/
GCR Superconducting Rock Magnetometer (SRM) User Guide

GCR Superconducting Rock Magnetometer (SRM) User Guide

 

Table of Contents:

 

 

 

 

 

 

 

Introduction:

This user guide provides an overview of the IMS-SRM version 10.2 software application for operating the 2G Cryogenic Magnetometer. The SRM software is capable of processing section halves and discrete samples.  

 

Author(s):

Beth Novak

Reviewer(s):

Bill Mills, Katerina Petronotis

Editor(s):

 

Supervisor Approval (Name, Title, Date):

 

Audience:

Laboratory Specialists

Origination date:

2016

Current version:

November 26, 2018

Domain:

Paleomagnetics Lab

System:

SRM

 

Launching the IMS-SRM application

 

The IMS-SRM software can be launched from the Windows Start menu or from a desktop icon (Figure 1).  

Figure 1- SRM Desktop Icon

 


At launch, the program begins the following initialization process:

  • Tests all instrument communications

  • Reloads configuration values

  • Homes the tray in the track

  • Sets the degauss controller to a known state

After successful initialization, the main IMS-SRM window will appear (Figure 2).

Figure 2- SRM IMS Main Window

 

 

 

 


A Quick Introduction to the IMS Program Structure

IMS is a modular program. Individual modules are as follows:

  • INST plug-in: code for each of the instruments

  • MOTION plug-in: code for the motion control system

  • DAQ Engine: code that organizes INST and MOTION plug-ins into a track system

The SRM system, specifically, is built with one INST module (SRM), one MOTION module, and one DAQ Engine module.

The IMS Main User Interface (IMS-UI) calls these modules, instructs them to initialize, and provides a user interface to their functionality.

Each module manages a configuration file that opens the IMS program at the same state it was when previously closed and provides utilities for the user to edit or modify the configuration data and calibration routines.

The four buttons on the IMS-UI window provide access to utilities/editors via dropdown menus as shown in Figure 3.

Figure 3- IMS Control Panel Drop Down Menus

 

 

 


Initial Instrument Setup

SRM Configuration

Configuration values should be set during initial setup and configuration by the paleomagnetics technician or scientist(s). There should be no need to change these values unless the configuration file is corrupted.

SRM Instrument General Setup

To open the SRM instrument setup window (Figure 4), select Instruments > SRM: Setup from the IMS panel menu (Figure 3).

1)     Ensure the values in the window are set as shown in Figure 4.

  • The SQUID constant values are provided by 2G and should not be altered.

  • The response lengths values were determined through extensive testing and should not be altered without prior approval.

  • Once the offset to the SQUIDS is determined, this value should not change unless the track hardware is altered.

  • The text fields are character limited and "Super Conducting Rock Magnetism" for the "Full Name" field exceeds this and will be truncated but causes no known issues.

2)     Click OK to save the changes and write them to the configuration file. Click Cancel to revert to previous values.

Figure 4- SRM Parameters Window

Degauss and Drift Locations Track Setup

This window is used set the distance to the drift measurement locations and the degauss staging positions. To open the Degauss and Drift setup window (Figure 5), select DAQ > Degauss-Drift Locations from the IMS panel menu (Figure 3).

1)     Ensure the values in the window are set as shown in Figure 5.

 

  • These values should never change unless the hardware is replaced or the configuration file is corrupted.

  • These positions will ensure that a 160-cm section is outside of the SQUIDS during zeroing and outside of the degauss region while ramping the coils up and down.

Figure 5- Degauss and Drift Position Configuration Window


Defining Section Half and Discrete Tray Setups

At the beginning of an expedition, or any time the tray is replaced, the scientist(s) or technician must define the two active tray definitions. The program will have in memory the values for just one section half tray and one discrete tray at a time. To open either the Section Tray or Discrete Tray editors, select DAQ > Tray Section Editor or DAQ > Tray Discrete Editor from the IMS panel menu (Figure 3).

