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Polarizability of the Nucleon*

Polarizability of the Nucleon*. Olena Yevetska. Motivation Experimental setup Experiments and results Summary and outlook. SFB 634. *Supported by the DFG within SFB 634. E. B. Motivation. a , b - electric and magnetic polarizabilities. m = b B. d = a E.

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Polarizability of the Nucleon*

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  1. Polarizability of the Nucleon* Olena Yevetska • Motivation • Experimental setup • Experiments and results • Summary and outlook SFB 634 *Supported by the DFG within SFB 634 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 1

  2. E B Motivation a, b- electric and magnetic polarizabilities m = bB d = aE describe the response of the nucleon internal structure to applied electric and magnetic fields V. Olmos de Leon et al., Eur. Phys. J. A10 (2001) 207 Goal: better accuracy of these constants 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 2

  3. Point t ~ Motivation Low energy Compton scattering ( E < 140 MeV) Low Energy Theorem: Powell cross section for the point like proton with anomalous magnetic moment a+b a-b Structure term Terms of higher order structure constants V. Petrun‘kin et al., Sov. J. Part. Nucl. 12 (1981) 278 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 3

  4. Experiment with Compton Scattering Eg´ Eg´ previous now Detector Detector Eg, qg qg qg´ qg´ Target Ep,d qp,d Liquid H/D-target Active high pressure H/D-target Ep = 0.4 – 8 MeV • high luminosity: • 106g/MeV/s 109g/MeV/s • background suppression: • redundancy of kinematic values • Bremsstrahlung spectrum has to be known 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 4

  5. S-DALINAC Accelerator Hall Experimental Hall 5 m Design Parameters Maximum energy: 130 MeV Energy spread : 10-4 Maximum current: 20 mA Material: Niobium Temperature: 2K g,g g, n) - Experiments ( ´) & ( Compton Scattering on Nucleon g,g ´x)- Experiments at NEPTUN Tagger ( (e,e´x) & 180°- Experiments at QCLAM Spectrometer (e,e´) - Experiments at Lintott Spectrometer 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 5

  6. Experimental Setup 6 7 7 2 5 1 8 1m 9 3 4 6 4 5 – High pressure ionisation cahmber 6 – NaI(Tl) spectrometer (10“x14“) 7 – Collimator system 8 – BPM, Quantameter 9 – NaI(Tl) spectrometer (10“x10“) 1 – Bremsstrahlung facility 2 – Collimator system 3 – Faraday cup 4 – Concrete shield 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 6

  7. Experimental Setup 6 7 7 2 5 1 8 1m 9 3 4 6 4 6 – NaI spectrometer (10“x14“) 7 – Collimator system 8 – BPM, Quantameter 9 – NaI spectrometer (10“x10“) 1 – Bremsstrahlung facility 2 – Collimator system 3 – Faraday cup 4 – Concrete shield 5 – High pressure ionisation chamber 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 7

  8. High Pressure Ionisation Chamber Determination of the energy and the position of the recoiled protons Strips in the direction of the recoiled protons p e 20 MeV ≤ Eg≤ 90 MeV 0.4 MeV ≤ Ep≤ 8 MeV 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 8

  9. High Pressure Ionisation Chamber 1 cm 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 9

  10. Proton Signals FADC IC Flash ADC (FADC) Sampling: 100 MHz, 10 ns Time window: 4.5 ms NaI(Tl) Trigger 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 10

  11. Experiments 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 11

  12. Signal Selection 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 12

  13. Correlation 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 13

  14. Correlation • Noise up to 20 MeV 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 14

  15. High Pressure Ionisation Chamber Determination of the energy and the position of the recoiled protons Strips in the direction of the recoiled protons p e 20 MeV ≤ Eg≤ 90 MeV 0.4 MeV ≤ Ep≤ 8 MeV 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 15

  16. Correlation • Noise up to 20 MeV • Edge-strips • Responce function 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 16

  17. Correlation 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 17

  18. First Results 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 18

  19. Problem with Electrons • Be-window e- (e,p)-scattering • sep≈100sgp,the same kinematics } signal in NaI(Tl) Anticounter plastic scintillator 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 19

  20. Cross Section 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 20

  21. Summary • Experiments were performed • Preliminary results were shown • Lead shield • Electronics for chamber • Anticounters: scintillators, electronics, software 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 21

  22. Outlook • Analysis is running • Simulations with GEANT4 • Better statistics • Experiment with deuteron 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 22

  23. Institut für Kernphysik, TU Darmstadt, Darmstadt, Germany: O. Yevetska A. Richter G. Schrieder S. Watzlawik • Petersburg Nuclear Physics Institute, Petersburg, Russia: V. Chizhov V. Iatsioura E. Maev E. Orishchin G. Petrov V. Sarantsev L. Sergeev Y. Smirenin • Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz, Germany: J. Ahrens SFB 634 23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 23

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