Magnet schedule Recent timeline Magnet tests of small

Magnet schedule Recent timeline: Magnet tests of small system in September 2017, see Jason’s talk Since then, some progress with fabrication of parts, and some setbacks (needed to find new gold plating shop, needed extension of winding machine more problematic than thought). New dewar concept (again: See Jason’s talk). New timeline: Dec Week # 49 Receipt of upper cryostat, shield Wind/Cast TOF' Wind UDET Cast UDET Wind UDET' Bore tube electropolishing Bore tube gold plating Overall assembly Prepare for test Full system test Shipment 50 51 Jan 52 1 2 3 Feb 4 5 6 7 Mar 8 9 10 11 Apr 12 13 14 1

Project critical path Project schedule and critical path is always on http: //nab. phys. virginia. edu/restricted/project/index. html, and is kept up-to-date quarterly. Last update not complete on website; this update will say Magnet arrives mid-April. Follow installation schedule: A. Mid April to Mid June: Magnet acceptance test on-site B. Mid June to end of July: Installation of magnet in passive shield. C. August: Casemate Modifications, platform installation: Needed: AFP Spin flipper, beam shutter, collimators, neutron beam windows, internal collimators in magnet, neutron beam vacuum system, pumps and vacuum gauges, some of experiment control system D. September: Field mapping: Needed: hall probe holder, insert for precise movement of probe E. ½ October: Installation of Detectors and Electronics Needed: detectors (at least one? ), electronics, radioactive source insertion system, radiation shields, internal electrodes F. ½ October: Verification of UHV conditions G. November-December: HV and detector tests Need: Most of experiment control system, online analysis H. January: IRR 2

Alternate critical path It seems well possible that the project’s critical path will be determined by the detector. This may be desired up to a point, but we cannot do all desirable detector tests in the project. One of the big tasks today is to discuss detector tests. We should keep in mind the timeline: 1. We should ship one detector mount (with detector and DAQ system) to Manitoba end of April, and that already means that we install only one detector in Nab during project. THIS IS IN SOME CONFLICT WITH MARK’S SCHEDULE FOR LOS ALAMOS 2. We should ship second detector mount to ORNL in September. This is just when it is needed for installation; no previous tests foreseen. (See Mark’s and Leah’s talk for more info on timeline) Open: • Should we ship DAQ system to Manitoba? Where and when do we test how the two system talk to each other? • What does Manitoba need to get the proton detector running; can Manitoba support development at LANL, in part to get experience? • Who else can help testing / assembly at LANL? • Residual gas level in Manitoba. 3

Nab beyond the project: Commissioning Obviously, we will take neutron data, and optimize detector, electronic, analysis Measurement with in-situ radioactive source (or variant: times source) Other auxiliary measurements with Nab detectors inside or outside Nab Background studies (Ge-detector) (to understand its origin, composition, time structure) • Neutron beam profile measurement • Neutron beam polarization measurement • • Need to discuss: So far, only viable idea to blind analysis is ACORN’s idea: Blind neutron beam polarization measurement, use AFP spin flipper, analyze only one state. PLUS: Remainder of analysis largely independent of the outcome Neutron beam polarization really not known at the level we care MINUS: Analysis of spectrometer properties not fully independent of polarization (angular distribution of decay particles changes) Hard to keep result secret and verify quality of polarization measurement at the same time. 4