  • For section trays, define the distance from the home switch (edge of tray that strikes the home switch) to the location of the top of core (top offset). Set the total tray length (Figure 6).

  • For discrete trays, define the discrete centers (offset from the tray’s edge that strikes the home switch to the center of the position in which the specimens are placed). Set the total tray length (Figure 7). When measuring the background of the discrete tray, only these specific locations will be measured. The user will select which positions are actually used later during sample entry. To remove a discrete center, right click on the position and select Delete element. 

Making changes to the tray settings will invalidate the background measurement. The user will be given a warning when they try to start a measurement.  A new background will be needed before a measurement can be completed.

Figure 6- Section Tray Editor Window

 

Figure 7- Discrete Tray Editor Window

 

Figure 8- Warning window when current tray settings and

last background measurement do not match

 

 

 

Setting Up for a Measurement

 

Prior to measuring section halves or discrete samples in the SRM the user must:

  • Set the measurement interval

  • Take a background measurement of the empty tray

  • Create or select a measurement sequence

  • Create or select a sample type preset

Setting the Measurement Parameters

To open the Measurement Editor (Figure 9), select DAQ > Measurement Editor from the IMS panel menu (Figure 3).

This window allows the user to view and adjust the SRM DAQ Parameters. The current settings are shown in the bottom left hand corner of the window.

  • Interval: Interval in cm between measurements. This is only valid for SECTION HALF measurements. The measurement interval can range from 0.1 to 20 cm. The most common measurement intervals used are 2.5 cm, 5 cm, and 10 cm.

  • Average: The number of measurements to take at each position. The measurements will be averaged and the mean will be written to the data files.

  • Leader/Trailer Length: The distance in cm that is measured before and after the section. This is used in deconvolution processing.

Measurement Speed: User selects slow or fast speed, which determines the settling time and data filter.  Slow speed reduces noise while fast speed completes measurements more quickly.  Slow speed is recommended.

FLUX Alarm Threshold: The flux count value above which the SRM program will trigger a Flux Jump Alarm. Flux counts between the positive and negative threshold value will not trigger the alarm.

Figure 9- Measurement Editor Window

 

The SRM software is designed to check if the current measurement interval matches the current background tray measurement interval. If the intervals differ, the user must complete a new background measurement. The software will not allow the user to begin a measurement if the values differ. If a change is made, the user may see a red indicator next to DAQ Valid, indicating a new background measurement is necessary (Figure 10).

 

Figure 10- DAQ Invalid Warning in Measurement Editor Window



Click ACCEPT to exit the Measurement Editor Window once the parameters are set. Select Revert to return to the previous values or select Cancel to leave the window without saving any changes.

Measuring Tray Backgrounds

To measure the background of a section or discrete tray:

1)     Select Instruments > SRM: Section Background or Instruments > SRM: Discrete Background (depending on the tray type used)(Figure 11) from the IMS panel menu (Figure 3).

  • The default action for the tray background measurement is to demagnetize the tray and then to measure the empty tray.

  • The user may adjust the demagnetization level (maximum of 80 mT) or choose to measure without demagnetizing the tray. The demagnetization level setting box will be disabled when the user has selected a background only (no demagnetization) measurement.

Figure 11- Section Tray and Discrete Tray Background Windows

 

2)     Click START to begin the background measurement process.

3)    When the process is complete the user will be prompted to ACCEPT and save background data (Figure 12).  If the background data looks suspect (high values or peaks), select CANCEL. 

 

If the data are saved, a new background tray file will be written. The most recent tray measured for each type (section or discrete) will be kept in memory.

These background data will be applied to all subsequent measurements of the same type. 

Figure 12- Background Confirmation Window

 

 


Creating a Measurement Sequence

1)    Open the Sequence Editor (Figure 13) by selecting DAQ > Sequence Editor from the IMS panel menu (Figure 3).

 

Figure 13- Sequence Editor Window


2)     Select a sequence action on the left side of the window. In-line and off-line treatments are mutually exclusive. Once a treatment type is selected, the other treatment type will be disabled.

