1. The n- 3 He Experiment Christopher Crawford University of Kentucky for the n- 3 He Collaboration FnPB PRAC ORNL, TN 2013-01-23

2. Outline  Physics Reaction & observable EFT calculation Statistical sensitivity Systematic effects  Experimental design Experimental setup Installation at FnPB Commission & run plan ES&H issues  Collaboration Organization / Manpower  WBS subpackages Neutron beamline Stand / Alignment Magnetic field RF Spin Rotator Target Chamber Preamps Data Acquisition  Project Timeline Resources

3. 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 = 1.15 x 10 -7 Viviani, et al., PRC 82, 044001 (2010), PV observables: 19.815 20.578 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

4. Theoretical calculations – progress  Gerry Hale (LANL) PC A y ( 90 ) = -1.7 +/- 0.3 x 10 -6 R matrix calculation of PC asymmetry, nuclear structure, and resonance properties  Michele Viviani et al. (INFN Pisa)PV A = -(.248 –.944)£10 -7 full 4-body calculation of scattering wave function -Kohn variational method with hyperspherical functions -No parity mixing in this step: J π = 0 +, 0 -, 1 +, 1 - -Tested against n- 3 He scattering lengths evaluation of weak matrix elements -In terms of DDH potential Viviani, Schiavilla, Girlanda, Kievsky, Marcucci, PRC 82, 044001 (2010) Girlanda, Kievsky, Marcucci, Pastore, Schiavilla, Viviani, PRL 105 232502 (2010)  Vladimir Gudkov (USC)PV A = -(1 – 4)£10 -7 PV reaction theory Gudkov, PRC 82, 065502 (2010)  Michele Viviani et al. (INFN Pisa)PV V NN EFT, a 0 – a 5 Viviani, PAVI (2011), preliminary

5. Sensitivity matrix for few-body reactions Contribution: 1.15 0.087 1.55 – -.002 -0.47 –

6. EFT NN potential revisited to NNLO  Viviani et al., preliminary (PAVI 11) (a) Q 0 h 1 π g π (r) (CT) Q 1 C 1,2,3,4,5 Z(r) (b,c) Q 2 zero (e,h) Q 2 renorm./absorb in h 1 π (d), Q 2 h 1 π+ C 3 (triangle) L(r) (f,g,g’) Q 2 h 1 π (box) H(r)+L(r) A z n3He (prelim) using N3LO (Emtem & Macheleidt) + 3N N2LO (Navratil) Λ = 500: a 0 =-0.15 a 1 =.026 a 2 =.021 a 3 =0.11 a 4 =-.043 a 5 =-.0022

7. 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

8. MC Simulations  Two independent simulations: 1.a code based on GEANT4 2.a stand-alone code including wire correlations Ionization at each wire plane averaged over: neutron beam phase space capture distribution ionization distribution  (z) uniform distribution of proton angles cos  n ¢k p /k p Used to calculate detector efficiency (effective statistics / neutron flux)

9. MC Simulations – Results  Majority of neutron captures occur at the very front of chamber Self-normalization of beam fluctuations Reduction in sensitivity to A

10. Runtime estimate for n-3He at FnPB  N = 1.5x10 10 n/s flux (chopped) x 10 7 s (116 days)  P = 96.2%neutron polarization   d = 6detector efficiency  15% measurement in 1 beam cycle (without contingency), assuming A z = 1.15 x 10 -7 = 1.6 x 10 -8

11. Systematics  Beam fluctuations, polarization, RFSF efficiency:  k n r ~ 10 -5 small for cold neutrons  PC asymmetries minimized with longitudinal polarization  Alignment of field, beam, and chamber: 10 mrad achievable  Unlike NPDG, NDTG: insensitive to gammas (only Compton electrons)

12. Assembly in the FnPB cave

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

14. 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, …

15. 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

16. 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

17. 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

18. Magnetic field  Scope : Magnetic field simulations to verity adiabatic spin rotation and uniformity Design and construct longitudinal solenoid and frame Map fields at UNAM before delivery to SNS  Status : Conceptual design, preliminary calculations indicate adiabaticity 15 coils, 15 cm apart, 35 cm radius, 150 A turns

