Status update of n- 3 He experiment DOE FnPB Review, ORNL 2009-04-23 D. Bowman, S. Penttila Oak...
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Transcript of Status update of n- 3 He experiment DOE FnPB Review, ORNL 2009-04-23 D. Bowman, S. Penttila Oak...
Status update of n-3He experiment
DOE FnPB Review, ORNL 2009-04-23
D. Bowman, S. Penttila
Oak Ridge National Laboratory
M. Gericke
University of Manitoba
C. Crawford, Y. Shin
University of Kentucky
DOE FnPB Review, ORNL, 2009-04-23 #2
Outline
Executive summary
Scientific motivation• theory calculations • statistical sensitivity• systematics negligible
Experimental design• experimental layout• solenoid design• spin flipper design• 3He target / drift chamber
R&D at LANL
Experimental team
Projected schedule
Funding profile
FnPB infrastructure needed
Summary
DOE FnPB Review, ORNL, 2009-04-23 #3
Executive summary
n-3He experiment approved by the FnPB PRAC, 2008-01-07• first measurement of PV in the n-3He reaction
recent progress in experimental design• full 4-body calculation of PV observable• R&D projects on target/detector design at LANL• new spin flipper design permitting compact / less expensive layout• preliminary holding field design
leverage existing hardware / technology• major components based on similar NPDGamma instrumentation• can reuse NPDGamma electronics / power supplies
capable experimental team• experience on hadronic PV experiments at LANL
funding profile• University of Manitoba $100k target / drift chamber NSERC funded• University of Kentucky $ 57k DAQ / electronics DOE-OJI proposal• ORNL operation $120k solenoid, spin flipper, shielding, alignment, design
FnPB infrastructure• no safety hazards, no LH2 target, new power or cooling requirements
• minimal modification of FnPB cave – stand for n-3He solenoid• technician support for readiness review preparation, setup of experiment
DOE FnPB Review, ORNL, 2009-04-23 #4
Hadronic Weak Interaction (HWI)
N N
N N
Meson exchang
e
STRONG(PC)
WEAK(PV)
p-p and nuclei
Meson Exchange model (DDH)
Effective Field Theory (EFT)
DOE FnPB Review, ORNL, 2009-04-23 #5
n-3He PV Asymmetry
~ kn very small for low-energy neutrons
- essentially the same asym.- must discriminate between back-to-back proton-triton
S(I):
4He J =0+ resonance
sensitive to EFT couplingor DDH couplings
~10% I=1 contribution(Gerry Hale, qualitative)
PV observables:
19.81520.578
Tilley, Weller, Hale, Nucl. Phys. A541, 1 (1992)
DOE FnPB Review, ORNL, 2009-04-23 #6
Theoretical calculations – progress
Vladimir Gudkov (USC) PV A = 3£10-7
• PV reaction theory
Gerry Hale (LANL) PC Ay(90±) = -1.7±0.3£10-6
• R matrix calculation of PC asymmetry,nuclear structure , and resonance properties
Anna Hayes (LANL)• No-core shell model calculation with AV18 potential, etc.
Michele Viviani et al. (INFN Pisa) PV A = 3£10-7
• full 4-body calculation of scattering wave function• calculation of asymmetry within DDH framework• progress on calculation of EFT low energy coefficients• preliminary – still improving convergence of 0+ wave functions
DOE FnPB Review, ORNL, 2009-04-23 #7
Experimental sensitivity to DDH couplings
n+3Het+p (ppm)
Viviani et al.preliminary
-0.1821 -0.830-0.1447 2.373 0.0267 -0.074 0.0012 -0.016-0.1269 -0.410 0.0495 0.096
Az cont.
DOE FnPB Review, ORNL, 2009-04-23 #8
-metal shield
1010 steelflux return
10 Gausssolenoid
RF spinrotator
3He target /ion chamber
supermirrorbender polarizer
(transverse)
FnPB coldneutron guide
3He BeamMonitor transition field
(not shown)
FNPB n-3He
Experimental setup
longitudinal holding field – suppressed PC asymmetry
RF spin flipper – negligible spin-dependent neutron velocity
3He ion chamber – both target and detector
DOE FnPB Review, ORNL, 2009-04-23 #9
Solenoid holding field
uniformity requirements• B~ 0.3 G ¢B/2En=10-10 < Az
• z ~ 0.1± + alignment of wires
preliminary design• solenoid with compensation coils
at end for uniformity• -metal shield for residual earth’s field• 1010 steel flux return to prevent
saturation of -metal
design parameters• 3 m length x 50 cm diameter• B =10 G for spin flipper• j = 9 A/cm winding density• I0 = 1560 A (or end-cap windings)
simulation using COMSOL
1010 steelflux return
10 Gausssolenoid
4 m £ 55 cm diam.3 m £ 50 cm diam.