  • Measure only should be used to make an NRM measurement.

  • In-line AF Demag allows users to assign a degaussing step with a field ranging from 1 to 80 mT.

  • Off-line Treatment will place an “off-line treatment” into the sequence list.  Accept the sequence.  A dialog box will be triggered (Figure 14) during the measurement process prompting the user to perform an offline treatment. The user may enter the type of offline treatment and comments regarding the treatment. The types of treatments available are shown in Figure 14. Click Continue Sequence to continue with the measurement and Abort to end the sequence.

Figure 14- Offline Treatment Window


3)     Users may copy an existing sequence from a file by clicking the Copy From File button.

  • A new window with a list of existing sequences will be displayed (Figure 15).

  • Select an existing sequence and press the Copy button.

  • Once selected, a sequence will be displayed in the sequence action list and the user may edit the sequence (Figure 13).

Figure 15- Copy Sequence File Window


4)     Click Add to List to place a new step into the sequence action list.

  • In-line AF Demag steps will be automatically ordered by increasing value.

  • Each in-line AF Demag step automatically has a measurement step.

5)     Once the list is completed, click Ok Save and name the sequence

  • The sequence will be saved with a new name or the user may save over an existing sequence.

Defining the Sample Presets

The data calculations for the SRM are volume dependent and therefore it is necessary to assign the appropriate shape and volume to the sample prior to measurements. In the sample preset editor window the user can set the sample shape, section half, and the orientation of the sample. The volume used for each shape is displayed, and in some cases, may be edited.

Create Sample Presets

1)     To open the Sample Preset Editor (Figure 16), select DAQ > Sample Preset Editor from the IMS panel menu (Figure 3).

2)     Select a sample shape from the left hand column.

Section Half-Piston and Discrete J-cube are the most commonly used presets.

3)     Note the volume or area values.

  1. The Section Half-Piston, Section Half-Rotary, Discrete IODP, Discrete J-Cube, and U-channel sample shapes have fixed volumes.

  2. For all other sample shapes the user may edit the actual volume/area value. Only one value may be assigned to a shape. Always check the volume/area value.

  3. For Section Halves, Select Section Half-Piston or Section Half-Rotary (Figure 16):

  • Verify the area. Piston cores should be 17.50 cm2 and Rotary cores should be 13.40 cm2.

4)    Select the section half at the bottom of the window. In most cases this should be ARCHIVE for section halves.

Figure 16- Sample Preset Editor Window: Section Half View


5)     For Discrete Specimens, Select a Discrete Cube shape and orientation (Figure 17).

  • Shapes include: Discrete IODP-Cube, Discrete J-Cube, Discrete Mini Core, and Discrete Other.

  • Orientation includes Face Orientation and Arrow Orientation:

  • Face Orientation refers to which direction the face of the cube with the arrow is facing relative to the SRM (i.e., Top means the arrow is on the top of the cube, left means that the arrow is on the left side of the cube when looking toward the SRM).

  • Arrow Orientation refers to the direction the arrow is facing (i.e., Into means the arrow is pointing into the SRM, Right means the arrow is pointing to the right when looking toward the SRM).

The arrow in the diagrams indicates the arrow or hatch mark placed on the split face of the core section during sampling. The arrow points to the top of the core.

  • There are 24 possible cube positions. During Expedition 318 it was determined that three positions were sufficient for measuring discrete cubes. These three orientations were: Top-Into, Top-Right, and Away-Up.

6)     Select the face orientation and arrow orientation that the cube will be placed in the tray. Orientations are relative to the SRM when the user is looking from the load zone toward the SQUIDS.

Place the cube into the tray so that the cube arrow matches the preset display.

7)    Select the section half at the bottom of the window. In most cases this should be WORKING for discrete samples.

Figure 17- Sample Preset Editor: Discrete Sample View


Save the Sample Preset

1)     Check the white square box on the right side of the screen (Figure 16 and Figure 17).

2)     Click on one of the six sample preset buttons and a window will appear (Figure 18).

