Rrc Kurchatov Institute, Moscow, Russia

RRC Kurchatov Institute, Moscow, Russia

The equipment for X-ray polarization analysis of pulsed plasma sources. A.M.Stepanenko, M.M.Stepanenko, E.O.Baronova

2-3 July 2009, Singapore

Plasma Properties Pulsed plasma

• Irreproducibility • Anisotropy • In laser plasma- it is direction of laser radiation • In pinches-it is direction of discharge current

• X-ray spectroscopy is now designed in the assumption of isotropic plasma! • Conventional diagnostics based on analysis of intensities of line radiation should be reconsidered!

How does the polarization of radiation born? 1s2p state

Semiclassical interpretation of polarization of X-ray lines

In case of electric field presence

The basics of X-ray polarization measurements. 1.Bragg’s law

2d*sin=k

2.Reflection coefficient from crystal 2 2     16 e d   PD      tan  B K | Fhkl | 2   3   4 0 mc   V 

3.Brewster angle K = (1+ cos2 B)/2

=45

only -component is reflected!

• Why we should give our attention to the problem? • What are possible ways to measure polarization

Spectra, taken with identical polarizes are different – X-rays are polarized? Plasma focus machine, I=500 kA, Swierk, Poland Two identical polarizers are used for polarization analysis

Spectra, taken with identical polarizes are different – X-rays are polarized? Plasma focus machine, I=500 kA, Swierk, Poland

Intensity [a.u.]

Two identical polarizers are used for polarization analysis

80 70 60 50 40 30 20

1

ArXVII- P

B 3

ArXVII- P

3,86 3,88 3,90 3,92 3,94 3,96 3,98 4,00 4,02 4,04 4,06 Intensity [a.u.]

120 100 80 60

1

ArXVII- P

A 3

ArXVII- P

40 20 0 3,86 3,88 3,90 3,92 3,94 3,96 3,98 4,00 4,02 4,04 4,06

Wavelength [A]

Spectra of ArXVII, taken by identical polarizers in single shot

Spectra, taken with identical polarizes are different – X-rays are polarized? Plasma focus machine, I=500 kA, Swierk, Poland

Intensity [a.u.] 80 70 60 50 40 30 20

1

ArXVII- P 3

B

ArXVII- P

3,86 3,88 3,90 3,92 3,94 3,96 3,98 4,00 4,02 4,04 4,06 120

Intensity [a.u.]

T e = 900 eV, ne = 4*1021 cm-3

Spectra, taken with identical polarizes are different – X-rays are polarized? Plasma focus machine, I=500 kA, Swierk, Poland

Intensity [a.u.]

Two identical polarizers are used for polarization analysis

80 70 60 50 40 30 20

1

ArXVII- P

B 3

ArXVII- P

3,86 3,88 3,90 3,92 3,94 3,96 3,98 4,00 4,02 4,04 4,06

Spectra of ArXVII, taken by identical polarizers in single shot

Intensity [a.u.]

120 100 80 60

1

ArXVII- P

A 3

ArXVII- P

40 20 0 3,86 3,88 3,90 3,92 3,94 3,96 3,98 4,00 4,02 4,04 4,06

Wavelength [A]

T e = 900 eV, ne = 4*1021 cm-3

4 channel compact convex spectrometer with flat output windows.

3 slits, 1*13mm2

+20Be

Pinhole image

Input diaphragm Diafragm

3 crystals 100 pinhole+20Be Lead, 0.5 mm

Polarization analysis on x-pinch , discharge current 80 kA, Cu wires X-pinch, source size 1mm, plasma to crystal distance is 160 mm Cu, L-shell (1s22s22p6 1S0), 1 shot, 3 mica crystals

2s22p6 1S0 –2s22p53p 1P1 2s22p6 1S0 –2s22p53p3P1

2s22p6 1S0 –2s22p53d 1P1 2s22p6 1S0 –2s22p53d 3D1

2s22p6 1S0 –2s22p53s 1P1 2s22p6 1S0 –2s22p53s 3P1

L-shell spectra of Cu are polarized!

Parameters of 4 channel spectrometer Advantages: compact sizes, wide energy range, simplicity of alignment, high resolution with point-like X-ray sources, adopted to use MCP detectors Resolution 3*10-3 Dispersion 0.08- 0.16 А/мм Energy range 0.82 keV – 10 keV

Disadvantages: reflection coefficient is not well known, field of view of crystals is different

First single crystal X-ray spectropolarimeter Quarz crystal serves as polarimeter, it contains series of planes at 120 to each other

Polarization analysis of X-ray tube radiation

Cu К-alpha radiation, reflected in fourth order of 10-10 cut.

Equal reflection coefficients in both channels

First single crystal X-ray polarimeter CHANNEL 2

CHANNEL1

Advantages: 1. identical field of view for both polarization components 2. equal reflection coefficients

Disadvantages: 1. needs careful alignment

Conclusions. Due to the presence of directed electromagnetic Fields, X-ray spectroscopy measurements should be accompanied by polarization analysis. New perspective equipment for X-ray Plasma Polarization Spectroscopy was manufactured and tested: 1. 4 channel spectrometer 2. The single crystal spectropolarimeter

Thank you for your attention