I0=1500+60 A turns I0
j = 8+1 A/cm
DOE FnPB Review, ORNL, 2009-04-23 #10
red - transverse field linesblue - end-cap windings
Radio frequency spin rotator
extension of design for NPDGamma• P-N Seo et al., Phys. Rev. ST Accel.
Beam, vol 11, 084701 (2008)
new resonator for n-3He experiment• transverse horizontal RF B-field• longitudinal / transverse flipping• no fringe field - 100% efficiency• compact geometry - efficient
- small diameter solenoid• matched to driver electronics
for NPDGamma spin flipper
prototype design• parasitic with similar design for
nEDM guide field near cryostat• fabrication and testing at UKy – 2009
NPDGammawindings
n-3Hewindings
Magnetostatic calculation with COMSOL
DOE FnPB Review, ORNL, 2009-04-23 #11
3He target / ion chamber
MC simulations of sensitivity to proton asymmetry• including wire correlations• A ~ 6 /pN
tests at LANSCE FP12• fission chamber flux calibration• prototype drift chamber R&D• new beam monitors for SNS
design of new ion chamber for NPDGamma, test at LANL
DOE FnPB Review, ORNL, 2009-04-23 #14
Left: LANL FP12 beam line with new beam monitor
Below: new beam monitor signal at 100 mA proton beam currentand neutron beam cross-section.
Inverted Signal
LANSCE FP12: test of NPDGamma monitors
DOE FnPB Review, ORNL, 2009-04-23 #15
Comparison of beam monitors
New monitors for SNS
Old monitors usedfor NPDGamma at FP12
(same gain)
RMS
RMS
DOE FnPB Review, ORNL, 2009-04-23 #16
n-3He collaboration
J.D. Bowman (PI), S.I. Penttilä Oak Ridge National Laboratory
M.T. Gericke (PI), S.A. Page, Mark McCrea University of Manitoba
C.B. Crawford (PI), Y. Shin, E. Martin University of Kentucky
C. Gillis, J. Mei Indiana University
J. Martin University of Winnipeg
V. Gudkov University of South Carolina
M. Viviani INFN, Sezione di Pisa
A. Klein, A. Salas-Bacci, A. Hayes, G. Hale Los Alamos National Lab
R. Mahurin University of Tennessee
P.-N. Seo Triangle Universities Nuclear Lab
L. Barron Universidad Nacional Autónoma de México
DOE FnPB Review, ORNL, 2009-04-23 #17
Projected schedule
Jan 2010 – Jan 2011• NPDGamma data-taking
Aug 2010 – Dec 2010• Construction of solenoid• Test of field uniformity,
alignment procedures
Feb 2011 – Mar 2011• Installation at FnPB• Commissioning
Apr 2011 – Sept 2011• 3He data-taking
June 2009 – Aug 2010• Construction of new RFSF
resonator at ORNL• Construction of 3He ion
chamber at Univ. Manitoba• DAQ electronics and software
production at Univ. Kentucky
Sept 2010 – Nov 2010• test RFSF, 3He chamber, and
DAQ at LANL FP12
window of opportunity forthe n-3He experiment between NPDGamma and Nab (2011)
ORNL Offsite, LANL
DOE FnPB Review, ORNL, 2009-04-23 #18
Funding Profile
University of Manitoba $100k NSERC funded• target / drift chamber• $500k for FnPB-related activities in last 2 years
University of Kentucky $ 57k DOE-OJI proposal• DAQ / electronics• $40k university funding for R&D
ORNL operations $120k • solenoid, spin flipper• neutron, gamma shielding• design, stands, alignment• technician support
DOE FnPB Review, ORNL, 2009-04-23 #19
Requirement of FnPB infrastructure
modification of FnPB• retained equipment:
- polarizer, beam monitor, spin flipper electronics- computer interface to chopper and TOF from SNS- DC holding field supply- beam collimation and shielding, beam stop
• support stand for solenoid- possible reuse of NPDGamma detector motion stand
• power & cooling requirements- same as NPDGamma
manpower• shielding calculations, preparation for readiness review• 1 month technician support for setup of experiment
safety hazards – none• 3He target – 1 atm inert gas; n+3Het+p (no radiation)• radiation shielding: polarizer is still the major background
DOE FnPB Review, ORNL, 2009-04-23 #20
Conclusion
by doing NPDGamma, n-3He experiments along with existing p-p, p-, n- (few body systems) we can significantly improve statistical uncertainties in DDH couplings and eliminate nuclear structure uncertainties
EFT calculations are in progress for few-body systems
n-3He is on-track to run after NPDGamma