 

Figure 18- Edit Preset Window. Name a new preset, update an existing preset, or disable a preset button.

3)     Enter a name for the button in the NAME field.

  • Include the orientation in the name (i.e., Archive, Working, Top-Away, etc.).

  • For section halves, include the type of core (i.e., Rotary or Piston).

4)     Select UPDATE BUTTON to save the preset.

  • Disable Button will clear any preset already saved to this button.

  • Cancel edit will close the edit preset button name window without making any changes.

5)     The preset name should be visible on the right hand side of the page. Figure 17 has two presets assigned: Archive_SHLF_Piston and Archive_SHLF-Rotary.

To review what has been assigned to a preset button, click the preset button once. The screen image will update to show the current preset.

To clear a preset

1)     From a single button:

  • Open the button as if to name a preset.

  • Select Disable Button.

 

2)     For all six buttons:

  • Select the Clear All Presets button.

  • User will be asked to confirm the deletion (Figure 19).

Figure 19- Clear Presets Confirmation Window

3)     Select OK to exit the preset editor

 

 

 

Starting Measurements

Sample Information Window

Click START on the IMS panel (Figure 2) to open the sample information window (Figure 20–Figure 26). This is where the user enters the sample ID for a section or discrete sample and initiates the measurement.

There are four available tabs on the sample information screen. The first 3 tabs allow the user to enter sample identification information using 3 different methods. The fourth tab allows the user to select a measurement sequence.

Sample Entry Tabs

  • Scanner: Scan the IODP barcode to enter the sample’s Text ID and Label ID values.

  • LIMS: Select expedition, site, hole, core, and section values from a series of list boxes that are populated with data from the LIMS database.

  • Manual: Manually enter the sample’s Text ID and Label ID values and a length. The name fields will accept any name, so the user must be careful to enter the name properly. If the name is incorrect a file will be created, but it may not upload properly. 

Measurement Sequence Tab

The user can select a premade measurement sequence in the Measurement Sequence tab (Figure 20). The last used measurement sequence will remain in memory and is displayed at the bottom of the sample information window. If the sequence displayed is correct, the user does not need to utilize the measurement sequence tab.

Figure 20- Sample Information Window: Measurement Sequence Selection

The user can select a premade measurement sequence in the Measurement Sequence tab (Figure 20). The last used measurement sequence will remain in memory and is displayed at the bottom of the sample information window. If the sequence displayed is correct, the user does not need to utilize the measurement sequence tab.

  • Click on sequence name in the Measurement Sequence Files list to start a sequence with the first step.

  • To begin at a specific step within a sequence, click on a step in the sequence action list and highlight it blue. Be careful! If a demagnetization step is highlighted blue in the sequence action list, the demagnetization process will start once the MEASURE button is pressed. As of November 2018 this feature does not work. 


Figure 21- Sample Information Window: Section Half Scanner Sample Entry

Section Half Sample Entry


1)     Select START on the IMS panel (Figure 2) to open the sample information window (Figure 21).

2)     Select a measurement sequence in the Measurement Sequence tab (Figure 20). The sequence may already be selected and displayed in the lower portion of the window.

3)     Select the appropriate sample type and orientation preset on the left side of the screen.

4)     Enter the Sample ID Information

  • Scanner mode: Place cursor in the scan box; scan the section half label from the end cap (Figure 21).

  • LIMS mode: Select a section using the hierarchy columns (Figure 22). Only the sections/cores that match your preset will display (e.g., if you select an archive half section preset, only archive half sections will be displayed).

  • Manual entry mode: Type in the sample label ID (i.e., 362-U1480A-1H-1-A) and LIMS Text ID (i.e., SHLF7851761) and length of section (Figure 23).

    • Any entry will be accepted, but that does not guarantee the data will upload. The Text ID information must match an actual section in order for the data to upload.

    • Select USE ME to update the IDs and enable the MEASURE button.

5)     Check that the displayed length of the section matches the section length. 

