The n3 He Project Christopher Crawford University of

The n-3 He Project Christopher Crawford University of Kentucky for the n-3 He Collaboration n-3 He Technical Review ORNL, TN 2013 -01 -08

Outline § Experiment design • • • Physics reaction and observable Experimental setup Installation in the Fn. PB 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 n + 20. 578 p n n pp p + PV observables: n n p 19. 815 Tilley, Weller, Hale, Nucl. Phys. A 541, 1 (1992) § 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 10 -7 Viviani, et al. , PRC 82, 044001 (2010),

Experimental setup Fn. PB cold neutron guide supermirror bender polarizer (transverse) Beam Monitor 10 Gauss solenoid 3 He RF spin rotator FNPB 3 He target / ion chamber n-3 He § longitudinal holding field – suppressed PC nuclear asymmetry A=1. 7 x 10 -6 (Hales) sn kn x kp 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 Fn. PB cave

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

ES&H Issues § Radiation much lower than from NPDGamma • IRR will cover 3 activities: - • 3 He detector + 6 Li aperture 3 He polarizer + 3 He monitor 3 He target/detector Beam friendly materials - • Front and back beam scans Polarimetry Physics data run 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-3 He collaboration § Spokespersons D. Bowman, M. Gericke, C. Crawford § Local Project Manager S. Penttila § Project Engineer Rick Allen § Work Subpackage Leaders M. Gericke G. Greene L. Barrón C. Crawford M. Gericke J. Hamblen I. Novikov D. Bowman J. Calarco Beam monitors Polarimetry Magnetic fields Spin rotator Target chamber Preamplifiers Data acquisition Alignment Shielding

Neutron beamline § Scope: • • § Fn. PB 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 § Scope: • • § Target / Ion Chamber Vacuum chamber, HV + sense wire frames. Gas handling system Status: • • Chamber and Macor wire frames delivered Beginning to string wire frames

Preamps § Scope • • • § $15 k 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 (10 x larger signal)

Data Acquisition § Scope: • § 128 channels of 16/24 bit ADC, > 60 KS/s $25 k data acquisition software; RAID storage array $15 k Progress: • • • selected candidate system D-t. Acq CQ 196 CPCI-96 -500 Each card 96 sim. channels + antialias filters + FPGA signal proc. runs Linux on 400 MHz XScale processor with gigabit ethernet Inexpensive c. PCI 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 xy-adjustment for theodolite Alignment V-block for trimming B-field Optical system and adjustable mount for target Progress: • Conceptual design

Equipment summary § Fn. PB / NPDG hardware • • • 3 He beam monitor SM polarizer Beam position monitor Radiation shielding Pb shield walls Beam Stop § NPDG electronics • • • B-field power supply RFSF electronics Trigger electronics SNS / chopper readout Fluxgate magnetometers Computer network § 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

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 • • • 2014 -06 -30 Integration of experiment on common stand 2014 -08 -10 IRR – begin commissioning phase 2014 -09 -15 Begin physics data taking § Runtime • • • 45 days commissioning (all equipment pre-assembled) 15 days PC transverse asymmetry 1. 7 x 10 -6 ± 1 x 10 -7 208 days PV longitudinal asymmetry 1. 3 x 10 -7 ± 1 x 10 -8

Resources § All equipment funded except Preamp, DAQ, RAID ($60 k) • • • § Solenoid and support stand RF spin rotator Target chamber Minimal utilization of SNS crafts • • • § UNAM: (CONACYT $31 k) U. Kentucky: (NSF $23 k) U. Manitoba: (NSERC $111 k) Most equipment mounted on single support structure, staged in the EDM building, craned onto NPDG det. support 3 D solid model will be drafted by graduate (Mark Mc. Crea), 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 ($75 k) • • Mainly for Engineering/Radiation support, removal of NPDG See budget spreadsheet for details