Deuteron Polarimetry at COSY September 13, 2007 D.Eversheim, PSTP 2007 1 Some Introductory Remarks...
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Transcript of Deuteron Polarimetry at COSY September 13, 2007 D.Eversheim, PSTP 2007 1 Some Introductory Remarks...
September 13, 2007 D.Eversheim, PSTP 2007 1
Deuteron Polarimetry at COSY
• Some Introductory Remarks
• Some Experimental Details Concerning EDDA
• Deuteron Polarimetry with EDDA
• Deuteron Polarimetry with ANKE
• Summary
September 13, 2007 D.Eversheim, PSTP 2007 2
Deuteron Polarimetry at COSYSpin½ + Spin½ Observables
Number of Spin½ + Spin½ Observables
- unpol.- pol.
256
128
36 25 3
Example:
i
0 i*
i= aaσ
ip j, j
ol*
i
= aaσ
Naiv + P + T Pauli
(N-N) (p-p) (e-N)
M = f(a1 a6)
M = f(a1 a5)
September 13, 2007 D.Eversheim, PSTP 2007 3
Deuteron Polarimetry at COSYSome Experimental Details
Bistricky et al, J. de Phys. 39
25 Observables for Identical Particles (Spin 1/2 + Spin 1/2 )
September 13, 2007 D.Eversheim, PSTP 2007 4
Deuteron Polarimetry at COSY
Polarized Deuterons are interesting for several reasons:
• Measure spin observables and learn more about N-N forces.But:Deuteron break-up imposes additional difficulty.
• Use polarized deuterons via quasielastic scattering to do
physics (infinitive momentum frame).
But: Results may be affected by the presence of the proton (FSI, . . . )
• Test of discrete symmetries (P, T, . . . .)
n
Reasons for Polarized Deuteron Physics
September 13, 2007 D.Eversheim, PSTP 2007 5
Deuteron Polarimetry at COSYEDDA & ANKE @ COSY
September 13, 2007 D.Eversheim, PSTP 2007 6
Deuteron Polarimetry at COSYThe EDDA Detector
Collaboration from:• University Bonn (J. Bisplinghoff)• University Hamburg (W. Scobel)• FZ-Jülich (R. Maier)
September 13, 2007 D.Eversheim, PSTP 2007 7
Deuteron Polarimetry at COSY
Fiber Target:
L ≈ 5∙1029 /(cm2s)
Tolerate up to Np = 2∙108 stored
protons (CH2, C sturdier).
ABT:
Density ρF = 2∙1011/cm2
L = ρνNp with ν = 1.5MHz
L = 3∙1027/(cm2s) for
Np = 1010 protons.
Rates and Luminosities Detectable Particles
Rates and Luminosities
Minimum energy needed to reach the EDDA ring layer:(Scaler mode)
September 13, 2007 D.Eversheim, PSTP 2007 8
Deuteron Polarimetry at COSYpd Elastic Scattering
September 13, 2007 D.Eversheim, PSTP 2007 9
Deuteron Polarimetry at COSY
Count-Rates
September 13, 2007 D.Eversheim, PSTP 2007 10
Deuteron Polarimetry at COSYAlgorithm
September 13, 2007 D.Eversheim, PSTP 2007 11
Deuteron Polarimetry at COSY
!pure states!favorable transition combination
0 1 1 1 0 0 1 0 0
1
2
3
4
56
7
eps
Deuteron Beam Polarizations
September 13, 2007 D.Eversheim, PSTP 2007 12
Deuteron Polarimetry at COSYEDDA Set-Up as an Efficient Polarimeter
Vector- and tensoranalysingpowers were calculated from the 4 quadrants (L, R, T, B) with relative specific efficiencies (eps); eps_L was set to be 1.
September 13, 2007 D.Eversheim, PSTP 2007 13
Deuteron Polarimetry at COSYQuasielastic Scattering
pp
The tensor analyzing powers are 0 within the errors – as expected.
There is a sizable vectoranalyzing power at 800 MeV.
September 13, 2007 D.Eversheim, PSTP 2007 14
Deuteron Polarimetry at COSYComparison of the PVector Measured at the LEP and EDDA
September 13, 2007 D.Eversheim, PSTP 2007 15
Deuteron Polarimetry at COSYDetermining the Analyzing Power for EDDA @ 1850MeV/c
Phys. Rev. C65 (2002) 34003Phys. Rev. C36 (1987) 2010
Remarks:
i) SPIN@COSY measures at 1850 MeV/c
ii) ANKE measures at 2400 MeV/c
September 13, 2007 D.Eversheim, PSTP 2007 16
Deuteron Polarimetry at COSYEDDA & ANKE @ COSY
September 13, 2007 D.Eversheim, PSTP 2007 17
Deuteron Polarimetry at COSYThe ANKE Detector
September 13, 2007 D.Eversheim, PSTP 2007 18
Deuteron Polarimetry at COSYCalibration of the ANKE Polarimeter
1.
2. 2.
(
(
0y
y yy
3 0yy
1. quasifree np dπ (A )
2. dp elastic (A ,A )
3. dp He π ANKE : A (0°) = 0.461± 0.03)
SATURNE : = 0.458 ± 0.014)
Results:
No losses in polarization during acceleration
Phys. Rev. ST Accel. Beams (2006) 9
September 13, 2007 D.Eversheim, PSTP 2007 19
Deuteron Polarimetry at COSYPolarimeter Comparison
Proportionality factors with respect to the maximally possible vector- (αz) and tensorpolarizations (αzz).
September 13, 2007 D.Eversheim, PSTP 2007 20
Deuteron Polarimetry at COSYPolarization Export Technique
September 13, 2007 D.Eversheim, PSTP 2007 21
Deuteron Polarimetry at COSYSummary
ANKE can identify polarized neutrons.
EDDA & ANKE could be „calibrated“ against the LEP.
EDDA & ANKE could be calibrated absolutely.
EDDA was tuned to become an efficient polarimeter.
Deuteron polarimetry works at EDDA & ANKE.
September 13, 2007 D.Eversheim, PSTP 2007 22
Deuteron Polarimetry at COSYThe Principle of an Time Reversal Invariance Test