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nmr_probes [2024/01/10 17:36] swartzj [Spectrograph NMR GUI "locks" in noise or does not see weak resonance] |
nmr_probes [2024/06/01 16:35] (current) swartzj |
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====== NMR Control ===== | ====== NMR Control ===== | ||
- | Two digital oscilloscopes are dedicated to NMR readout – one for the analysis line NMRs and one for the spectrograph NMRs. The scopes are located in the S3 mezzanine. They are isolated from clean ground because | + | Two digital oscilloscopes are dedicated to NMR readout – one for the analysis line NMRs and one for the spectrograph NMRs. The scopes are located in the S3 mezzanine. They are isolated from clean ground because |
===== Motivation ===== | ===== Motivation ===== | ||
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* Simply turn it off, wait few seconds, and turn it back on | * Simply turn it off, wait few seconds, and turn it back on | ||
+ | ==== Error message: "/ | ||
+ | * In a new terminal, ssh to yourname@exp-s3-nmr, | ||
+ | * mv spectrograph.log spectrograph-yourname.log | ||
+ | * Now close the error message window and you should not have this problem anymore. | ||
==== NMR reading sometimes takes too long (> 30 min) ==== | ==== NMR reading sometimes takes too long (> 30 min) ==== | ||
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* This can be alleviated by changing the NMR thresholds (it can be done for each magnet in the analysis line, or for both magnets in the spectrograph). | * This can be alleviated by changing the NMR thresholds (it can be done for each magnet in the analysis line, or for both magnets in the spectrograph). | ||
* Stop NMR; enter new threshold (in Volts) and click “Set”; start NMR. | * Stop NMR; enter new threshold (in Volts) and click “Set”; start NMR. | ||
- | * In general, a threshold 0.15 mV is good for normal NMR signals, whereas 0.10 mV may be necessary if the signal | + | * In general, a threshold 0.15 mV is good for normal NMR signals, whereas 0.10 mV may be necessary if the signals |
2. Initial field where NMR starts scanning is far away from actual value (this has only been seen with Spectrograph) | 2. Initial field where NMR starts scanning is far away from actual value (this has only been seen with Spectrograph) |