...
The LIMS components for the NGR analysis are as follows:
Component Name |
Reported Name |
Units | Result Type (N = numeric, T = text) |
Description |
|---|---|---|---|---|
total_counts_per_sec | NGR total counts | cps | N | Rate of natural gamma radiation across the spectrum of ~0.1-3.0 MeV for a 10 cm section of core |
absolute_error | Error | cps | N | Inverse of the square root of total counts |
relative_error | Error (%) | none | N | Relative error of the measurement, defined as the absolute error divided by the number of counts, expressed as a percentage |
period | Measurement period | sec | N | Length of Live time for the NGR measurement (usually 300 sec) |
detector | NGR detector number | none | N | NaI(Tl) detector number, from 1 to 8 |
offset | Offset | cm | N | Location of measurement from top of section |
observed_length | Observed length | cm | N | Length of section as observed by NGR operator |
comments | Comment | none | T | Comment on the measurement, entered on sample entry screen |
archive_asman_id | Archive ASMAN ID | none | N | ASMAN database ID number for archived file folder |
archive_filename | Archive filename | none | T | ASMAN database filename for archived file folder |
summary_asman_id | Summary ASMAN ID | none | N | ASMAN database ID number for summary file |
summary_asman_id | Summary filename | none | T | ASMAN database filename for summary file |
run_asman_id | Run ASMAN ID | none | N | ASMAN database ID number for run file (logger data output file) |
run_asman_id | Run filename | none | T | ASMAN database filename for run file (logger data output file) |
Data Upload
- Once analysis is complete, open the uploader “MUT.” The icon is a dog face on the desktop but may also be found in START > ALL PROGRAMS > IODP.
- Log in to MUT (the PP technician can help with this).
- Usually, the uploader is set to automatically upload data (check the “automatic” button) but if troubleshooting, it may be desirable to leave this unchecked and trigger upload manually.
- Please remember to put the uploader back on automatic in normal operation so that NGR results are available to other scientists and technicians as soon as sections are completed!
...
Maintenance/Troubleshooting
Common Issues
Issue | Possible Causes | Solution |
|---|---|---|
Galil motor error | Red emergency stop button pressed | Resolve reason for emergency stop. Release emergency stop button. Open Galil control software and perform the following commands at the text prompt: MO SH This should clear the Galil amplifier error and allow the user to use the NGR software to find home and then continue work |
Amplifier overcurrent | Usually means a safety has been tripped and can be cleared the same way as the emergency stop button. Can, however, mean that that amplifier is damaged and must be replaced. Call an ET
If core is still inside the NGR chamber and the motor cannot be returned to service, follow these steps:
| |
No plastic or coincidence signal on CAEN counter | ISEG power unit fault or user inadvertently answered “yes” to the exit prompt | Open ISEG control software and follow startup procedure in this user guide. Look for error states; if not, continue measurements |
Low plastic count values on CAEN counter | ISEG channel failure on one or more channels | Open ISEG control software and check voltage and current levels to identify if a scintillator is “dark.” Move leads to open channels (default extra channel is #0) and document which channel is which detector (the door PMTs have a different voltage requirement than the hoop PMTs). |
No NaI(Tl) signal on CAEN counter | ORTEC modules have lost power | Call an ET |
High NaI(Tl) counts on CAEN counter | Internal contamination | Clean acrylic tube |
Short in a PMT base | Isolate which detector is causing the noise. This can be done by removing the MCA input lead one by one until the NaI(Tl) CAEN counts return to normal, or by running a core experiment and observing which detector takes too long to complete. That is the one with noise.
Real time = Live time + Dead time
Electrical noise causes more dead time, lengthening the measurement (real) time.
Corrective action may include checking the BNC cables and the PMT base underneath the NGR chamber (call an ET!) | |
NSK actuator (big silver actuator) sticks | Too long since the last lubrication | Open the NSK face plate and lubricate with the appropriate lubricant (ONLY!). Replacing the face plate can be tedious and it helps to do it with someone who has done it before |
Cooling fan making a lot of noise | Bad bearing on a fan motor | Call an ET to replace or clean fan |
...