positron annihilation spectroscopy in material studies

Positron annihilation spectroscopy in materialstudies

Supervisors: Paweł Horodek, Ph.D.Krzysztof Siemek, Ph.D.

Dzelepov Laboratory of Nuclear Problems

22.07.2016, JINR Dubna

K. Biłko, M. Jurczyk, M. Kamiński, S. Nekvinda, K. Skowron Positron annihilation spectroscopy in material studies 1 / 22

Authors

Kacper Biłko - AGH University of Science and Technology inKrakow

Marta Jurczyk - AGH University of Science and Technologyin Krakow

Michał Kamiński - University of Silesia in Katowice

Stepan Nekvinda - Charles University in Prague

Konrad Skowron - AGH University of Science andTechnology in Krakow


Outline

1 Introduction

2 Theoretical background

3 Sample preparation

4 Apparatus and measurements

5 Results

6 Conclusions

7 References


Introduction

Aim of the project:

Determination of size ofdefected zones in coppersamples using positronannihilation spectroscopy(PAS).

All measurements were performed at LEPTA facility


β+ decay

Fig. 1: Schema of β+ decay [1]

p → n + e+ + νe

Fig. 2: Energy spectrum of positrons from 22Na


Interaction with matter and annihilation

Fig. 3: Path of implanted positron [2]Fig. 4: Process of annihilation described

in CM and LAB systems [3]

Eγ = mec2 ±

√12mec2E , E − energy of electron


Doppler spectroscopy

Fig. 5: Visualization of S and W parameters

S =AS

Atotal

W =AW 1 + AW 2

Atotal


Sample preparation

Fig. 6: Polishing Fig. 7: Annealing Fig. 8: Surface treatmentprocess (e.g. sandblasting)

Fig. 9: A sample before and after polishingK. Biłko, M. Jurczyk, M. Kamiński, S. Nekvinda, K. Skowron Positron annihilation spectroscopy in material studies 8 / 22

Sandblasting

Fig. 10: Sample before and aftersandblasting

Diameter of glass balls: 125µm

Fig. 11: Beforesandblasting

Fig. 12: Aftersandblasting

No. Pressure [bar] Time [min]I 1 1II 5 1III 5 3

Tab. 1: Parameters of sandblasting


Pressing

Fig. 13: Change of diameter and thickness

Pressure: 15 MPa

Fig. 14: Change of diameter and thickness

Strain of samples

ε =∆l

l= 0, 32


Milling

Fig. 15: Milling schema [4]

Fig. 16: Sample in milling machine

Fig. 17: Milling machine

Fig. 18: Sample after milling


Measuring system

Fig. 19: Schema of measuring system

Energy resolution of the detector:

1,2 keV for 511 keV Fig. 20: Measuring system


22Na source

Fig. 21: Schema of the sodium source


Apparatus

Fig. 22: Schema of measuring system

Fig. 23: Detector and positron source


Measurements

Fig. 24: Etching in HNO3 acid

Mean implantation depth in Cu

l ' 23, 1 µm

Fig. 25: Measuring the size of the sample


Results


Comparison of results - pressing

Fig. 26: Our resultsFig. 27: Comparable resultsobtained by Dryzek et al. [5]


Comparison of results - milling

Fig. 28: Our resultsFig. 29: Comparable results obtained by

Dryzek et al. [6]


Comparison of results - sandblasting

Fig. 30: Our results Fig. 31: Results obtained by Horodeket al. [7]


Conclusions

1 The Doppler broadening of the positron annihilation linemethod was successfully used to determine the size ofdefected zone in examined copper samples.

2 It has been found that all the examined samples possess somestructural defects.

3 The results obtained for pressed sample showed that thedefects are probably present in the whole sample’s volume.

4 For the milled sample it was observed that the defected zoneis relatively big and reaches up to 0,3 mm.

5 Samples exposed to sandblasting for 1 min and differentpressure did not show big differences in the level of defects.The sample sandblasted for 3 min possesses more structuraldefects.


References

[1] https://commons.wikimedia.org/wiki/File:Beta-minus Decay.svg

[2] M. Butterling, Helmholtz Zentrum Dresden Rossendorf

[3] J. Dryzek, Wstęp do spektroskopii anihilacji pozytonów wciele stałym, Krakow 1997

[4] http://web.mit.edu/2.670/www/Tutorials/Machining/mill/Description.html

[5] J. Dryzek, E. Dryzek, T. Stegemann, B. Cleff, TribologyLetters 3 (1997) 269-275, 1997

[6] J. Dryzek, S. Nojiri, M. Fujinami, E. Dryzek, K. Siemek,W. Pachla, Tribol Lett (2015) 60:16, 2015

[7] P. Horodek, J. Dryzek, Acta Physica Polonica B Vol. 9 (2016)No 2


Acknowledgements

We would like to thank:

I. N. Meshkov

A. G. Kobets

S. Z. Pakuliak

K. I. Kriukowa

I. Stekl

R. Zawodny

K. Horodek

Thank you for your attention


positron annihilation spectroscopy in material studies

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