with microwaves (15mW) for 3.5 hours up to ~50% polarisation Successfull measurement: TE signal Polarised NMR signal Polarisation curve Relaxation curve 13.09.09 Nadja Frömmgen
TE-Signal In the meantime the noise on the signal could be reduced. 13.09.09 Nadja Frömmgen
Polarised NMR Signal ~ 50% polarisation 13.09.09 Nadja Frömmgen
Polarisation curve Polarisation [%] 2 ¼ hours 13.09.09 Nadja Frömmgen
Relaxation curve Polarisation [%] 30 minutes 13.09.09 Nadja Frömmgen
Conclusion and Outlook NMR-System is working well we expect a polarisation of P>90% and an error in the polarisation measurement of ~1.5% system linearity measurement several stability tests optimisation of the software by M. Korolija from Zagreb final test of the frozen spin target in October together with J. Usov, A. Neganov, N. Borisov and A. Lazarev from Dubna 13.09.09 Nadja Frömmgen
Thank you for your attention! 13.09.09 Nadja Frömmgen