IMS-X-ray Image Logger User Guide

March 2019

I. Introduction Introduction

This guide describes the standard operating procedures for the x-ray imager (XMSL).  The system is capable of collecting 2-D x-radiographs on whole round and section half cores.

Theory of Operation

Users should review the X-ray Imager.pptx powerpoint from LeVay, 2019 for background on x-ray radiograph acquisition before operating the system.

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A. Preparing the Instrument

Launching the IMS X-ray Imager application

The IMS XMSL software can be launched from the Windows Start menu or from the desktop Double-click the IMS icon (Figure 91). IMS initializes the instrument.

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Once initialized, the logger is ready to measure the first section.

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Figure 1. IMS Icon.

At launch, the program begins the following initialization process:

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After successful initialization, the main IMS-XMSL window will appear (Figure 102).

Figure 102- XMSL IMS Main Window

Initial Instrument Setup

XMSL Configuration

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

XMSL Instrument General Setup

To open the XMSL instrument setup window (Figure 12), select Instruments > Camera: General Setup from the IMS panel menu (Figure 11).  These settings are related to the detector only.

1. Ensure the values in the window are set as shown in Figure 12.
   1. The instrument X-offset is measured from the home switch to the center pixel of the detector (Figure 13).
   2. This value must be updated should the detector position change or if the home switch on the track is modified.

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

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Figure 12- XMSL Parameters Window

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Figure 13- Position of detector center from the track's home switch

XMSL DAQ Parameters

Prior to collecting x-radiographs on whole rounds or section halves in the XMSL, the user must set the imaging parameters (voltage, exposure, current).  For explanation on how to test exposure parameters prior to imaging, see the Image Utility section. For explanation on how to test image processing parameters, see the Image Process Utility section.

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• Interval: Number of centimeters the core will move between each image.  This value is hardcoded in the IMS software and cannot be changed in this window.  This interval guarantees image overlap, but maximizes system efficiency.
• Width: This is the fixed length of the image produced.  This value is dependent on the detector and hardware setup.  Each image is 15 cm in length, but due to projection, we see less than 15 cm of the core section in the image. For example, with 12 cm of motion, we are seeing 12 cm of core in a 15 cm image.
• Stack: The number of x-radiographs to take at each position.  These images are stacked and averaged to produce the final raw image.  Twenty images is the standard as stacking more images does not appear to improve the image quality further. See Image Stacking section for more explanation.
• Exposure Time: The duration of each exposure in milliseconds.
• X-Ray on Time: Time needed to image a full section keeping the x-rays on between images. Recommended: 300 ms. This time helps to avoid black images.
• kV: X-ray tube voltage.  Maximum voltage for the source is 120 kV. Lowering the voltage while maintaining the number of x-rays penetrating the core (longer exposure or higher current) will increase image contrast.
• mA: X-ray tube current.  Maximum current for the source is 1 mA.   Increasing the current will increase contrast if voltage is kept constant.

Each of the stacked images is taken with the exposure time, kV, and mA set in this window.  To estimate the length of time it takes for each image at specific settings, multiply the exposure time by the number of stacked images.

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Figure 14- XMSL Measurement Editor Window

B. Instrument Calibration

Detector Calibration

Detector calibration should be done at the beginning of the expedition and whenever the exposure settings are changed significantly (integration time especially).  If the detector grid becomes visible in any images, calibrate the detector and reimage the core.

To calibrate the detector select Instruments> Camera: FPD Calibration from the main IMS menu (Figure 11).  The flat panel detector (FPD) calibration utility window will open (Figure 21). The purpose of this utility is to collect images that will be used to perform offset and gain corrections for all images acquired with the FPD.  The calibration process requires two images: Dark (Offset) and White (Gain).

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Figure 21- Detector Calibration user interface window.  From this utility a user may take necessary calibration images and test the corrections prior to applying them to images.

The offset and gain correction are applied to the raw image according to this formula:

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Calibrating the Detector

Dark Image Calibration

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Figure 22 Example of detector grid appearing in image.  If this is noted in an image, immediately stop imaging and recalibrate the detector.

