摘要:

Teijo A˚berg died on December 29, 2000 — and with his passing we have lost a gifted and important member of our community. Over the years Teijo has made many major contributions to the science of x‐ray and inner‐shell physics. Perhaps the most visionary of these was his idea of radiative and radiationless resonant Raman scattering (RRRRS) [1]. This arose as an outgrowth of his earlier thoughts on Auger [2] and x‐ray [3] processes. It is visionary in that it attempts to unify the various aspects of inner‐shell photoexcitation and decay as different aspects of the same basic process,i.e.resonant inelastic x‐ray scattering. In honor and memory of Teijo, and as a last attempt to promote his ideas, I describe here the theory and some of its consequences. First, RRRRS is outlined in a semi‐rigorous form, with emphasis placed on the physical nature of the concepts. Then, using the example of atomicK‐shell photoionization, we see how features such as fluorescence and photoelectron lines arise in a natural way as manifestations of resonance scattering. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536356

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Ugo Fano has been a leader in theoretical Physics in the XX century giving key contributions to our understanding of quantum phenomena. He passed away on 13 February 2001 after 67 years of research activity. I will focus on his prediction of the quantum interference effects to understand the high‐energy photoabsorption cross section giving the “Fano lineshapes”. The Fano results led to the theoretical understanding of “shape resonances” (called also “Feshbach resonances”) that should be better called “Fano resonances”. Finally I will show that today this Fano quantum interference effect is behind several new physical phenomena in different fields. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536357

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

Richard Deslattes passed away on 16 May 2001 after a life dedicated to fundamental metrology. Although the themes of calibrating light, matter and fundamental constants can give three guiding principles through his career, the wide‐ranging nature of his areas of interest are encompassed by over 165 refereed publications with several cited over 100 times. He has left an enduring legacy to science. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536358

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

At the end of 1999, Mademoiselle Yvette Cauchois passed away. For over 50 years, she has contributed in a profound way to our understanding of x‐ray physics and chemistry. The main aspects of her accomplishments will be briefly outlined. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536359

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

FELs based on SASE are believed to be powerful tools to explore the frontiers of basic sciences, from physics to chemistry to biology. Intense R&D programs have started in the USA and Europe in order to understand the SASE physics and to prove the feasibility of these sources. The allocation of considerable resources in the Italian National Research Plan (PNR) brought about the formation of a CNR‐ENEA‐INFN‐University of Roma “Tor Vergata” study group. A conceptual design study has been developed and possible schemes for linac sources have been investigated, bringing to the SPARX proposal. We report in this paper the results of a preliminary start to end simulation concerning one option we are considering based on an S‐band normal conducting linac with high brightness photoinjector integrated in a RF compressor. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536360

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We review the state of the art of the VUV‐X ray FEL sources and analyze the limit of the relevant technologies and the future perspectives. Possible strategies aimed at developing the design of a road map toward very short wavelengths, very high brilliance and very short pulses are discussed. Within such a framework we report and comment on the proposed devices. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536361

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

A Doppler‐free electron spectroscopy apparatus that consists of a high‐resolution electron spectrometer and a molecular beam source has been installed on beamline 27SU at SPring‐8 in Japan. The apparatus is described and the Auger resonant Raman spectra of neon atoms recorded at the 1s ‐> 3p excitation and those of water molecules recorded at the O 1s ‐> 2b2excitation are presented to demonstrate the performance. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536362

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The LNLS (Laborato´rio Nacional de Luz Si´ncrotron) is a national laboratory in Brazil that operates a 1.37 GeV storage ring for synchrotron light users since July 1997. Eleven bending magnet beamlines are open to a wide range of possibilities for research in ultra‐violet and X‐ray spectroscopy, single crystal and powder diffraction, magnetic and anomalous scattering, protein crystallography, X‐ray fluorescence, X‐ray lithography and small angle X‐ray scattering. The recent conclusion of the booster injector opened the way for insertion devices to be accommodated in the four straight sections available. A multipolar wiggler, for protein crystallography using the MAD technique, is the first planned to be installed during 2003. The construction of the first LNLS undulator, for the vaccum ultra‐violet and soft X‐ray domain, has already started and will expand the possibilities in atomic, molecular and surface physics, as well as in catalysis and magnetism. LNLS has expanded its infra‐structure as an open multidisciplinary research laboratory into complementary areas, such as electron and scanning probe microscopy, nanostructure synthesis and molecular biology. Many technological and scientific achievements have been attained in these last five years. Some of them will be highlighted here, with emphasis in the area of nanostructured and magnetic materials. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536363

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

The basic point to be considered in this report is that X‐ray capillary optics relies on the ability of a tapered and/or bent capillary channel to act as an X‐ray waveguide. Recently several coherent phenomena associated with propagation of X‐rays in capillary optical elements have been observed. In order to describe coherent phenomena of radiation propagation a quantum‐wave theory of X‐ray channeling was developed. Simple estimations speak on possibility of X‐ray channeling in nano‐scale capillaries, but with a significant change in character of channeling. In this connection, discovery of carbon nanotubes opens new opportunities to apply capillary waveguide optics. X‐ray propagation in capillary micro‐ and nanostructures within the frame of wave approach will be discussed. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536364

出版商:AIP    

年代:1903

数据来源: AIP

摘要:

We report on the intensity modulation of the Si &Kgr;&agr; line emitted from a Mo/Si multilayer as a function of the exit angle of the photons. The observation takes place around the direction corresponding to the Bragg diffraction of Si &Kgr;&agr; by the multilayer. The sample is irradiated by an electron beam whose the energy is varied between 2 and 6 keV. An important intensity variation is observed within the angular range corresponding to the diffraction pattern of the emitting structure. A 15 &percent; enhancement of the emitted radiation is measured in the Bragg direction of the multilayer, whatever the incident electron energy. This amplification is interpreted on the basis of the reciprocity theorem. A possible application as x‐ray resonator is suggested. © 2003 American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.1536365

出版商:AIP    

年代:1903

数据来源: AIP