The n- 3 He Project Christopher Crawford University of Kentucky for the n- 3 He Collaboration n-3He Technical Review ORNL, TN

Outline  Experiment design Physics reaction and observable Experimental setup Installation in the FnPB cave Commissioning and run plan ES&H issues  Collaboration Organization Manpower  WBS subpackages Neutron beamline Magnetic field RF Spin Rotator Target Chamber Preamps Data Acquisition Stand / Alignment  Timeline  Resources P-Division needs

n- 3 He PV asymmetry  Sensitive to isoscalar couplings (I=0) of the Hadronic Weak Interaction  Complementary to NPDGamma (I=1) and p-p scattering (I=0 & 2)  Large asymmetry A = 1.3 x Viviani, et al., PRC 82, (2010), PV observables: Tilley, Weller, Hale, Nucl. Phys. A541, 1 (1992) n n + n n p p p p n n p p n n + p p n n p p n n p p

10 Gauss solenoid RF spin rotator 3 He target / ion chamber supermirror bender polarizer (transverse) FnPB cold neutron guide 3 He Beam Monitor FNPBn- 3 He Experimental setup  longitudinal holding field – suppressed PC nuclear asymmetry A=1.7x10 -6 (Hales) s n  k n x k p suppressed by two small angles  RF spin flipper – negligible spin-dependence of neutron velocity  3 He ion chamber – both target and detector

Assembly in the FnPB cave

Commissioning / run plan 1. Field map in RFSR/Target region 2. Scan beam profile upstream and transfer centroid to crosshairs 3. Scan beam profile downstream 4. Align theodolite to crosshairs 5. Align field probe with theodolite and trim the field to longitudinal 6. Align the position / angle of target with theodolite / autocollimator 7. Tune RSFR / measure polarization 8. Measure physics asymmetry

ES&H Issues  Radiation much lower than from NPDGamma IRR will cover 3 activities: -Front and back beam scans 3 He detector + 6 Li aperture -Polarimetry 3 He polarizer + 3 He monitor -Physics data run 3 He target/detector Beam friendly materials -Aluminum windows transparent to neutrons - 3 He, 6 Li have large cross section with no γ radiation Graduate student will create MCNP model based on NPDG -Will be validated by radiation group  No other safety concerns No HV, Pressure, vacuum, cryogenics, ladders, …

n-3He collaboration  Spokespersons D. Bowman, M. Gericke, C. Crawford  Local Project Manager S. Penttila  Project Engineer Rick Allen  Work Subpackage Leaders M. Gericke Beam monitors G. Greene Polarimetry L. Barrón Magnetic fields C. CrawfordSpin rotator M. Gericke Target chamber J. HamblenPreamplifiers I. NovikovData acquisition D. BowmanAlignment J. Calarco Shielding

Neutron beamline  Scope : FnPB guide, polarizer, beam monitors (existing, NPDG) Beam profile scanners, polarimetry  Status : All equipment exists except aluminum aperture / crosshair Must design shielding to accommodate xy-scanner Must design mount for 3 He analyzer

Magnetic field  Scope : Magnetic field simulations to verity adiabatic spin rotation and uniformity Design and construct longitudinal solenoid and frame Unistructure frame to support RFSR, Target, alignment jigs, mounts on NPDG detector stand.  Status : Conceptual design, preliminary calculations indicate adiabaticity 15 coils, 15 cm apart, 35 cm radius, 150 A turns

Transverse RF spin rotator  Scope: Design and construct RF resonator Driving circuit (use NPDG electronics)  Status: Prototype built and tested, DC current Final design completed Al shell & nylon winding forms machined Need to wind RF coils and map field NPDGamma windings n- 3 He windings

3 He Target / Ion Chamber  Scope : Vacuum chamber, HV + sense wire frames. Gas handling system  Status : Chamber and Macor wire frames delivered Beginning to string wire frames

Preamps  Scope$15k 4 boxes with 32 channels each Design and fabricate circuit, and mechanical enclosure Connector to Target Chamber port and cabling to DAQ module  Status – on critical path Have preliminary design (from NPDG preamps) Must modify circuit for n- 3 He (10x larger signal)

Data Acquisition  Scope: 128 channels of 16/24 bit ADC, > 60 KS/s $25k data acquisition software; RAID storage array $15k  Progress: selected candidate system D-tAcq CQ196CPCI Each card 96 sim. channels + antialias filters + FPGA signal proc. runs Linux on 400MHz XScale processor with gigabit ethernet Inexpensive cPCI chasis used only for power and cooling DAQ software included with hardware – turn-key system awaiting funds to purchase and test system

Alignment  Scope: Aperture / crosshairs for beam scan Support stand and xy-adjustment for theodolite Alignment V-block for trimming B-field Optical system and adjustable mount for target  Progress: Conceptual design

Equipment summary  FnPB / NPDG hardware 3 He beam monitor SM polarizer Beam position monitor Radiation shielding Pb shield walls Beam Stop  New equipment Longitudinal field solenoid mounted on stand Longitudinal RFSF resonator mounted in solenoid 3 He target/ion chamber mounted in solenoid Preamps mounted on target Data acquisition system + RAID storage  NPDG electronics B-field power supply RFSF electronics Trigger electronics SNS / chopper readout Fluxgate magnetometers Computer network

Timeline  Construction of subsystems in parallel Expect to be ready for beam at beginning of cycle Aug 2014 Critical path: preamp design and construction (possibly DAQ) Will stage experiment in EDM building and perform dry run of field map, beam map, and alignment procedures  Milestones Integration of experiment on common stand IRR – begin commissioning phase Begin physics data taking  Runtime 45 days commissioning (all equipment pre-assembled) 15 days PC transverse asymmetry 1.7 x ± 1 x days PV longitudinal asymmetry 1.3 x ± 1 x 10 -8

Resources  All equipment funded except Preamp, DAQ, RAID ($60k) UNAM: (CONACYT $31k) Solenoid and support stand U. Kentucky: (NSF $23k)RF spin rotator U. Manitoba: (NSERC $111k)Target chamber  Minimal utilization of SNS crafts Most equipment mounted on single support structure, staged in the EDM building, craned onto NPDG det. support 3D solid model will be drafted by graduate (Mark McCrea), reviewed by SNS engineer, and incorporated into SNS model MCNP radiation simulation will created by UKy graduate, validated by radiation group Machining will be done at university shops Alignment is relative to beam scan  P-Division operations budget request ($75k) Mainly for Engineering/Radiation support, removal of NPDG See budget spreadsheet for details