To capture the DARK image:

1.  Select the tab labeled DARK-1 (Figure 21).
   1. The default exposure values are automatically displayed and are the recommend values, but you may set other values. Be aware that the dark saturation (image intensity saturation) must be 7% or lower and you need to capture at least 100 images for stacking. 
   2. Default values are Image stack: 100, kV: 80, mA: 0.7, Integration Time: 1 ms
2. Click the Take DARK Image button.
   1. The X-Ray Image Acquisition window will open (Figure 23).  During acquisition, the image window appears black but you will see values in the histogram and in the image line profile.

Once acquisition is completed, you will be return the FPD Calibration Utility window.

3. Check the saturation value and confirm that is less than 7% (Figure 21). If not, adjust the exposure values and repeat.

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The IMS Control panel (Figure 3): Provides access to utilities/editors via drop-down menus.

Figure 3. Control Panel Drop Down menus.

START button will allow the user to begin measurements. Section Information window (Figure 4) will pop up.

Figure 4. Section Information window.

B. Instrument Calibration

Detector Calibration

Detector calibration should be done at the beginning of the expedition and whenever the exposure settings are changed significantly (integration time especially).  If the detector grid becomes visible in any images, calibrate the detector and reimage the core.

To calibrate the detector select Instruments> Camera: FPD Calibration from the main IMS menu (Figure 3).  The flat panel detector (FPD) calibration utility window will open (Figure 5). The purpose of this utility is to collect images that will be used to perform offset and gain corrections for all images acquired with the FPD.  The calibration process requires two images: Dark (Offset) and White (Gain).

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Figure 5. Detector Calibration user interface window.  From this utility a user may take necessary calibration images and test the corrections prior to applying them to images.

The offset and gain correction are applied to the raw image according to this formula:

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Dark Image Calibration

The DARK image is normally made with the x-rays off to capture the electrical background noise of the detector.  Material used in the detector’s construction causes a grid to imprint on the images (Figure 6); therefore, it is necessary to take the dark image with the x-rays on at minimal level to capture the imprint.

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Figure 6. Example of detector grid appearing in image.  If this is noted in an image, immediately stop imaging and recalibrate the detector.

To capture the DARK image:

1.  Select the tab labeled DARK-1 (Figure 5).
   1. The default exposure values are automatically displayed and are the recommend values, but you may set other values. Be aware that the dark saturation (image intensity saturation) must be 7% or lower and you need to capture at least 100 images for stacking. 
   2. Default values are Image stack: 100, kV: 80, mA: 0.7, Integration Time: 1 ms
2. Click the Take DARK Image button.
   1. The X-Ray Image Acquisition window will open (Figure 7).  During acquisition, the image window appears black but you will see values in the histogram and in the image line profile.

Once acquisition is completed, you will be return the FPD Calibration Utility window.

3. Check the saturation value and confirm that is less than 7% (Figure 3). If not, adjust the exposure values and repeat.

The Dark Max value is used during normal acquisition to warn the user that additional exposure is needed.  Ignoring this warning means that image acquired will have some data clipped at zero.

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Figure 7. Dark Image Acquisition Window

White Image Calibration

The WHITE image is used for the gain correction after the offset correction with the dark image is completed. 

To capture the WHITE image:

1. Select the tab labeled WHITE-2 (Figure 8). 
   1. The default exposure values are automatically displayed and are the recommend values, but you may set other values. Just be aware that the maximum intensity cannot exceed 99%. 
   2. Default values are Image stack: 20,  kV: 112, mA: 1.0, Integration Time: 120 ms
2. Click the Take WHITE Image button.
   1. The X-Ray Image Acquisition window will open (Figure 9).
   2. During acquisition, the image window appears white shading to darker grey on the left and right edges.

Once acquisition is completed, you will be return to the FPD Calibration Utility window.

3. Check the saturation value and confirm that it is in the target range of 94-98%. If not, adjust the exposure values and repeat (Figure 8).

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Figure 8. White Image tab in the detector calibration window

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Figure 9. White Image Acquisition Window

Validating the Calibration

To confirm that the offset and gain calibration have been done correctly, follow this procedure.  Note that this is an optional step, but is a good practice to ensure quality x-radiographs will be produced when imaging core.

1. Select tab TEST-3 (Figure 10)

2. Place a core over the detector and take an image.

a. Adjust the exposure for the material being imaged

3. Once the exposure is completed, you’ll be returned to the FPD Calibration Utility window (Figure 10).

4. Select tab CORRECTED-4 (Figure 11). 

a. The image shown is the raw image with the gain and offset correction applied. 

b. The background on either side of the core should appear as a flat white area. 

c. The shading seen in the WHITE image should be nearly gone.

