Radiation Effects in Solids after High Energy Electron Irradiation

Transcription

1 KIPT Radiation Effects in Solids after High Energy Electron Irradiation Yuri Petrusenko NATIONAL SCIENCE CENTER Kharkov Institute of Physics & Technology CYCLOTON Science & Research Establishment Kharkov, Ukraine

2 KIPT National Science Center Kharkov Institute of Physics & Technology Kharkov, Ukraine 2

3 KIPT National Science Center Kharkov Institute of Physics & Technology Found in 1928 Staff: 2500 Accelerators: more then 15 Stellarators: "Uragan-3M, Uragan-2M Institutes: Institute of Solid State Physics, Materials Science & Technologies Institute of High-Energy Physics & Nuclear Physics Institute of Plasma Physics Institute of Plasma Electronics & New Methods of Accelerating Institute of Theoretical Physics 3

4 KIPT National Science Center Kharkov Institute of Physics & Technology CYCLOTON Science & Research Establishment (Center of joint use of accelerator facilities) Basic facilities: ELIAS electrostatic accelerator (High Voltage Corporation, USA) Compact Cyclotron CV-28 (The Cyclotron Corporation of Berkeley, USA) 4

5 Outline: Effect of point defects on critical current of high-t c superconductors Point defects and recovery kinetics in irradiated bulk metallic glasses Defect production and recovery process in zirconium-based alloys The role of defects in the electronic transport in thin-film silicon Compact Cyclotron CV-28: Present and future 5

6 ELIAS electrostatic accelerator of electrons as precise generator of point-like defects in solids Parameters: Energy of electron beam MeV Beam current mka 6

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8 ELIAS accelerator s output facility (cryostat for irradiation) 8

9 Effect of point defects on critical current of high-t c superconductors Question: Whether point defects are effective pinning centers in high-tc supercondutrors? STCU Projects #655, #655A Yu. Petrusenko et al., Journal of Physics: Conference Series (2010). Yu.T. Petrusenko and A. V. Bondarenko, Functional Materials, 16, No. 1 (2009), Yu.T. Petrusenko and A. V. Bondarenko, Low Temp. Physics, 35, No.2 (2009), Yu.T. Petrusenko, Low Temp. Physics, 36, No.1 (2010),

10 Experimental Samples: High-quality YBaCuO single crystals, Tc 93 K. Irradiation: 2.5 MeV electrons a liquid helium cryostat at temperatures T 10 K at doses up to 3x10 18 el/cm 2. temperature range for operation from 10 to 400 K. magnetic field up to 6T. accuracy of temperature control and regulation K. a goniometric sample holder to rotate the crystals with respect to the vector of the magnetic field. Technique: Current-voltage characteristics measured by dc-resistivity method. 10

11 YBa 2 Cu 3 O 7-X single crystal H = 1.5 T, Ft = 3.1*10 18 el/cm 2 Irradiation with 2.5 MeV electrons at 10 K Resistivity, µohm*cm before irrad. (H = 0 T) irrad. (H = 0 T) irrad. angle= 0 o irrad. angle=14 o irrad. angle=90 o Temperature, K 11

12 YBa 2 Cu 3 O 7-X single crystal T=77 K, angl H,ab =14 o, H=1.5 T Fluence x10 18 el/cm E, mv/cm Current density, ka/cm 2 12

13 YBa 2 Cu 3 O 7-x single crystal H = 1.5 T, angle H,ab = 14 o Current density, ka/cm Dose, x10 18 el/cm Temperature, K 13

14 YBa 2 Cu 3 O 7-X single crystal T = 85 K, angle H,ab = 14 o 36 Dose, x10 18 el/cm Critical current, ka/cm before irradiation H, T 14

15 YBa 2 Cu 3 O 7-x single crystal irradiated with 2.5 MeV elertrons at 10K H = 1.5 T, angle H ab = 14 o 35 J cirr / J co, arb. un K 83 K 79 K 77 K 0 0 1x x x10 18 Dose, el / cm 2 15

16 YBa 2 Cu 3 O 7-X single crystal H = 1.5 T, T = 81 K Irradiation with 2.5 MeV electrons at 10 K Current density, ka/cm before irradiation 2.3*10 18 el/cm 2 annealing at 330 K Angle, grad 16

17 Conclusions: It has been first demonstrated that point defects generated by the ~MeV electron beam are the effective pinning centers of magnetic vortices in high-t c crystals, and this determines a substantial rise in the critical current density in irradiated superconductors. 17

