Differences

This shows you the differences between two versions of the page.

--- nmr_probes [2023/10/31 17:14]
swartzj [Description]
+++ nmr_probes [2024/01/10 17:36]
swartzj [Spectrograph NMR GUI "locks" in noise or does not see weak resonance]
@@ Line 113: / Line 113: @@
-==== Spectrograph NMR GUI "locks" in noise or does not see weak resonance====
+==== NMR reading sometimes takes too long (> 30 min) ====
-  * This is typically the case when the thresholds in the NMR GUI are not set properly. If they are too low, the program may lock in noise. Conversely, if the thresholds are too high, it may miss a weak resonance.
-  * Threshold for the Spectrograph resonance can be adjusted by hand in the Spectrograph NMR GUI. In general, a threshold 0.15 mV is good for normal NMR signals, whereas 0.10 mV may be necessary if the signal are too weak.
+This is typically caused by one of two possible factors:
+. The signal is weak, and so the NMR "latches" on noise peaks. This is typically the case when the thresholds in the NMR GUI are not set properly. If they are too low, the program may lock in noise. Conversely, if the thresholds are too high, it may miss a weak resonance.
+  * 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.
+  * In general, a threshold 0.15 mV is good for normal NMR signals, whereas 0.10 mV may be necessary if the signal are too weak.
+. Initial field where NMR starts scanning is far away from actual value (this has only been seen with Spectrograph)
+  * Check what field is NMR scanning and compare with field read by neighboring NMR.
+  * If it is too far, stop NMR; enter field (in T) and click “Set”; start NMR.

S800 Documentation

User Tools

Site Tools

Differences

Page Tools