5. Select the DIFF-5 tab to view the DIFFERENCE image (Figure 11)

a. This image includes the image mask

b. Everything in the image should be black, except the core

c. If the core itself is covered by the mask, then there is an issue with the calibration

6. Select the PROCESSED-6 tab to review the automatically processed image (Figure 12).

a. Evaluate the images.  Do they appear flat grey? Are the images highly eroded?

b, If there is an issue with the processed image, return to the Image Processing utility and adjust the processing parameters.  Then return to the Calibration Utility.

7.  If the Calibration is determined to be acceptable, select Save Calibration Images

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Figure 10. Test Image Tab after selecting take test image

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Figure 11. Corrected Image Tab

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Figure 12. Difference Image Tab

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Figure 13. Processed Image Tab

Saving the Calibration Images

When you have completed acquiring both images and validating the calibration, click Save Calibration Images. These images will be automatically applied to the images. Or select Cancel and revert to the previous calibration images.   The filenames of the DARK and WHITE image files are stored in the I_PI_GOSCAN.ini configuration file.  When the IMS program is initiated, these images are opened and the data is extracted.  If these files are missing you will be notified and will have to complete the calibration process before any images can be acquired.

Other Utility Features

• Saving individual images:  Images shown in the tabs can be saved as TIF image files by selecting Save Image.  A file dialog box will open and the user is prompted to select the location and name of the file.  This does not update the calibration information.
• Source temperature: A graphical temperature display is provided to monitor the temperature of the X-rays source. 

Comments

• During and after acquisition of a new DARK image, the DARK image display will be black. But when the utility first opens and displays the previous image, it appears brighter.  We have confirmed that the data in the image has not been altered from its initial acquisition and have no explanation as to why the display has been lightened.
• Never alter the DARK and WHITE image with other programs.
• The grid pattern is not fully eliminated from the image but is suppressed by the DARK image subtraction.  Under certain conditions and processing parameters it may still be detected in the images.

C. Set Measurement Parameters

a) Instrument Setup

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

XMSL Instrument General Setup

To open the XMSL instrument setup window (Figure 14), select Instruments > Camera: General Setup from the IMS panel menu (Figure 3).  These settings are related to the detector only.

1. Ensure the values in the window are set as shown in Figure 14.
   1. The instrument X-offset is measured from the home switch to the center pixel of the detector (Figure 15).
   2. This value must be updated should the detector position change or if the home switch on the track is modified.
2. Click ACCEPT to save the changes and write them to the configuration file.  Click Cancel to revert to previous values.

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Figure 14. XMSL Parameters Window.

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Figure 15. Position of detector center from the track's home switch.

b) Set Measurement Parameters

Prior to collecting x-radiographs on whole rounds or section halves in the XMSL, the user must set the imaging parameters (voltage, exposure, current).  For explanation on how to test exposure parameters prior to imaging, see the Image Utility section. For explanation on how to test image processing parameters, see the Image Process Utility section.

To open the Measurement Editor (Figure 15), select DAQ > Measurement Editorfrom the IMS panel menu (Figure 3).  This window allows the user to view and adjust the XMSL DAQ parameters.

• Interval: Number of centimeters the core will move between each image.  This value is hardcoded in the IMS software and cannot be changed in this window.  This interval guarantees image overlap, but maximizes system efficiency.
• Width: This is the fixed length of the image produced.  This value is dependent on the detector and hardware setup.  Each image is 15 cm in length, but due to projection, we see less than 15 cm of the core section in the image. For example, with 12 cm of motion, we are seeing 12 cm of core in a 15 cm image.
• Stack: The number of x-radiographs to take at each position.  These images are stacked and averaged to produce the final raw image.  Twenty images is the standard as stacking more images does not appear to improve the image quality further. See Image Stacking section for more explanation.
• Exposure Time: The duration of each exposure in milliseconds.
• X-Ray on Time: Time needed to image a full section keeping the x-rays on between images. Recommended: 300 ms. This time helps to avoid black images.
• kV: X-ray tube voltage.  Maximum voltage for the source is 120 kV. Lowering the voltage while maintaining the number of x-rays penetrating the core (longer exposure or higher current) will increase image contrast.
• mA: X-ray tube current.  Maximum current for the source is 1 mA.   Increasing the current will increase contrast if voltage is kept constant.

