1. 実用材料における昇温脱離スペクトル 1 Thermal desorption study of selected austenitic stainless steel: Bache, J.-P., J.Vacuum Science and Technology A21, 167(2003).

2. 実用材料における昇温脱離スペクトル 2 Thermal desorption study of selected austenitic stainless steel: Bache, J.-P., J.Vacuum Science and Technology A21, 167(2003). ARC:Melted in electric arc furnace AOD:Arc-oxygen decarburation ESR:Electro slag remelting MC(N) precipitates

3. Precipitates 3 MC: TiC/TiC M(CN): Nb(CN)/Ti(CN)/AlN M 23 C 6 : Cr 16 Fe 5 Mo 2 )C 6 ;(FeCr) 23 C 6 ;(Cr 17 Fe 4-5 )C 6 M 6 C: (CrCoMoNi) 6 ;(TiNi) 6 C;(Fe 3 Mo 3 )C Austenitic Stainless Steels, Microstructure and Mechanical Properties P.Marshall (Elsevier Applied Science, 1984),pp.32.

4. 測定の課題 4 Surface desorption bulk outgassing Non-uniformity (poly crystalline, interfaces, precipitates Temperature uniformity is most important

5. TDS スペクトル 5 316 Ti ARC+AOD 316LN ESR

6. 全 H 2 放出量 6 950 ℃ × 2h heating Complete outgassing TDS after charging H 2 No vented: 480 ℃ peak Air vented: 680 and 800 ℃ peaks

7. Comments on TDS measurement 7 1.Surface composition change monitored by XPS 110 ℃ : oxide and hydroxide of Cr and Fe + H 2 O 270 ℃ : reduction of iron oxide, decrease of H 2 O and C 570 ℃ : increase of Cr hydroxide, Segregation of Mn and Si 870 ℃ : complete reduction of oxide, metallic surface 2.Origin of desorption peak 480 ℃ peak: diffusible interstitial H. E d =0.52eV 600-800 ℃ : reduction of Fe or Cr oxide Cracks in the thick oxide layer causes sharp peak above 600 ℃ in case of air bake process 500-600 ℃ peak for 316 Ti: Hydrogen trapped at precipitates Hydrogen charging without air vent

8. Electron Stimulated Desorption (ESD) Menzel, Gomer :J Chem Phys 41(1964)3311. Redhead:Can.J.Phys. 42(1964)886. FE tube Ta getter doser e-gun tip W surface filament Y.Ishikawa, Rev.Phys.Chem.Japan 16,83, 117 (1942). 1.M.L.Knotek: Rep. Prog. Phys. 47,1499(1984). 2.M.L.Knotek: Physics Today September, 24 (1984). 3.R.D.Ramsier, T.T.Yates: Surface Science Report 12, 246(1991). 4.Desorption induced by electron transition (DIET) 1:Springer series in chemical physics, 24,1(1983).

10. 電離真空計 電離真空計の感度 イオン化断面積 電子の飛距離 イオン収集効率

11. 電子励起脱離イオン Arakawa-Tuzi (C.Oshima)

12. 電子衝撃脱離 Electron stimulated desorption (ESD) Desorption induced by electronic transition(DIET)

13. M.L.Knotek:Rep.Prog.Phys. 47(1984)1499. Menzel-Gomer-Redhead model (MGR) ★ Franck-Condon excitation to antibonding state Escape probability: 全脱離断面積 ★ neutral Franck-Condon S r :slope v:velocity Quantum mechanical formulation Escape time ～ 10 -14 s Excited state life time For H/W(001), D/W(001)

14. Threshold energy N2N2 CO CO + Knotek 、 Fig.8. Thershold energy: 5eV for N 2 10eV for CO

15. O + desorption K 2 O,CaO,ScO 3,V 2 O 5 Maximal valency: Cation is ionized to electron configuration of rare gas atom Ti 4 + in TiO 2 3 electrons of O 2- released Maximal valency Sub-maximal valency Knotek-Feibelman model for ionic surfaces Maximal valency ionic compound Core-hole No O + desorption

16. Antoniewicz model for physisorbed molecules 正イオン ★ positive ion formation ⇒ attraction by image force P.R.Antoniewicz, Phys.Rev. B21, 3811(1980). Surface electron density Repulsion by Pauli principle

17. ESDIAD Electron Stimulated Desorption Angular Distribution

18. NH 3, H 2 O/ Ni(111) H + from NH 3 NH 3 O/Ni(111) H2OH2O H 2 O+ O/Ni(111) Czyzewski, Maday, Yates; Phys.Rev.Lett. 32, 777(1974).

19. 19 Photo stimulated desorption in accelerators CERN 99-05, Dynamic outgassing, O.Groebner [Test chamber for SR induced outgassing] [W] E: [GeV] I: [mA]  [m] bending radius Photon flux per circumference [m -1 ] Total radiation power: Total gas desorption Dynamic pressure rise

20. 20 [Beam cleaning] D: beam dose [mAh] a=0.6 ～ 1 Straight line: constant S Data for OFHC copper

21. 21 [Before degass process] [After degass process] ! High temperature degass is efficient For thermal outgassing. Not so efficiebt for photo induced outgassing.

22. 22 Beam induced gas desorption Particle balance p:pressure in the beam line

23. 23 Low energy photon induced desorption: PSD Ag plated D2D2 H2H2

24. 24 Electron induced desorption from cryogenic surfaces Bass, Sanche; Low Temperature Physics 29, 202 (2003). O - desorption Dissociative Electron Attachment (DEA)