institut für kernphysik
DESCRIPTION
Institut für Kernphysik. Frozen Spin Target. 1.- Polarised Target Operation 2.- Short Term Plans 3.- Modifications 4.- Long term plans. 17 th Crystal Ball Meeting Mainz, February 28th, 2011 Andreas Thomas. Operation. Cryostat. Movable Crystal Ball 4 p - Photon Detector. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/1.jpg)
Institut für Kernphysik
17th Crystal Ball MeetingMainz, February 28th, 2011
Andreas Thomas
Frozen Spin Target
1.- Polarised Target Operation
2.- Short Term Plans
3.- Modifications
4.- Long term plans
![Page 2: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/2.jpg)
Operation
MovableCrystal Ball
4-Photon
Detector
Cryostat
Movable5Tesla
PolarisingMagnet
First Beam with Transverse Polarisation started 15th December 2009.In 2010 we had more than 2000 hours beam on this target.
![Page 3: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/3.jpg)
Cryostat Performance
Temperature stability: T ~ +- 0.2mKelvin (one day) (typical one week measurement period).
T=24mK
T=27mK
T=29mK
t=40h
![Page 4: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/4.jpg)
Frozen Spin Target Relaxationtime
....),,,( eTemperaturFieldBRadicalMaterial
0,2 0,3 0,4 0,5 0,6 0,7 0,8
0
200
400
600
800
1000
1200
1400
1600
rela
xatio
n tim
e [h
]
holding field [T]
Relaxation time of butanol at 60 mK depending on the applied magnetic field
t
ePP
0
26 mK, 0.44T
![Page 5: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/5.jpg)
410#
# protons
radicals
Free electrons Radicals in material by chemical or radiative doping
Saturated electrons of target material not polarized (Pauli principle)
Butanol
HHHH
HOCCCCH
HHHH
N
O
CH3
CH3CH3
CH3
Tempo
Target material
Dilution factor (fButanol=10/74)determines quality of target material.
We have 9*1022 pol. Protons per cm2 in our2cm long target cell.
2cm
![Page 6: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/6.jpg)
Filling factor ~ 60% H. Ortega Spina
Vacuum
C4H10O – 60%30mm
3He/4He – 6%
![Page 7: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/7.jpg)
X-ray picture withBeamspot andNMR coil fromlast week.
Soldering of the NMR coil (target material has to be keptunder liq. Nitrogen) and installation into the cryostat.
Degree of Polarisation
![Page 8: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/8.jpg)
B=0T B=2.5T
NMR System for Polarisation measurement
MHzp 106
![Page 9: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/9.jpg)
Typical NMR Signals
Thermal Equilibrium-Signal0.5% Polarisation2.5Tesla,1Kelvin
Enhanced Signal at 70% Polarisationafter spin rotation
TE
dynTEdyn AU
AUPP
![Page 10: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/10.jpg)
Temperature measurement
AVS Picowatt Resistance Bridge
kT
BP
tanh
! Systematic error for all asymmetries!
![Page 11: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/11.jpg)
[Gerhard Reicherz, PT Ruhr-Universität Bochum,Next talk]
D-Butanol
Target materialDensity and species of the radicals
are very important for:•maximum degree of polarization
•polarization build up times•relaxation timesTrityl-Radikal
Highest Deuteron polarisation due to new doping material with narrow ESR from Bochum.
![Page 12: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/12.jpg)
Deuteron NMR Signals
![Page 13: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/13.jpg)
Proposal:
•Beam for 3 weeks in April (proton target optimized for and )
•Beam for 2 weeks in May (deuteron target broad band at 1557MeV)
•Dismounting Cryostat after final test (TE-calibration, filling factor…)
•Mounting of EPTagger.
•Mounting of liquid hydrogen target (cell length 3cm or 5cm or 10cm?).
•Test beamtime end of summer/fall.
Short term plans
![Page 14: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/14.jpg)
Transverse (Saddle coil)
and
Longitudinal (Solenoid)
Internal
Holding Field (1.2K, 0.6T)
Modifications: Magnet TechnologyDNP at 200mK and 2.5T with 70GHz microwaves.Frozen spin target (25mKelvin, 0.6T).Secondary particles punch through holding coil.All directions of polarization.
![Page 15: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/15.jpg)
High Field 1T
Threshold Production
Transverse Field
![Page 16: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/16.jpg)
Modifications: Internal Polarising Coil
DNP at 200mK and 2.5T with 70GHz microwaves.10Layer coil at 50A.Secondary particles punch through holding coil.Higher momentum threshold.
Problem is the required field homogenietyof 10-E4. Notched solenoid.3d finite element calculation, optimisationand precise production needed.
![Page 17: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/17.jpg)
New Coil with 10 layer (2.5Tesla) inMainz mechanical workshop.
![Page 18: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/18.jpg)
Talk S.Schrauf
Vacuum 3He/4He – 6%
Modifications: Active Polarised Target
![Page 19: Institut für Kernphysik](https://reader035.vdocuments.us/reader035/viewer/2022062517/5681361d550346895d9d92be/html5/thumbnails/19.jpg)
•Change from transverse to longitudinal polarisation.
•Internal polarising coil for high luminosity and precission experiments.
•Active polarised target for treshhold experiments.
Long term plans