Atomic collimated

Hagley E W, Deng L, Kozuma M, Wen J, Helmerson K, Rolston S L and Phillips W D 1999 A well-collimated quasi-continuous atom laser Sc/ence 283 1706... 

An effusive beam of atoms or molecules (see Ramsey, 1956 in fhe bibliography) is produced by pumping fhem fhrough a narrow slif, fypically 20 pm wide and 1 cm long, wifh a pressure of a few forr on fhe source side of fhe slif. The beam may be further collimated by suifable apertures along if. 

In x-ray sedimentation, a collimated beam of x-rays permits particle concentration detection as a function of mass. The relationship between the fraction of x-rays transmitted and the mass concentration of particles of atomic weight >12 is expressed as in equation 13 ... 

Detection limits for various elements by TXRF on Si wafers are shown in Fig. 4.13. Synchrotron radiation (SR) enables bright and horizontally polarized X-ray excitation of narrow collimation that reduces the Compton scatter of silicon. Recent developments in the field of SR-TXRF and extreme ultra violet (EUV) lithography nurture our hope for improved sensitivity down to the range of less than 10 atoms cm ... 

Figure 5b. Variation in the magnetic properties of metal clusters are investigated by measuring the depletion of a highly collimated cluster beam by an inhomogeneous magnetic field. Fe clusters and their oxides (FexO and Fex02) at several applied fields. The uniform depletion of Fe clusters indicates that their magnetic moments increase approximately linearly with number of atoms, as would be anticipated for incipient ferromagnetic iron. Unexpected, however, is the much larger depletion of iron oxide clusters.

Fig. 3.8. Experimental set-up to examine interaction of atom particles with the surface of a solid body by means of atom beam reflection. I - Chamber with atom particles source installed II, III - Intermediate and main chambers / -Pyrolysis filament 2 - Collimation channel 3 - Beam chopper 4 - Titanium atomizer 5 - Collimation slot 6 - Target 7 - Deflector 8 - To vacuum pump pipe 9 - Filament 10 - ZnO semiconductor sensor...

Fig. 3.10. Reaction cell. 1 - Atom gun 2 - Thermostate 3 - Metal evaporator 4 - Pt/Pt-Rh thermocouple 5/7 - Collimation holes (diameter 3 mm) 8 -Shutter 9 - ZnO semiconductor sensor 10 - Mobile quartz weight 11 - Platinum contacts terminals 12 - Vitrificated iron bars controlled by a magnet 13 -Quartz guides...

To resolve the problem applying methods of collimated atom beams, equilibrium vapour as well as radioactive isotopes, the Hall effect and measurement of conductivity in thin layers of semiconductor-adsorbents using adsorption of atoms of silver and sodium as an example the relationship between the number of Ag-atoms adsorbed on a film of zinc oxide and the increase in concentration of current carriers in the film caused by a partial ionization of atoms in adsorbed layer were examined. 

Fig. 3.12. Reaction cell. 1 - the evaporator 2 - thermocouple 3 - beam splitter 4 - semiconductor sensor (ZnO) 5 - collimating holes 6 - atom beam shutter...

Fig. 4.22. Reaction cell 1 - ZnO sensor 2 - evaporator of silver atoms 3 shutter used to terminate the beam of Ag atoms 4 - collimating apertures 5 an aperture used for pumping the cell out 6 - magnet 7 - magnetic drive for a shutter 8 - getter 9 — vacuum-measuring tube iO, 11 - electrodes 12 - thermocouple.

Figure 32. X-ray field intensities at extended Ge (220) lattice positions (0-9) for a perfectly collimated incident X-ray beam. An atomic adlayer whose center falls on one of these positions would have its characteristic fluorescence intensity modulated in the same fashion. The dashed curve represents the Bragg reflectivity profile. (From M. J. Bedzyk, Ph. D thesis, SUNY Albany, 1982.)...

Over 97% of the ions in a beam can be channeled in a crystal. This figure can be achieved for a well-collimated beam of MeV light ions, for which dmin is of order 0.1 A, directed along a low-index direction onto a single crystal sample. Typically, the sample is mounted on a goniometer which allows different low-index directions to be brought parallel to the beam during an experiment. The 2 or 3% of nonchanneled ions are those that hit the ends of the atomic rows at the surface or are scattered from surface disorder. 

The extent to which radiation of a particular frequency is absorbed by an atomic vapour is related to the length of the path traversed and to the concentration of absorbing atoms in the vapour. This is analogous to the Beer-Lambert law relating to samples in solution (p. 357 et seq). Thus, for a collimated, monochromatic beam of radiation of incident intensity I0 passing through an atomic vapour of thickness /,... 

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