SRC Users' Meeting - Synchrotron Radiation Center - University of ...
SRC Users' Meeting - Synchrotron Radiation Center - University of ... SRC Users' Meeting - Synchrotron Radiation Center - University of ...
LINEAR POLARIZATION MEASUREMENTS OF THE SYNCHROTRON RADIATION FROM A BENDING MAGNET B. M. Dirksen 1 and K. W. McLaughlin 2 1 Dept. of Medical Physics, University of Wisconsin, Madison, WI 53713 2 Dept. of Physics and Engineering, Loras College, Dubuque, IA 52001 We have measured the linear polarization of the ionizing radiation on the Stainless Steel Seya beam line 021 at the Synchrotron Radiation Center by measuring the displacement current from a gold surface after this radiation had reflected at a 45 o incident angle from another gold surface. A characteristic cos 2 () pattern was observed upon rotating these surfaces about the ionizing radiation propagation direction. After normalizing to the displacement current for the 45 o reflection surface and accounting for the reflection coefficients of gold surfaces [1,2], we can place a minimum value for the linear polarization of 97%, independent of the ionizing photon energy from 24 eV down to zero order on the beam line monochromator grating. Propagation direction for synchrotron radiation A A We would like to thank the staff and administration of the Synchrotron Radiation Center for the opportunity and assistance in accomplishing this project. The kind assistance of Mark Bissen, Roger Hansen, Bob Julian, Chris Moore, Mary Severson and Dan Wallace is particularly noted. This work is supported by NSF Grant No. 9731869. The SRC is operated under Grant No. DMR-0084402. References: [1] J. A. R. Samson, Techniques of Vacuum Ultraviolet Spectroscopy (Wiley, 1967), pages 304- 305. [2] D. W. Lynch and W. R. Hunter, "Optical Constants of Metals" in Handbook of Optical Constants of Solids, edited by E. D. Palik (Academic Press, New York, 1985), page 286.
TEMPERATURE DEPENDENCE OF N=1 BISMUTH-BASED HTSC AS SEEN IN ARPES L. Dudy 1 , B. Müller 1 , A. Krapf 1 , H. Dwelk 1 , H. Höchst 2 and R. Manzke 1 1 Humboldt Universität zu Berlin 2 Synchrotron Radiation Center (SRC) High temperature superconductivity in the cuprates mainly results from the twodimensional electronic structure of the hole-doped CuO-planes. The maximum transition temperature of this kind of material is dependent of the number of CuO-planes per unit-cell and of the layers between the CuO-layers. These layers basically isolate the CuO-planes from each other and dope holes in them. The current status of our investigations focuses on the single-layer material Bi 2 Sr 2-x La x CuO 6+ (Bi-2201), which is available in high quality single crystals. Substituting divalent Sr by trivalent La varies the hole concentration of our samples almost continuously. Because of the low transition temperature this material provides in addition the advantage of investigating the normal state with extremely small temperature broadening. For photoemission measurements Bi-2201 also benefits of the absence of bilayer splitting. This effect occurs by the interaction of electrons between narrow CuO-planes as e.g. observed in Bi 2 Sr 2 CaCu 2 O 8+ (Bi-2212). In the past we presented high-resolution photoemission results performed at SRC which below a certain temperature show along the direction of the CuO-bonds a characteristic two-peak structure [1]. It has been shown that the low energy sharp peak is strongly dependent of the applied polarization of the incident light (Fig.1a) [2]. To going further it seems like the structure isn’t visible in each M-direction (Fig. 1b). Another remarkable observation is that this structure is not only seen in the superconducting regime but also persists above the transition temperature and vanishes at higher temperatures (Fig.1c). The comparison of temperature dependence with a pseudo-1d-system [3] points to a pseudo-1d effect. In our interpretation these features are associated with one-dimensionality of the electronic structure leading to spin-charge separation [4]. The necessary condition for this state is the formation of an asymmetric electronic density, a phenomenon called stripes [5]. The present contribution follows this interpretation but profits from the raise of data collected at the SRC in order to explain the phase diagram more precisely and identifies the vanishing of the one-dimensionality with the closing of the pseudogap [6]. Recent results [7] of the universality of the pseudogap temperature T* for every CuO-plane in every cuprate will also be tried to be discussed.
