14th Crystal Ball MeetingEdinburgh

September 13.-15. 2009Andreas Thomas

Overview installation of Polarized Target

0.- Hydrogen Target Length

1.- Polarized target tests

2.- Rail System for ‘Frozen Spin’ mode

3.- CB Frame / Electronics

4.- Schedule

Note: Hydrogen Target Length

New Xray picture of 30mm cell at 9.9.09[R.Kondratiev, O.Kostikov, A.Thomas]

Results:

3 cm cell 30.2 +- 0.3 mm h - Bump 5 cm cell 47.2 +- 0.5 mm standard10 cm cell 100.0 +- 1.0 mm High luminosity

He3/He4 Roots4000m3/h

Vacuum system

Mikrowaves70GHz

Dynamic Nuclear

Polarization

NMR-Apparatus

106MHz

Polarisation meas.

Components of the polarized target

for the Crystal Ball detector

Horizontal He3/He4 Dilutionrefrigerator

(20mKelvin)with internalHolding coil

SuperconductingPolarization magnet

5Tesla

TargetmaterialH-ButanolD-Butanol

·  Current leads (46A): Copper T=300K 70 KHTc Supracond. T= 70K 4 K

NbTi 200mm T= 4K 1.5K

Internal

Holding coil

1.3Kelvin

??? Tesla at 46AL=136mm, d=48mm, 4 layersSupport Copper-tube d=0.3mm

Full test with new insert and butanol target in June – July 2009

Polarizingmagnet

He4(liq)

Start

Stop

Calibration of the Holding coil field

B0=2.5Tesla

F= 106MHz

Observe shift of NMR-Signal depending onholding coil current

46A ~ 0.895Tesla

B0=2.5Tesla

F= 106MHz

Internal transverse Holding coil

Coil tested at 4.2KHenry OrtegaStarted PhD in Mainz

Different layers areused tooptimize thehomogeniety.

Simulation

• “Racetrack” coil: magnetic field highly non-uniform and not appropriate for a cylinder.

• “Saddle” coil: winding must fit to the so-called overlapping ellipse or “cosine” shape of current distribution (Wilson 2002 & Ašner 1999).

Ideal case for dipole magnet:

cos)(J

150mm

4-layer dipole:

N1=N2=138

N3=N4=78

High Field Solenoid

or

Transverse Field

The degree of polarization PT of the target protons (run in May ´98) :

Measurement of the degree of proton polarizationwith online NMR during GDH data taking

New NMR [N.Frömmgen]

physET

PBP

aN

pN

aN

pN

measE

Rail system needed

Cryostat

Polarizingmagnet

Crystal Ball

Polarization method

1. External magnet 2.5 T2. Polarize with microwaves3. Internal holding coil 0.7 T4. Remove external magnet5. Move CB detector in. 6. Data taking.7. Repolarization

Polarizingmagnet

MicrowavesMicrowaves + NMR

Rail system to Move the CBall, TAPS and Magnet

ACAD railsJ.Rosche

ChassisJ.Ahrens

ElectronicsA.StarostinP.Pedroni

Move magnettransverseA.Thomas

Rails are beeing alignedand fixed:R.KondratievO.Kostikov

Heavy load cars will be mountedby J.Ahrens next week

Electronics has to be mountedpartially on CB frame:A.StarostinA.LapikM. Korolija

Schedule

1.- Polarized Target - tests in dilution mode reproduced successfully

- transverse coil tested at 4K

- DNP measured

- Colleagues from Dubna in Mainz Nov.-Dec.

2.- Rail system for CBall - Cables dismounted, Rails beeing aligned now

- First move of CB next week

- DAPHNE in storage hall, TOF detectors?

- Installation of part of electronics in CB-Frame?

3.- Installation of PT in CBall - Start in October

- Test beam in December for intensity

dependent relaxation time etc.

- Transverse or Longitudinal coil.