19. Transverse RF spin rotator  Resonant RF spin rotator P-N Seo et al., Phys. Rev. S.T. Accel. Beam 11, 084701 (2008)  Properties suitable for n- 3 He expt. Transverse horizontal RF B-field Longitudinal or transverse flipping No fringe field - 100% efficiency Real, not eddy currents along outside minimizes RF leaked outside SR Doesn’t affect neutron velocity Compact geometry Matched to the driver electronics of the NPDGamma spin flipper  Construction Development in parallel with similar design for nEDM neutron guide field Few-winding prototype built at UKy; Production RFSF being built now field lines end cap windings NPDGamma windings n- 3 He windings

20. Inner / outer coil design  Windings calculated using scalar potential Uniform transverse RF field inside Zero leakage field enforced by B.C.’s Copper wires run along equipotentials 1.Inner region: 2.Intermediate: 3.Outer region:  4:1 inside / outside winding ratio By choosing appropriate radii Perfect cos theta windings inside & out 48 inner loops of 18 AWG wire

21. Electrical specifications – compatible with NPDG  Holding field:  Resonant frequency:  Inductance:4.5 mH  Capacitance:7.5 nF  Resistance:5.1 Ω  Maximum voltage:  Stored energy:  Dissipated power:  Quality factor: Q=151  R&D: test 3 winding patterns with same field in high-frequency limit INNER INNER/OUTER OUTER easiest to wind no eddy currents no copper in beam

22. Progress & Schedule  Design completed in 2011  Resonator machined except wire grooves  March 2013: Finish machining  May 2013: Finish winding  September 2013: RF field map  November 2013: Test with preamps and DAQ system

23. Target Chamber  Chamber design finished in 2010 delivered to U. of Manitoba, Fall 2010  All aluminum except for the knife edges. 4 feedthrough ports (200 readout channels) 2 HV ports + 2 gas inlets/outlets 12 inch Conflat aluminum windows (0.9 mm thick).

24. Frame Design and Construction  Chamber frame design finished in 2012  Received 50 Macor wire frames (up to 25 signal and 25 HV) $30K  Final feature machining planned for early this year at UT shop.  Platinum-Gold thick film wire solder pads on Macor to be completed early this year by Hybrid Sources Inc..

25. Frame Assembly and Signal Readout  The frame mounting structure is designed pieces will be ordered in the spring  Two options for frame mounting: Mount into exit flange with threaded rods Insert into existing exit window flange  Signal readout via circuit board traces Single HV connections Guide wires to feedthroughs with PMT- inspired stand-offs and ceramic beads

26. Target Chamber Assembly Schedule  February 2013: Have test frame finished by Hybrid Sources and verify measurements.  March 2013: Complete feature machining at UT shop.  April 2013: Order remaining parts for frame assembly and feedthroughs.  June-July 2013: Completed solder pad deposition by Hybrid Sources.  October 2013: Complete chamber assembly  December 2013: Test with RFSF and DAQ

27. Preamps  Scope 4 boxes with 32 channels each$41k Design and fabricate circuit, and mechanical enclosure Connector to Target Chamber port and cabling to DAQ module  Status – on critical path – need resources soon! Have preliminary design (from NPDG preamps) Must modify circuit for n- 3 He (high channel density, 10x larger signal)

28. Data Acquisition  Scope: 128 channels of 16/24 bit ADC, > 60 KS/s $51k data acquisition software; RAID storage array $25k  Status – need resources soon to begin development and testing! selected candidate system D-tAcq CQ196CPCI-96-500 Each card 96 sim. channels + antialiasing filters + FPGA signal proc. runs Linux on 400MHz XScale processor with Gigabit Ethernet Inexpensive cPCI chassis used only for power and cooling DAQ software included with hardware – turn-key system awaiting funds to purchase and test system

29. 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

30. Timeline  Construction of subsystems in parallel Will 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 See Gantt chart for details  Milestones 2014-04-21 Begin assembly and testing in EDM building 2014-07-18 Begin installation in FnPB cave 2014-10-27 IRR – begin commissioning phase 2015-02-?? Physics data taking at beginning of beam cycle  Time budget 76 days commissioning (all equipment pre-assembled) 15 days PC transverse asymmetry 1.7 x 10 -6 ± 0.5 x 10 -7 116 days PV longitudinal asymmetry 1.15 x 10 -7 ± 1.6 x 10 -8

31. Resources  All equipment funded except Preamp, DAQ, RAID ($117k) 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  Total P-Division operations budget request ($200k) $117k for DAQ + $83k for Engineering/Radiation/Craft support See budget spreadsheet for details

32. Standing in between elephants