18 ELIAS Accelerator Point Defects and Recovery Kinetics in Irradiated Bulk Metallic Glasses Yu.Petrusenko, A. Bakai et. al., Mater. Res. Soc. Symp. Proc (2008). Yu. Petrusenko, A. Bakai et al., Intermetallics 17 (2009) 246. Yu.Petrusenko, A. Bakai et al., J. Alloys Compounds (2010), doi: /j.jallcom/ Yu. Petrusenko A. Bakai, I. Neklyudov et al., Proc. TMS 2010 Annual Meeting, Seattle, USA, Feb ,

19 The problem of structural properties and structural defects of amorphous solids is still of vital importance. To make clear whether stable point defects exist in metallic glasses (MGs), we have studied the accumulation and recovery kinetics of radiation defects in ZrTiCuNiBe and ZrTiCuNiAl bulk MGs irradiated with 2.5 MeV electrons at T ~ 80 K. 19

20 Experimental: The method: - low-temperature electron irradiation - isochronal annealing - electrical resistance measurements Samples: amorphous alloys, Zr 41 Ti 14 Cu 12,5 Ni 10 Be 22,5 Zr 52.5 Ti 5 Cu 17.9 Ni 14.6 Al 10, 0.05 mm in thickness, prepared by the spinning method Irradiation: 2.5 MeV electrons at ELIAS electrostatic accelerator Maximal exposed dose 7.5x10 19 e - /cm 2 Temperature of irradiation T irr ~80 K. Isochronal annealing: temperature range K, 10 K step Electrical resistance measurements: at T= 80.5 K by precise fore-probe method, accuracy - 5 ppm 20

21 1,0016 1,0014 1,0012 ZrTiCuNiBe R irr /R 0 1,0010 1,0008 1,0006 1,0004 1,0002 1,0000 0,9998 0,9996 ZrTiCuNiAl 0,9994 0, D, x10 18 e - /cm 2 Dose dependences of relative electrical resistance for ZrTiCuNiBe and ZrTiCuNiAl irradiated with 2.5 MeV electrons at 85 K. 21

22 (R irr -R ann )/(R irr -R o ), % T ann, K Recovery of irradiation-induced resistance of ZrTiCuNiBe irradiated with 2.5 MeV electrons at 85 K to dose 7.5x10 19 e-/cm 2. 22

23 5,0x10-6 4,0x10-6 3,0x10-6 dr / dt 2,0x10-6 1,0x10-6 0,0-1,0x T ann, K Recovery spectrum of irradiation-induced resistance for ZrTiCuNiBe irradiated with 2.5 MeV electrons at K to dose 7.5x10 19 e-/cm 2.

24 Effective activation energies of recovery stages for ZrTiCuNiAl and ZrTiCuNiBe bulk metallic glasses irradiated with 2.5 MeV electrons (Estimated data) ZrTiCuNiBe: E 150K = 0.46 ev E 225K = 0.69 ev ZrTiCuNiAl: E 135K = 0.40 ev E 225K = 0.69 ev 24

25 Polycluster amorphous structures A. S. Bakai, Polycluster amorphous solids. Moscow: Energoatomizdat (1987) A.S. Bakai, in: Topics in Appl. Phys., v. 72 (1994) A fragment of the 2-D polycluster Intercluster and inner boundaries are shown: -regular sites; circles with dot are coincident sites; semicircles with dot are noncoincident sites 25

26 Subcluster structure of the Zr Ti Cu Ni Be BMG A.S. Bakai I. M. Mikhailovskij, et al., Low. Temp. Phys., 28, 279 (2002). 10 nm 10 a b Field ion microscopic images of the V-01 BMG after pulsed field evaporation at a rate about 1 nm/s (a) and hydrogen promoted field etching (b). F f (arb. units) ,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 d (nm) 26

27 Conclusions: Point defects are stable in metallic glasses and the defect mobility is a thermally activated process. Activation energies of recovery processes in metallic glasses are lower than migration energy of vacancies in crystals. Intercluster boundaries are the most probable sinks of the point defects. Structural model of densely random-packed spheres or free volume model is irrelevant to bulk metallic glasses. The results are in accord with the polycluster structure of bulk metallic glasses. It is reasonable to predict high radiation tolerance of bulk metallic glasses. 27

28 ELIAS Accelerator The role of defects in the electronic transport in thin-film silicon STCU Projects #655A, #P332, #P429 O. Astakhov, R. Carius, Yu. Petrusenko et al., Mater. Res. Soc. Symp. Proc. 989 (2007) O. Astakhov, R. Carius, Yu. Petrusenko, et al, Physica Status Solidi-RRL 1 (2007) R77. O. Astakhov, F. Finger, R. Carius, et al., Thin Solid Films 515 (2007) p O. Astakhov, R. Carius, A. Lambertz, et al., J. Non-Cryst. Solids 354 (2008) O. Astakhov, et al. Physical Review B 79 (2009) p O. Astakhov, et al. Physica Status Solidi C 1-4 (2010). 28

