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