  • To override the section length, first scan the label on the Scan tab and then select the Manual tab. The Sample ID and Text ID values will be copied. Enter the length in the USER Length numeric control and then click the USE ME button.

6)    Click MEASURE.

Figure 22- Sample Information Window: Section Half

Figure 23- Sample Information Window: Section Half Manual Entry

 

Discrete Sample Entry

1)     Click START on the IMS Control Window (Figure 2) to open the sample information window (Figure 21).

2)     Select the appropriate discrete sample type and orientation preset on the left side of the screen.

3)     Select a measurement sequence in the Measurement Sequence tab (Figure 20).

4)     Enter the Sample ID Information:

  • Scanner mode: Place cursor in the scan box and scan the discrete cube label (Figure 24). The sample will be immediately assigned to the tray position highlighted on the right side of the screen.

  • LIMS mode: Use the hierarchy selection columns to select a discrete sample (Figure 25). You must select a sample from the Discrete Sample list box before you can assign it to a tray position. Double click on the Tray Position list to assign it to a tray position.

    • Samples can be listed by core or section and filtered by sample type and/or code. See the special features: LIMS Filter Section of this guide for further information.

    • Remember that only samples that match the preset’s sample source (Archive or Working) will be displayed. For example, if you select an archive preset then any samples from the working half will not be displayed.

  • Manual entry mode: Type in the sample label ID (i.e., 362-U1480B-1H-2-W 117/119-PMAG) and LIMS Text ID (i.e., CUBE7990351) (Figure 26). Anything will be accepted, but that does not guarantee the data will upload. The ID information must match an actual sample in order for the data to upload.

    • Click the USE ME button to use the ID information. Double click on a Tray Position to assign the ID information to that tray position.

    • The Sample ID and LIMS ID should be displayed below the manual entry tab as seen in Figure 26.

5)    Click MEASURE to begin measuring the discrete samples

Figure 24- Sample Information Window: Discrete Scanner Entry

Figure 25- Sample Information Window: Discrete LIMS Entry

Figure 26- Sample Information Window: Discrete Manual Entry

Offline treatment

The SRM aboard the JR is limited to AF demagnetization up to 80 mT. However, due to a coil overheating incident, it is strongly recommended not to use a field higher than 50 mT. In some instances, scientists may need to conduct analyses on discrete samples which require a field higher than 50 mT, ARM or IRM. Field higher than 50 mT and up to 200 mT can be applied with the D-Tech degausser in the lab (DTech AF Demagnetizer User Guide). ARM can be imparted with the D-Tech. IRM can be imparted with the two impulse magnetizers present in the lab.

As of October 28, 2022, the IMS-SRM code of the SRM does not include off line treatment. Therefore, when measuring the samples with the SRM the .DSC file, which is read by the uploader MUT2, will contain the information "NRM" in the file name and in the treatment type.

In order to upload the data to LIMS with accurate information, a few steps need to be taken by the scientists/technician.

  1. In the .DSC file, change treatment_type = NRM to treatment_type= IN-LINE AF DEMAG

  2. In the .DSC file, change treatment_value = 0 to treatment_value = "value of AF field" (step 1 in Figure A1 below)

  3. Rename the file by changing _NRM to _INAFvalue and save it (step 2 in Figure A1 below).

  4. Upload with MUT2. The LORE report will have the information as if the sample was measured with the SRM with an "in-line" treatment (Figure A2)

Figure A1. Changing Treatment Type and Treatment Value for an offline treatment in the .DSC file

Figure A2. Corresponding LORE report as if the offline treatment is "in-line"

 

An alternative to renaming entries and files, the scientists/technician have the possibility to enter codes in the Comment box of the sample information on IMS-SIRM (Figure 26). To keep track of treatment steps in the LIMS download files for offline treatment of discrete samples, the scientists/technician have to use a controlled vocabulary by entering the following codes (in purple) for the offline treatments:

  • for NRM: NRM

  • for AF demagnetization at 60 mT (for example): AF:60