Polarizability of the nucleon
Download
1 / 23

Polarizability of the Nucleon* - PowerPoint PPT Presentation


  • 100 Views
  • Uploaded on

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.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Polarizability of the Nucleon*' - palma


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
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

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 1


Motivation

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


Motivation1

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


Experiment with compton scattering
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


S dalinac
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


Experimental setup
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


Experimental setup1
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


High pressure ionisation chamber
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


High pressure ionisation chamber1
High Pressure Ionisation Chamber

1 cm

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 9


Proton signals
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


Experiments
Experiments

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


Signal selection
Signal Selection

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 12


Correlation
Correlation

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


Correlation1
Correlation

  • Noise up to 20 MeV

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 14


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


Correlation2
Correlation

  • Noise up to 20 MeV

  • Edge-strips

  • Responce function

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 16


Correlation3
Correlation

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


First results
First Results

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 18


Problem with electrons
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


Cross section
Cross Section

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 20


Summary
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


Outlook
Outlook

  • Analysis is running

  • Simulations with GEANT4

  • Better statistics

  • Experiment with deuteron

23.10.2008 | Institut für Kernphysik | Project C2 | Olena Yevetska | 22


  • 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


ad