Light propagation and fluorescence quantum yields in liquid scintillators

For the simulation of the scintillation and Cherenkov light propagation in large liquid scintillator detectors a detailed knowledge about the absorption and emission spectra of the scintillator molecules is mandatory. Furthermore reemission probabilities and quantum yields of the scintillator components influence the light propagation inside the liquid. Absorption and emission properties are presented for liquid scintillators using 2,5-Diphenyloxazole (PPO) and 4-bis-(2-Methylstyryl)benzene (bis-MSB) as primary and secondary wavelength shifter. New measurements of the quantum yields for various aromatic molecules are shown.Comment: 11 pages, 3 figures, 1 tabl

Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

Large scale Gd-beta-diketonate based organic liquid scintillator production for antineutrino detection

Over the course of several decades, organic liquid scintillators have formed the basis for successful neutrino detectors. Gadolinium-loaded liquid scintillators provide efficient background suppression for electron antineutrino detection at nuclear reactor plants. In the Double Chooz reactor antineutrino experiment, a newly developed beta-diketonate gadolinium-loaded scintillator is utilized for the first time. Its large scale production and characterization are described. A new, light yield matched metal-free companion scintillator is presented. Both organic liquids comprise the target and "Gamma Catcher" of the Double Chooz detectors.Comment: 16 pages, 4 figures, 5 table

Scholars Forum: A New Model For Scholarly Communication

Scholarly journals have flourished for over 300 years because they successfully address a broad range of authors' needs: to communicate findings to colleagues, to establish precedence of their work, to gain validation through peer review, to establish their reputation, to know the final version of their work is secure, and to know their work will be accessible by future scholars. Eventually, the development of comprehensive paper and then electronic indexes allowed past work to be readily identified and cited. Just as postal service made it possible to share scholarly work regularly and among a broad readership, the Internet now provides a distribution channel with the power to reduce publication time and to expand traditional print formats by supporting multi-media options and threaded discourse. Despite widespread acceptance of the web by the academic and research community, the incorporation of advanced network technology into a new paradigm for scholarly communication by the publishers of print journals has not materialized. Nor have journal publishers used the lower cost of distribution on the web to make online versions of journals available at lower prices than print versions. It is becoming increasingly clear to the scholarly community that we must envision and develop for ourselves a new, affordable model for disseminating and preserving results, that synthesizes digital technology and the ongoing needs of scholars. In March 1997, with support from the Engineering Information Foundation, Caltech sponsored a Conference on Scholarly Communication to open a dialogue around key issues and to consider the feasibility of alternative undertakings. A general consensus emerged recognizing that the certification of scholarly articles through peer review could be "decoupled" from the rest of the publishing process, and that the peer review process is already supported by the universities whose faculty serve as editors, members of editorial boards, and referees. In the meantime, pressure to enact regressive copyright legislation has added another important element. The ease with which electronic files may be copied and forwarded has encouraged publishers and other owners of copyrighted material to seek means for denying access to anything they own in digital form to all but active subscribers or licensees. Furthermore, should publishers retain the only version of a publication in a digital form, there is a significant risk that this material may eventually be lost through culling little-used or unprofitable back-files, through not investing in conversion expense as technology evolves, through changes in ownership, or through catastrophic physical events. Such a scenario presents an intolerable threat to the future of scholarship

Correlations in nuclear energy recurrence relations

The excitation energies of states belonging to the ground state bands of heavy even-even nuclei are analysed using recurrence relations. Excellent agreement with experimental data at the 10 keV level is obtained by taking into account strong correlations which emerge in the analysis. This implies that the excitation energies can be written as a polynomial of maximum degree four in the angular momentum.Comment: 4 pages, 1 figure, 1 table, 9 reference

Microwave diode amplifiers with low intermodulation distortion

Distortions can be greatly reduced in narrow-band applications by using the second harmonic. The ac behavior of simplified diode amplifier has negative resistance depending on slope of equivalent I-V curve