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Standard Operating Procedure - Paleomagnetism Lab
March 2018
The Paleomagnetics Lab technician shares his/her duties between the Core Lab and the Paleomagnetics Lab. For details on the Core Lab duties, refer to the Core Lab SOP.
I. PRE EXPEDITION
- See General JRSO Shipboard Technical Staff SOP
II. PORT CALL - Start of an Expedition
Cryogenic Magnetometer
- Check the vital signs of the Cryogenic Magnetometer. Use the electronics interfaces to measure the vital signs inside the magnetometer: SQUID temperature and shield temperature. Record the values on the log sheet.
- Check water level and condition inside the Haskris. Check the CryoWATCH software to monitor the compressor oil and water temperatures. Create a new log file for the expedition. For more detailed instructions refer to the SRM user guide.
- If a service call is scheduled, make sure you prepare all supplies necessary for it. Find the service representative.
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- Measure the interior field of the magnetometer using the 3-axis fluxgate ("field profile"). Use the DAFI utility in the IMS-SRM software. Save the excel file to IODP Share: Pmag_Documents: SRM: Field Profiles. Each file should be labeled with the date of measurement.
- If it is necessary to heat the SQUIDs to release a trapped field, follow the field trapping procedure in the user guide.
- Check the field produced by the degauss coils within the SRM using the axial and transverse Hall probes
- Introduce scientists to the cryomagnetometer and run basic measurements, such as:
- Clean the tray and demagnetize at a field of 30 mT or higher and measure the tray. Measure the tray as a fake sample and compare results to ensure corrections are done properly. This should be done with the section half and, if applicable, the discrete tray.
- Conduct positioning tests along the track with a section half tray. Testing should be done with an empty, light tray and a weighted, heavy tray. Check discrete boat positioning as well.
- Measure a split core or play core.
- Check to see if any regular maintenance projects need to be completed. Specifically check if the adsorber in the Cryomech compressor is due for replacement. If the bi-annual replacement of the adsorber is required, swap the entire Cryomech compressor with the spare compressor. Record the date of the change (place sticker on compressor).
- Provide safety tour to all scientists who work in the Paleomagnetic lab area. Ensure all scientists understand the safety concern and sign document required
III. SITE PREPARATION - Prior to arrival on site and core on deck
The following is a list of actions that should be accomplished prior to arriving at the first site. On cruises with short transit times before reaching the first site it is advisable to perform as many of the preparations in port as possible.
Paleomagnetics Lab
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- Assist in preparing to receive cores according to Corelab SOP
IV. DURING CORING OPERATIONS
The following is a list of actions that are accomplished once on site by technicians alone or cooperatively with the scientists assigned to the laboratory for an expedition.
A. SAMPLING
The basic magnetic measurements are conducted on whole/split sections and discrete samples:
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- Remain in contact with the Core Tech and Operations Manager while orienting APC cores. Make sure that the Flexit or MI5 Icefield Tools are exchanged every 8-12 hours.
- Check Flexit battery voltages from the raw survey file and change the batteries when the voltage is below 8.5V. Check the battery voltage on the MI5 Icefield tool at the start of each survey. If the batteries are at 8.5V switch them out before starting a survey.
- Upload Cryogenic Magnetometer data, orientation data, JR6 data, and Kappabridge data to LIMS using MegaUploadaTron. Cancel any duplicate uploads or remeasured runs after consulting with the paleomagnetists.
- Clean and demagnetize the tray of Cryogenic Magnetometer at each change of shift or whenever deemed necessary (usually done by the scientists). Wipe down the tray with isopropyl alcohol and Kimwipes when cleaning. It's especially important to keep the track and boat clean when the sediment is changing from high intensity core samples to low intensity. Treat the bottom of the boat with antistatic liquid as needed to help minimize flux jumping.
- Once a week check and record vital signs of the Cryogenic magnetometer and enter the data into the vital signs sheet and include in the tech report at the end of the expedition.
- Ensure that all instruments are free of dirt, lubricated and fully operational in the lab.
- Perform core lab duties according to Corelab SOP
- Maintain good notes or a logbook for each instrument to document problems encountered and to monitor changes in parameters.
- Check and maintain your inventory on a regular basis and submit orders to the Assistant lab officer. This includes both inventory and non-inventory items.
- Update shipboard manuals and cookbooks on a regular basis.
V. DURING TRANSITS
- Continue processing cores through the lab as described above
VI. DURING EXPEDITIONS
A. MAINTENANCE
In the Paleomagnetics Lab, a lot of the maintenance takes place on a daily or weekly basis during the expeditions as partially listed in the section above. However, for some instruments, maintenance is only required on a monthly or quarterly or yearly basis. The end of expedition maintenance is a must.
- Monitor vital signs of Cryogenic Magnetometer weekly to ensure that temperature remains constant within the instrument.
- Clean and lubricate the Flexit and MI5 Icefield tools on a regular basis.
- Bi-annually, change the cryo-cooler compressor. And replace the adsorber in the compressor that is removed from operation so that the compressor is available as a spare.
- Annually, have the ET's do maintenance on the Haskris and ship's chill water recirculating system. This should involve checking for any corrosion or leaks along the water lines.
- Heat the SQUIDS and striplines especially after hard rock legs. Set the I-BIAS on the magnetometer. Make sure the noise level is normal.
VII. END OF EXPEDITION ACTIVITIES
- Perform the end of leg maintenance as listed below.
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- Write the end-of-Expedition lab report, give a copy to the Lab Officer.
- Make sure all data for all paleomagnetic systems are sent to LIMS and DATA1 before the MCSs cut off database access. All non-essential data should be erased from the hard disks of all the computers.
- Pack up equipment being returned for repairs and give the Assistant Lab Officer the following information: IODP inventory number, value, weight, serial number, model number, vendor's name and country of manufacture.
- Give the Lab Officer a list for port purchases, if any.
VIII. PORT CALL – Off Going
- Find the oncoming Technical Staff for your lab and cross over. Make available a copy of your tech report for cross over. Make sure the on-coming staff is aware of any changes made to the lab, procedures, current equipment status, and port purchases if necessary.
- See General JRSO Shipboard Technical Staff SOP.