מכשור אלקטרוני – פרק 7: מכשור מבוסס על הולכה בגז

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7: . , 31-41. . http://www-spof.gsfc.nasa.gov/Education/wgeiger.html. . . . #. Description. Name. 1. Gas + h n Gas + + e -. Photo-Ionization. 2a. Gas + + V - Gas +**. - PowerPoint PPT Presentation

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  • 7: , 31-41

    7.1 7.2FIB7.3MEMS7.4 7.5

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  • http://www-spof.gsfc.nasa.gov/Education/wgeiger.html

    7.1

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  • : Ballast?

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  • -FIB-

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  • : 1 5 6 - 2 4 3 7 - 7.1.1 8

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  • 1 ( )

    Vi

    Vs

    7.1.2

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  • : Vi = 500 mlP = 0.23 atmt = 20 0C T = t +273 = 293.15 0K ni = (0.23)(0.5)/(0.08205)(293.15) = 4.8 x 10-3 mole Vi = 500 ml ; Vs = 25 ml

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  • ' 21

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  • :

    Ar e- Ar+

    Ar e- Ar+ Ar Ar+ e- Ar+ Ar e- Ar+

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  • 3

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  • 4 -

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  • 7.1.5

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  • eE = evv Bv vv : -

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  • 5

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  • 5 Bs -Bs RM

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  • 5 Ar+, O+, H+ , N+

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  • 6 - , .

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  • 1 - Fe+1Fe+2 Fe+32 - ( ...) H+ NH3+ NH2+3 -

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  • Ge+ ? , http://genesismission.jpl.nasa.gov/science/mod3_SunlightSolarHeat/MassSpectrometry/MathMassSpec/index.htmlF.W. Seares, Aguilar, Spain,1961. p.23225.12

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  • Focused Ion Beam FIB: "Mass-spectrometer vpxl ~ 106 pxl/sApxl= l x l = 60x60 nm2 7.3

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  • 7.3 -FIB

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  • FIBGe+ 500 eV 20KeV1 -Surface Modification()2 Etching ( )3 -Ion Implantation He+ 20 100 eVH+ 50 500 eV4 - Ge Cutting

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  • :FIB , http://www.fibics.com/FIBBasics.html

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  • FIB

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  • http://www.webelements.com/webelements/elements/text/Fe/isot.htmlhttp://www.sisweb.com/referenc/source/exactmaa.htmIsotopes

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  • www.astronomy.ohio-state.edu////atoms.htmlIsotopes Hydrogen, HDeuterium, DTritium, T

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  • Carbon-14 is produced by cosmic ray bombardmentof nitrogen. It is radioactive with a half-life of 5,760 years http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/T050525A.gif -

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  • Listing of known isotopes http://en.wikipedia.org/wiki/Isotope

    p12nHHe3401H2HeLiBe5612D3He4Li5BeBC723T4He5Li6Be7B8CN834H5He6Li7Be8B9C10NO91045H6He7Li8Be9B10C11N12OFNe56H7He8Li9Be10B11C12N13O14F15Ne1167H8He9Li10Be11B12C13N14O15F16NeNa121314

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  • Half LifeIsotope http://en.wikipedia.org/wiki/Isotope64 Gd 157.25(3)n/p > 1

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  • () abg

    a+2e4 amub-1emegE = mc2 m= hn/c2

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  • Pa, Protactinium Willard F. LibbyThe Nobel Prize in Chemistry 1960

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  • A= 3.8394 10-12 s-1 t1/2 = 5730 y1 y = ? s

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  • , , 1g. b b/min 11.9 1 - dN/dt dN/dt = 11.9/60 = 0.1983 b/s2 - dN/dt = AN (dN/dt)/A = Nt = 0.1983/(3.839410-12 s-1) Nt = 5.165x1010

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  • 3 - 4 - , , , 14 N0 = 14C = (0.5 x 1023)(1.3x10-12) = 0.65x1011 atoms N0/Nt = 6.5x1010/5.165x1010 = 1.26t = [ln (1.26)]/A = 0.23/(3.839410-12) = 6.02 x 1010 s t = 191 y5

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  • Mahan, College Chemistry, 1966f

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  • Br2http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/MassSpec/masspec1.htm2 - ( ...) H+ NH3+ NH2+ -ClTandem mass-spectroscopy

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