Monoenergetic beams of relativistic electrons from intense laser-plasma interactions

High-power lasers that fit into a university-scale laboratory can now reach focused intensities of more than 10(19) W cm(-2) at high repetition rates. Such lasers are capable of producing beams of energetic electrons, protons and gamma-rays. Relativistic electrons are generated through the breaking of large-amplitude relativistic plasma waves created in the wake of the laser pulse as it propagates through a plasma, or through a direct interaction between the laser field and the electrons in the plasma. However, the electron beams produced from previous laser-plasma experiments have a large energy spread, limiting their use for potential applications. Here we report high-resolution energy measurements of the electron beams produced from intense laser-plasma interactions, showing that--under particular plasma conditions--it is possible to generate beams of relativistic electrons with low divergence and a small energy spread (less than three per cent). The monoenergetic features were observed in the electron energy spectrum for plasma densities just above a threshold required for breaking of the plasma wave. These features were observed consistently in the electron spectrum, although the energy of the beam was observed to vary from shot to shot. If the issue of energy reproducibility can be addressed, it should be possible to generate ultrashort monoenergetic electron bunches of tunable energy, holding great promise for the future development of 'table-top' particle accelerators.     

Electrolytic reduction of mixed solid oxides in molten salts for energy efficient production of the TiNi alloy

Fast and energy efficient technologies for material production are essential for the sustainable develop- ment of human society. The TiNi alloy is an important intelligent material[1], having high abrasive resistance, superior elasticity and good shape me…     

Collagen proteins in rats on long-term tyrosine diet

Zusammenfassung Bei Ratten wurde nach 12monatlicher Diät mit 5% 1-Tyrosin eine Alkaptonurie hervorgerufen. Die histologische Prüfung ergab eine Übersättigung mit der Homogentisinsäure, eine verringerte Aktivität der Oxidase der Homogentisinsäure in der Leber und deren massive Ausscheidung im Harn.     

Die Konstitution des Phthalylharnstoffs

Summary On the basis of experimental evidence, it is proved that phthalyl urea has the structure II, and not structure I, proposed byPiutti and generally accepted by other investigators.     

The cloacal gland complex of the Japanese quail

Résumé Chez les cailles japonaises, le complexe glandulaire du cloaque est en fait localisé dans la lèvre dorsale du cloaque et non de l'anus. Il existe un complexe glandulaire similaire et très petit du côté ventral. La glande active se colore intensément avec le réactif périodique «acide Schiff», avec la fuchsine aldéhyde, avec le bleu d'alciane et métachromatiquement avec le bleu de toluidine. Ceci indique la présence d'une sécrétion de glycomucoprotéines. Le liquide transparent sécrété est transformé en masse blanche mousseuse au contact des bactériesE. coli etProteus mirabilis, présentes en quantités équivalentes dans le proctodeum. Les gaz émis consistent probablement en H₂ et CO₂, ce dernier peut agir comme tampon et stabiliser le pH de la sécrétion autour de la valeur 6,5.

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This work was supported by U.S.P.H.S. grant No. ES 00054, Support for Toxicology Center, and by NASA research grant No. NGR 05-004-028.     

Eine neue Methode der Einstellungsschärfe des Bildes

Summary A method is described which enables the observed picture to be focused objectively. The validity of the method was tested by focusing the picture which appears in the field of the microscope. The significance of the device consists in the possibility of using it for cytophotometric purposes. The construction allows it easily to become part of the cytophotometer set.