- Page 2 and 3: Welcome to the 36 th SRC Users’ M
- Page 4 and 5: 12:20 - 1:10 Lunch 1:10 -1:45 Poste
- Page 6 and 7: Administration Executive Director D
- Page 8 and 9: STATUS OF THE SRC BEAMLINES AND INS
- Page 10 and 11: ACCELERATOR DEVELOPMENTS Ken Jacobs
- Page 12 and 13: HIGH ENERGY RESEARCH POSSIBILITIES
- Page 14 and 15: ATOMICALLY UNIFORM THIN FILMS ON SI
- Page 16 and 17: calculated binding energies of the
- Page 18 and 19: MANY-ELECTRON EFFECTS ON THE XE 5S
- Page 20 and 21: PHOTOELECTRON SPECTROMETRY OF ATOMI
- Page 22 and 23: PHOTOEMISSION STUDY OF USb AND UTe
- Page 24 and 25: CANADIAN SYNCHROTRON RADIATION FACI
- Page 26 and 27: SELF-ASSEMBLY OF BLOCK COPOLYMERS O
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- Page 50 and 51: References [1] S. Cho, Y. Kim, A. D
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- Page 70 and 71: Christian Ast Max-Planck Institute
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- Page 74 and 75: Tom Miller University of Illinois a
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- Page 80: NOTES
LINEAR POLARIZATION MEASUREMENTS OF THE<br />
SYNCHROTRON RADIATION FROM A BENDING MAGNET<br />
B. M. Dirksen 1 and K. W. McLaughlin 2<br />
1 Dept. <strong>of</strong> Medical Physics, <strong>University</strong> <strong>of</strong> Wisconsin, Madison, WI 53713<br />
2 Dept. <strong>of</strong> Physics and Engineering, Loras College, Dubuque, IA 52001<br />
We have measured the linear<br />
polarization <strong>of</strong> the ionizing radiation on the<br />
Stainless Steel Seya beam line 021 at the<br />
<strong>Synchrotron</strong> <strong>Radiation</strong> <strong>Center</strong> by measuring<br />
the displacement current from a gold surface<br />
after this radiation had reflected at a 45 o<br />
incident angle from another gold surface. A<br />
characteristic cos 2 () pattern was observed<br />
upon rotating these surfaces about the<br />
ionizing radiation propagation direction.<br />
After normalizing to the displacement<br />
current for the 45 o reflection surface and<br />
accounting for the reflection coefficients <strong>of</strong><br />
gold surfaces [1,2], we can place a minimum<br />
value for the linear<br />
polarization <strong>of</strong> 97%,<br />
independent <strong>of</strong> the ionizing<br />
photon energy from 24 eV<br />
down to zero order on the<br />
beam line monochromator<br />
grating.<br />
Propagation<br />
direction for<br />
synchrotron<br />
radiation<br />
A<br />
A<br />
We would like to thank the staff and administration <strong>of</strong> the <strong>Synchrotron</strong> <strong>Radiation</strong> <strong>Center</strong> for<br />
the opportunity and assistance in accomplishing this project. The kind assistance <strong>of</strong> Mark<br />
Bissen, Roger Hansen, Bob Julian, Chris Moore, Mary Severson and Dan Wallace is particularly<br />
noted.<br />
This work is supported by NSF Grant No. 9731869. The <strong>SRC</strong> is operated under Grant No.<br />
DMR-0084402.<br />
References:<br />
[1] J. A. R. Samson, Techniques <strong>of</strong> Vacuum Ultraviolet Spectroscopy (Wiley, 1967), pages 304-<br />
305.<br />
[2] D. W. Lynch and W. R. Hunter, "Optical Constants <strong>of</strong> Metals" in Handbook <strong>of</strong> Optical<br />
Constants <strong>of</strong> Solids, edited by E. D. Palik (Academic Press, New York, 1985), page 286.
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