NECAT Beamline

The Northeastern Collaborative Access Team (NE-CAT) facility at the Advanced Photon Source at Argonne National Laboratory is managed by Cornell University and consists of seven member institutions:

  • Columbia University
  • Cornell University
  • Harvard University
  • Memorial Sloan-Kettering Cancer Center
  • Massachusetts Institute of Technology
  • Rockefeller University
  • Yale University.

    • Primary funding for this project comes from the National Center for Research Resources (NCRR), a division of the National Institutes of Health (NIH). Additional financial support for NE-CAT comes from the member institutions.

    Status of NE-CAT Construction Project

    May 2006

    24-ID Phase 1 Beam Line Commissioning and User Operations :

    APS accelerator operations were shut down for the month of May for scheduled machine maintenance. Therefore, there is no user activity to report.

    24-ID Phase 2 Fixed-Energy Beam Line :

    Phase 2 installation activities in the radiation enclosure 24-ID-B were able to begin during the May nearly month long APS accelerator shutdown, without impacting the user program of the operational 24-ID Phase 1 beam line.

    The monochromator was surveyed quickly into position. Unfortunately the monochromator footings supplied with the monochromator by Oxford-Danfysik were not appropriate for precise alignment of the monochromator. Therefore, a novel new method was implemented to precisely align the monochromator assembly. The entire monochromator assembly with the feet provided by Oxford-Danfysik was placed on a smooth level steel plate, fixed to the floor in an epoxy pad. A second steel plate which captured the monochromator feet was placed over the fixed steel floor plate with special grease spread between the two plates. A series of eight screw assemblies fixed to the floor place were then used to precisely slide the top plate and consequently the entire monochromator assembly over the fixed floor plate into the desired position. Figure 1 shows the sliding plate assembly before the monochromator was installed. The three square cut outs on the top plate that capture the feet of the monochromator assembly are shown as well as the alignment bolts in the corners used to precisely slide the top plate (and the monochromator) over the fixed bottom plate.

     

    Figure 1. Monochromator Positioning Plate Assembly

    After the monochromator was surveyed into position, the horizontal focusing mirror assembly was moved into the enclosure and aligned, followed by installation of the mirror into the vacuum tank, the photon shutter (between the monochromator and the horizontal focusing mirror), and the remaining beam pipes, vacuum pumps, and ancillary equipment. Figure 2 shows the horizontal focusing mirror being “muscled” into its very tight quarters. Figure 3 shows the mirror being installed in the mirror bending mechanism.

     

     

    Figure 2. Horizontal Focusing Mirror Being Moved into Position

     

    Figure 3. Horizontal Focusing Mirror Being Installed.

    The completed Phase 2 beam line assembly in 24-ID-B is shown in Figure 4. From left to right is shown the horizontal focusing mirror, the photon shutter, and the monochromator.

     

     

    Figure 4. Phase 2 Beam Line Installation in Radiation Enclosure 24-ID-B

    Also during the month of May, the vertical focusing mirror was surveyed into its final position in the 24-ID-E radiation enclosure as shown in Figure 5.

     

    Figure 5. Phase 2 Vertical Focusing Mirror Surveyed into Place in 24-ID-E

    With installation of all the major Phase 2 beam line components in 24-ID-B, commissioning of the Phase 2 beam line was able to commence on the resumption of APS operations on May 30. Remarkably within a few hours of startup on May 30, the “first light” of Phase 2 was obtained, i.e., monochromatic x-rays were obtained from the Phase 2 monochromator using the Si (220) crystal. The beam path was found to be exactly as surveyed. The position stability of the monochromatic beam was, at first examination, stable. However, we noted that pressure bumps from the house chilled water distribution system used to cool the Compton shield did introduce some small motions of the beam. This small instability was eliminated by using a separate recirculation chiller unit for the Compton shield cooling instead of the house chilled water supply.

    Having verified the exact location of the monochromatic beam trajectory, the guillotine shields on the 24-ID-B/E shielding wall can now be machined to accommodate the shielded beam pipe so x-rays can be passed into the 24-ID-E end station enclosure. During the early portion of June, detailed commissioning and calibration studies will be conducted on the monochromator and horizontal focusing mirror in parallel with the Phase 1 beam line user operation. Installation of the end station components are expected to begin during the latter part of June.

     

     
     

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