Assembly 12/14/06 #1 Assembly and Commissioning Paul Huffman

Assembly 12/14/06 #2 Work Package Scope  To bring together the tested components from the individual work packages and integrate them to form a complete apparatus.  To demonstrate completion of the CD4 delivery specifications.

Assembly 12/14/06 #3 Subsystem Integration  The apparatus is unique in that a large fraction of the subsystems must be integrated into the cryogenic vessel. These include: Cryogenic magnetic shields and coil package Measurement cell and high voltage work package 3He polarizer, purifier, and transport work package  The remaining subsystems are less coupled to this vessel and thus have reduced integration concerns.

Assembly 12/14/06 #4 Cryovessel Integration Drives the Schedule  The duration of the integration is dominated by the length and number of times the apparatus must be cooled and tested.  We estimate that each cooldown cycle will take approximately six to eight weeks.  The integration plan attempts to keep the number of cooldown cycles to a minimum.

Assembly 12/14/06 #5 Planning Assumptions  The subsystems arrive at the cryovessel assembly site fully tested.  Integration of the subsystems occurs in a phased approach.  We require the ability to test the 3He transport and the coil package w/o the external magnetic shield.  ORNL is the assembly and commissioning site.  Dedicated cryogenic personnel will be hired by ORNL.

Assembly 12/14/06 #6 Phased Assembly Approach  The subsystems will be incorporated sequentially in the cryovessel. (Order not critical) 1.Measurement cell and high voltage work package 2.Cryogenic magnetic shields and coil package 3.3He polarizer, purifier, and transport work package  This allows us to: balance heat loads with the available cooling powers. test the operation of the supplied components. fully characterize any interactions between subsystems.  Integration of the DAQ subsystem components will occur in parallel as the systems are integrated.

Assembly 12/14/06 #7 High Voltage System and Measurement Cell  Resides primarily inside the 1200-l helium volume.  Contains the high-voltage capacitor and electrodes, the measurement cells and light collection system.

Assembly 12/14/06 #8 Cryogenic Shields and Coil Package  Attached to 4K shields, resides outside of 1200-l helium volume.  Contains a superconducting and ferromagnetic shield and multiple magnetic coils

Assembly 12/14/06 #9 3He Injector and Purifier  Resides in upper section of cryovessel, operates at low temperatures (< 500 mK).  Contains the atomic beam source, purifier, collection volumes, and transport coils and plumbing.

Assembly 12/14/06 #10 Integration Schedule  Schedule (and cost) is dominated by the number of cooldown cycles required for successful commissioning: 4 for insert 3 for coil package 4 for 3He components 5 for integrated tests and commissioning (w/ beam, B-shield)  These estimates are our best guess; it is impossible to know how long it is going to take to diagnose a problem!

Assembly 12/14/06 #11 Non-Cryovessel systems  Integration occurs in parallel  Components include: External magnetic shields Neutron Beam Facilities infrastructure (counting house, power, water, etc.)

Assembly 12/14/06 #12 External Magnetic Shields  Testing and most of the assembly currently not on the critical path.  Estimate four to six weeks just to assemble once!  Very fragile!!  Current schedule minimizes the handling at ORNL.  Not feasible to have shields in place when testing cryovessel.

Assembly 12/14/06 #13 Neutron Beamline  Installation performed by the vendor.  Only last ~2 m of guide on the critical path (mates to cryovessel/B-shields).  Primary constraints are the procurement and the FNPB schedule.

Assembly 12/14/06 #14 Infrastructure  Not on the critical path.  Includes the counting house, electrical, plumbing, and other services.  Schedule assumes larger FNPB external building; a smaller building will delay schedule. Counting House

Assembly 12/14/06 #15 Important Additional Factors  Technician time is significantly more at ORNL than at UT/NCSU.  A lack of on-site cryogenics staff at ORNL will significantly increase the risk and thus increase the number of anticipated cooldowns in this phase of the project.  We have devised a way to perform the magnetic shield assembly and testing at ORNL without removing the cryogenic vessel.

Assembly 12/14/06 #16 CD-4 Requirements  Cryogenic vessel Demonstrated to cool the central detector volume to 500 mK Operated with the magnet coil package in place  Magnet coil package /B 0 < /cm at 77 K *  Four-layer magnetic shield Shielding factor of * * Tests performed offsite

Assembly 12/14/06 #17 CD-4 Requirements (cont.)  Central detector insert High voltage holds 5 kV/cm with a leakage current <10 nA Mean number of photoelectrons from 750 keV of energy deposition is  4 SQUID noise 1 Neutron storage time in similar cell demonstrated to be >100 sec in an independent test

Assembly 12/14/06 #18 CD-4 Requirements (cont.)  3 He services Produces  /cm 3 of  70%-polarized 3 He in the collection volume as seen with a SQUID* Purifier reduces the 3 He concentration to less than 1 part in 10 11* 3 He demonstrated to move between volumes with a time constant of 500 s or less* Valves shown to operate over 500 cycles* Installed in the cryogenic vessel  Neutron guides Flux out/MW  4 x 10 5 n/Å/cm Å with a polarization  70%

Assembly 12/14/06 #19 CD-4 Requirements (Magnetic Shield Scenario)  3 He services Demonstrate 3 He injection, purification, and transport in the assembled apparatus at ORNL  Four-layer magnetic shield Installed at ORNL  Neutron guides Mated to Cryogenic vessel

Assembly 12/14/06 #20 CD-4 Requirements (Completion Scenario)  Operate the high voltage multiplier at 500 mK in the fully assembled apparatus at ORNL to obtain a field of 5kV/cm.  Observe the decaying oscillatory signal from polarized UCN captures on polarized 3 He with a S/N>1  Observe the decaying oscillatory signal from the SQUIDS of the 3 He magnetization with a S/N>1

Assembly 12/14/06 #21 Cost and Schedule ScenarioCD-4 Completion Date CD-4 Approved TPC ORNL Ops 3He installedNew4/6/20136/5/2013$18,427,161$705,367 3He Operational, B-shields in place Early completion with shields in place 1/26/20143/28/2014$18,988,669$275,707 Ready for Data Collection Runs Signals Observed 11/8/20141/8/2015$19,393,340$0

Assembly 12/14/06 #22 Operations Required at ORNL  Construction and integration of the cryovessel at ORNL will require this level of activity: 1 senior cryogenic expert - early postdocs (hired through a university) 1/2 time from S. Penttilä 2 technicians (hired through a university) Cryogenic expertise from the collaboration  Funding is included in the project for the 2 technicians

Assembly 12/14/06 #23 Summary  Duration and costs dominated by the length and number of cooldowns.  Duration can be shorted by shifting parts of the final commissioning into operations.  Cryogenic expertise presently resides at NC State/TUNL.  Personnel hires at ORNL required to proceed with this plan.  NC State will continue to play a leading role in the cryogenics design and implementation.