29 a-si:h and µc-si:h Material for cheap production: - Large area electronics - Photovoltaics - Photosensors - Thin Film Transistors (TFT displays) Defects strongly affect the quality of devices In order to improve devices quality the nature of defects and their role is investigated Electron bombardment a tool for the defect density manipulation 29

30 µс-si:h materials for solar cell, photosensors and large scale electronic device production FZJ-IPV Sample preparation Transportation NSC-KIPT Irradiation E=2МэВе - J=5мкА*см -2 T irr ~80 K D max =10 19 е*см -2 Investigation ESR (40-300К) Dark and photoconductivity Spectral absorption, etc. Transportation at 77 K Reloading at 77К Test measurements 30

31 Electron Spin Resonance (ESR) measurements µc-si:h a-si:h Irradiated e- e- Annealed Deposited Deposited Irradiated 50 o C 80 o C 120 o C 160 o C 31 NS (cm-3 ) Deposited Irradiated 50 o C 80 o C 120 o C 160 o C ESR intensity Treatment g-value

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33 Spin density N S in as-deposited material (black circles) and N S after irradiation (black stars) as a function of silane concentration (SC=SiH 4 /SiH 4 +H 2 ). 33 The ratio N S Irr /N S Dep is shown with triangles.

34 Conclusions: Effective use of low-temperature electron irradiation as a method of increasing the defect density in thin-film silicon without changing its microstructure. Elucidation of the role of defects in electron transport in the material. The results are of importance for improving the silicon-based thin-film device production technology. 34

35 Primary defect production and recovery process in binary Zr- based alloys (Zr-Sc, Zr-Y, Zr-Gd, Zr-Dy, Zr-La) V. Borysenko, Yu. Petrusenko and D. Barankov, MRS Fall Meetings (Symposium V: Materials Research Needs to Advance Nuclear Energy), Boston, USA, November 30 December 4,

36 ρ(t)/ ρ o, % T, K Zr Zr-Sc Zr-Dy Zr-Y Zr-Gd Zr-La Recovery of irradiation-induced resistance for Zr-based alloys irradiated with 2 MeV electrons at ~80K to dose 1.4x10 19 e-/cm 2 36

37 - d[( ρ(t)/ ρ o ]/dt, % K -1 2,0 1,5 1,0 0,5 Zr Zr-Sc Zr-Dy Zr-Y Zr-Gd ZrLa 0, T, K Recovery spectrum of irradiation-induced resistance for Zr-based alloys 37 irradiated with 2 MeV electrons at ~80K to dose 1.4x10 19 e-/cm 2

38 Conclusions: Alloying atoms of rare earths have been found to interact effectively with point defects in the zirconium matrix. The observed processes effects on annihilation and redistribution of radiation defects 38

39 Compact Cyclotron CV-28: Present & Future (Putting into operation 2011) 39

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46 Compact Cyclotron CV-28 Particles H + Beam Energy Range 2 24 MeV External Current at Minimum Energy 70 мкa External Current at Maximum Energy 70 мкa Internal Current 500 мкa D MeV 100 мкa 100 мкa 500 мкa 3 He MeV 15 мкa 70 мкa 150 мкa 4 He MeV 10 мкa 50 мкa 100 мкa 46

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50 Damage parameters for Cyclotron s ions Particles H + Max Beam Energy 24 MeV Average Current 50 мкa Max Dose Rate ~5x10-6 dpa/sec Max Dose ~0.25 dpa D + 14 MeV 50мкA ~10-4 dpa/sec ~5.0 dpa 3 He MeV 50мкA ~2x10-4 dpa/sec ~10 dpa 4 He MeV 50мкA ~10-3 dpa/sec ~ 50 dpa 50

51 Neutron source based on Compact Cyclotron CV-28 (Thick target Be source) 9 Be(d,n) 10 B D + beam Be target ~MeV neutrons Max Flux Density ~10 12 n/cm 2 sec Max Neutron Dose ~ n/cm 2 (for D + Beam Energy -14 MeV, Beam Current -100 mka) 51

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53 Neutron source Development of radiation-resistant magnetic field sensors Development and testing of neutron detectors Element analysis Neutron effects on biological materials etc. 53

54 KIPT WELCOME for planning and realization of joint Projects 54