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# Cold Source Installation and Guide Upgrade

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NCNR is planning for a one year outage to install an upgraded cold neutron source doubling the flux at long wavelengths ($$\lambda$$ > 8 Å).  This new cold source, which will be liquid D2 rather than liquid H2, will improve the performance of most instruments in the neutron guide hall.  A webinar on this activity can be viewed here.

The NCNR will take advantage of this opportunity to upgrade neutron guides, NG5, NG6, and NG7.  The current guides were installed 30 years ago and have 58Ni coatings which were state-of-the-art at the time.  They will be replaced by modern supermirror guides.  To minimize the length of the reactor outage, we will remove portions of NG-5, NG-6, and NG-7 in the guide hall prior to the beginning of the reactor outage.  We expect these guides to be closed for the last time ahead of the reactor outage, after which SPINS and the horizontal sample reflectometer on NG-7 will be permanently retired.

The reactor will restart when the new NG5, NG6, and NG7, have been installed through the confinement wall (D100).  However, the new guides will not have been installed in the guide hall.  We expect that it will take up to a year to replace NG-7 (which serves one of our 30 m SANS instruments) back into operation.  NG-5 and NG-6 will be completed sometime after that.

The new NG5, NG6, and NG7 will be designed to enhance the performance of instruments on these guides.

• NG-7:  Will now serve an upgraded $$\alpha$$-$$\gamma$$ station along with the two interferometers, the test station, and a 30 m SANS instrument.
• NG-6: Will now be curved to serve a significantly enhanced cold neutron imaging station as well as a side position with a monochromatic beam.
• NG-5: Will be designed to serve a substantially improved cold neutron triple axis spectrometer at the end of the guide.

View a presentation giving a summary of the outage activities and upgrades around the new cold source given by Daniel Adler to the ACNS meeting in July 2020.

Created April 7, 2020, Updated February 10, 2023