Each of the stacked images is taken with the exposure time, kV, and mA set in this window.  To estimate the length of time it takes for each image at specific settings, multiply the exposure time by the number of stacked images.

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Figure 15. XMSL Measurement Editor Window.

D. Preparing Sections

1. Wipe off excess moisture and/or mud from the core liner.
2. Tape any drill holes, when applicable.

Note: All core sections entering the NGR must be completely dry. Any moisture or liquid present will DAMAGE the instrument.

E. Making a Measurement

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Figure 23-Dark Image Acquisition Window

White Image Calibration

The WHITE image is used for the gain correction after the offset correction with the dark image is completed. 

To capture the WHITE image:

1. Select the tab labeled WHITE-2 (Figure 24). 
   1. The default exposure values are automatically displayed and are the recommend values, but you may set other values. Just be aware that the maximum intensity cannot exceed 99%. 
   2. Default values are Image stack: 20,  kV: 112, mA: 1.0, Integration Time: 120 ms
2. Click the Take WHITE Image button.
   1. The X-Ray Image Acquisition window will open (Figure 25).
   2. During acquisition, the image window appears white shading to darker grey on the left and right edges.

Once acquisition is completed, you will be return to the FPD Calibration Utility window.

3. Check the saturation value and confirm that it is in the target range of 94-98%. If not, adjust the exposure values and repeat (Figure 24).

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Figure 24- White Image tab in the detector calibration window

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Figure 25- White Image Acquisition Window

Validating the Calibration

To confirm that the offset and gain calibration have been done correctly, follow this procedure.  Note that this is an optional step, but is a good practice to ensure quality x-radiographs will be produced when imaging core.

1. Select tab TEST-3 (Figure 26)

2. Place a core over the detector and take an image.

a. Adjust the exposure for the material being imaged

3. Once the exposure is completed, you’ll be returned to the FPD Calibration Utility window (Figure 26).

4. Select tab CORRECTED-4 (Figure 27). 

a. The image shown is the raw image with the gain and offset correction applied. 

b. The background on either side of the core should appear as a flat white area. 

c. The shading seen in the WHITE image should be nearly gone.

5. Select the DIFF-5 tab to view the DIFFERENCE image (Figure 28)

a. This image includes the image mask

b. Everything in the image should be black, except the core

c. If the core itself is covered by the mask, then there is an issue with the calibration

6. Select the PROCESSED-6 tab to review the automatically processed image (Figure 29).

a. Evaluate the images.  Do they appear flat grey? Are the images highly eroded?

b, If there is an issue with the processed image, return to the Image Processing utility and adjust the processing parameters.  Then return to the Calibration Utility.

7.  If the Calibration is determined to be acceptable, select Save Calibration Images

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Figure 27- Corrected Image Tab

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Figure 28- Difference Image Tab

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Figure 29- Processed Image Tab

Saving the Calibration Images

When you have completed acquiring both images and validating the calibration, click Save Calibration Images. These images will be automatically applied to the images. Or select Cancel and revert to the previous calibration images.   The filenames of the DARK and WHITE image files are stored in the I_PI_GOSCAN.ini configuration file.  When the IMS program is initiated, these images are opened and the data is extracted.  If these files are missing you will be notified and will have to complete the calibration process before any images can be acquired.

Other Utility Features

• Saving individual images:  Images shown in the tabs can be saved as TIF image files by selecting Save Image.  A file dialog box will open and the user is promted to select the location and name of the file.  This does not update the calibration information.
• Source temperature: A graphical temperature display is provided to monitor the temperature of the X-rays source. 

Comments

• During and after acquisition of a new DARK image, the DARK image display will be black. But when the utility first opens and displays the previous image, it appears brighter.  We have confirmed that the data in the image has not been altered from its initial acquisition and have no explanation as to why the display has been lightened.
• Never alter the DARK and WHITE image with other programs.
• The grid pattern is not fully eliminated from the image but is suppressed by the DARK image subtraction.  Under certain conditions and processing parameters it may still be detected in the images.

C. Set Measurement Parameters

D. Preparing Sections// Preparing Samples

E. Making a Measurement

Starting Measurements

Prior to imaging cores, especially at the start of an expedition, the user must:

1. Perform a detector calibration.  (Detector Calibration Section)
2. Test the exposure parameters in the imaging utility (Imaging Utility Section)
3. Set the exposure parameters in the Measurement Editor (XMSL DAQ Set Measurement Parameters section)
4. Adjust the automatic image processing settings. (Image Processing Section)

Note: Recalibrate the detector if the detector grid pattern becomes visible in the images.

