I. Introduction

This guide describes the standard operating procedures for the X-Ray imager (XSCAN). The system is capable of collecting linescan X-radiographs on whole round and section half cores. Furthermore, the source and detector can be rotated around the core material for linescans with different view angles.

Theory of Operation

Users should review the X-Ray Methods and Theory Powerpoint from B. LeVay, 2019 for background on X-Ray radiograph acquisition before operating the system.

Hardware

The IODP X-Ray scanner is composed of a 210W, 160 kV, 1.3 mA constant potential X-Ray source and a linescan detector. The source is a Spellman XRBD 160PN210 Monoblock X-Ray generator with a 0.5 mm focal spot. The beam fan angle is 90 x 12 degrees which is distanced approximately 36 cm from the source. The detector is a Hamamatsu C12300-321 composed of a CCD sensor with a ~22 cm field of view utilizing time-delayed integration (TDI) and a resolution of 48 microns per pixel. (Add the corresponding documentation on Confluence: Hamamatsu manual, Spellman XRB)

Shielding

The shielding consists of several complimentary designs. The primary shield (Figure 1) houses the X-Ray source and detector. It is constructed of 3D-printed ABS plastic with hollow walls that are filled with Tungsten powder. The base of the primary shield (under the detector) is a solid piece of 1-cm thick Tungsten plate to block the primary X-Ray beam.  X-Ray scatter is shielded by 2mm lead equivalent leaded vinyl or leaded acrylic panels on the sides, ends, top and bottom of the logger (Figure 2). The leaded acrylic provides a view of the inside of the logger while it operates. The hatches that allow insertion of core material on either end of the logger are also shielded with solid Tungsten plates.

 Figure 1: Primary shield top and bottom halves, the latter shows the tungsten powder filling and solid tungsten plate used in the first design of the XSCAN.

Figure 2: Leaded acrylic and leaded vinyl shielding panels

Safety Systems

The XSCAN imager has multiple safety systems in place to ensure a user does not operate the system in a radiologically unsafe manner. Never attempt to operate the X-Ray source without the proper shielding in place! The safety subsystems include:

• Colored light status indicators (AKA Patlite tower) (Figure 5)
• X-rays ON amber lights on two corners (Figure 3)
• Shutter position sensors
• Door electronic locks (Figure 6)
• X-ray source interlock
• Emergency Stop Switch (motion and X-ray abort) (Figure 7)
• X-rays auto-off after a user-selectable period

These components are wired into one fail safe system controlled by a National Instruments cRIO-9053 unit.

Figure 3: X-Ray emitting lights (lit=ON) on two corners of the XSCAN

Failsafe Circuitry

In order to generate X-Rays, a series of safety switches and shutter positions must be verified to enable the generation of X-Rays.  Certain switches or sensors are operated electrically, others use pneumatics.

Figure 4 shows the failsafe circuit and the safety switches involved.  All switches must be verified before the software command to generate X-Rays will be performed.

Figure 4: Fail safe circuit schematic. 

Visual Indicators

A multi-color tower light mounted horizontally on the top corner of the logger acts as a visual indicator of the safety system and X-Ray status.  It has four segments that reflect specific safety subsystems of the logger plus one for the measurement phase at the time (Figure 5).

• X-Ray source:
  • Amber: source is in use, X-Rays are emitted
  • Green: source is ON, but there is no X-ray emission
  • Light OFF: source is OFF
• Shutter light indicator:
  • Amber: shutter is open
  • Green: shutter is closed – safe to open doors
  • Light OFF: shutter is disabled
• Door light indicators:
  • Amber: doors are latched and/or unsafe to open
  • Green: doors are unlatched, safe to open
• IMS measurement operations status colors:
  • Purple – initialized
  • Green – idle
  • Blue – translational move of the camera
  • Sky blue – rotational move of the camera
  • Amber – image in progress
  • Off – quit IMS

Figure 5: Multi-section Patlite tower mounted horizontally at the top of the logger.  These lights act as visual indicators of measurement operations, door(s), and X-Ray status.

The Table 1 below illustrates the status combinations:

Table 1. Different Patlite status indicator combinations

Door Switches

Electronically-controlled safety locks have been installed on both the forward and aft doors.  If either of these doors are open at the beginning of imaging, calibration or seasoning the c-RIO will disallow the process and warn the user about it. There are also indicator lights on the door lock electronics (Figure 6).  Note that a lit red indicator means that the door is unlocked and can be opened.

Image Added

Figure 6: Electronic safety lock on the logger door

Emergency Stop Switch

There are two main Emergency Stop switches installed on the XSCAN, one for each source.

• Main (in use) source (name or reference number S/N: 135769488-A00001)

An emergency stop (e-stop) switch is located on the front side of the XSCAN (Figure 7).  When activated, i.e., the user hits the button, the e-stop switch cuts two circuits.  One circuit runs straight to the source power supply and one circuit runs through the cRIO with the safety circuit. The e-stop switch opens the interlock on the XRB and the X rays go OFF. It also kills the MDrive and will immediately stop all motion.

picture here of Figure 7

Figure 7: X-ray logger Emergency Shut Off Switch. {replace with image of final XSCAN placement if different}

• Spare source (name or reference number)

The e-stop for the spare source is located near the spare source at the bottom of the XSCAN 

Image Added

Figure 8: Emergency Shut Off Switch of the spare source

II. Procedures

III. Uploading Data to LIMS

IV. Appendix

A.1. Health, Safety and Environment

A.2. Maintenance and Troubleshooting

V. Credits

VI. LIMS Component Table

VII. Archived Version

Cleaning tube