Once these steps are complete, the user may begin imaginimaging.

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1. Click START on the IMS panel (Figure

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1. 2) to open the sample information window (Figures

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1. 16). This is where the user enters the sample ID for a section and initiates the measurement. There are three tabs available on the sample information screen.  Each provides a different method for entering the sample ID information

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• • 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. User the section ID for whole round images and the section half ID for section half images.

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Figure 15- Sample Information Window- Scanner entry (left), LIMS entry (middle), and Manual Entry (right).

Taking X-radiographs

1. Select START on the IMS panel (Figure 11) to open the sample information window (Figure 15).
2. Enter the Sample ID Information

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Figure 16. Sample Information Window- Scanner entry (left), LIMS entry (middle), and Manual Entry (right).

2. Enter the Sample ID Information on the sample information window (Figure 16)

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- 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.

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1. 1. The motion control pusher will move until the section breaks the top of core switch beam.
   2. The x-ray source will ramp up and a window with the x-ray source status will appear (Figure 1617). Once the mA and kV are stable, the window will close and image acquisition will begin.  The user may abort at any time by clicking the Abort button.
      1. Once the top of core is located, the pusher will automatically move the section to the proper location over the detector and begin imaging.  The user interface will have a display as shown in Figure 1718.
      2. The system will automatically take images along the section until the actuator reaches its limit switch, at which time it will return to the home position and the source will ramp down.

Figure 16- 17. X-ray Status Window (left). As the source ramps up, the measured values will update.  X-ray system not ready window (right).  If the source is not ready to ramp up this window will be displayed. Normally, this indicates that a door is open. If the doors are not open, look at the values in the status displays and refer to the vendor’s manual to determine the issue.  As soon as the issue is cleared, this window will close and the x-ray start process will resume.

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Figure 17- 18. IMS Display During Imaging.  Main features of this window include: Abort button, raw image display, imaging parameters display, X-ray source temperature graph, histogram of pixel value and displays of the pixel values along the length and width of the image.

6. The Sample ID information window will reappear on the screen (Figure 1819).

1. 1. Place the Pusher section onto the track.
      1.  The pusher should be an empty liner with tape along the top and bottom edges, not the water core from the WRMSL track. 
      2. Close the load end door.
      3. Select Pusher end sequence in the Sample ID window.  The source will ramp back up and the motion control system will continue to push the section through the x-ray system.

Figure 18- 19. Sample Information Window- Pusher End Sequence View.

When the imaging is complete, IMS will automatically process the raw images and output them to the AUX_DATA folder.  These are not the primary processed images, but are available for quick image evaluation.  For more information on IMS image processing, see the Automatic Image Processing section.

X-Rays OFF

Figure 19 will 20 will be displayed when the X-ray Off command is sent to the CP120.  The window will be displayed until the kV has been confirmed to be at zero.

You will also see this window flash on during X-Ray START when the CP120 fails to respond to the start command.  The X-ray off will reset communications with the CP160 and bring it to a known state which will clear any communication issue.

Figure 19- 20. X-ray Off Status Window

NOTE: During imaging, the user can use the software abort button to end the imaging process and ramp down the source.  The abort button is available when the x-ray source is ramping up and during the imaging process.

If the abort button is used, a dialog window will appear (Figure 2021). Once pressed, imaging will end and the user will need to start imaging the section from the beginning.  Dialog window options are:

Return to Load Position: Actuator returns to the home position. User will need to manually remove core.

OOPS! Please Continue: The software will continue with the measurement.

Stop and Do Nothing:  Actuator will remain in place.  Use this option if the section had jammed in the XMSL or is there is a hardware issue..

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Figure 20- 21. Dialog when after user selects abort during imaging.  The x-ray source will automatically ramp down once abort is selected.  The section in the imager will need to be restarted from the beginning once abort is selected.

F. Evaluating your Measurement

G. IMS Utilities

General Image Utility

The image utility can be found under Instruments > Camera: Image Utility (Figure 11).  This utility is useful for determining the proper voltage, current, and integration (exposure) time for imaging cores.  User can also review the processed images in this utility.

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