RF System Upgrades to the Advanced Photon Source Linear Accelerator in Support of the Fel Operation

The S-band linear accelerator, which was built to be the source of particles and the front end of the Advanced Photon Source injector, is now also being used to support a low-energy undulator test line (LEUTL) and to drive a free-electron laser (FEL). The more severe rf stability requirements of the FEL have resulted in an effort to identify sources of phase and amplitude instability and implement corresponding upgrades to the rf generation chain and the measurement system. Test data and improvements implemented and planned are describedComment: LC 2000 (3 pages, 6 figures

Testing and Implementation Progress on the Advanced Photon Source (APS) Linear Accelerator (Linac) High-Power S-band Switching System

An S-band linear accelerator is the source of particles and the front end of the Advanced Photon Source injector. In addition, it supports a low-energy undulator test line (LEUTL) and drives a free-electron laser (FEL). A waveguide-switching and distribution system is now under construction. The system configuration was revised to be consistent with the recent change to electron-only operation. There are now six modulator-klystron subsystems, two of which are being configured to act as hot spares for two S-band transmitters each, so that no single failure will prevent injector operation. The two subsystems are also used to support additional LEUTL capabilities and off-line testing. Design considerations for the waveguide-switching subsystem, topology selection, control and protection provisions, high-power test results, and current status are describedComment: Linac 2000 paper No. THE07 3 pages with 3 figure

Multiple-scattering Modelling of Scattering by Biological Cells

Past work on scattering by biological cells has been restricted to unrealistic oversimplified models of cells, or uses slow methods unsuited for calculations involving large numbers of cells or varying illumination. We consider the systematic use of fast, accurate methods for modelling light scattering in realistic complex biological cells. This will allow, for example, the study of light scattering by realistic ensembles of cells, which is immediately applicable to optical cancer detection, and remote sensing of microorganisms. It will also be possible to study light scattering by cells under constantly varying illumination, such as encountered in applications like flow cytometry

Gamma-Ray Spectroscopy of Λ16^{16}_\LambdaO and Λ15^{15}_\LambdaN Hypernuclei via the 16^{16}O(K−,π−)(K^-, \pi^-) reaction

he bound-state level structures of the $^{16}_{\Lambda}$O and $^{15}_{\Lambda}$N hypernuclei were studied by $\gamma$-ray spectroscopy using a germanium detector array (Hyperball) via the $^{16}$O ($K^-, \pi^- \gamma$) reaction. A level scheme for $^{16}_{\Lambda}$O was determined from the observation of three $\gamma$-ray transitions from the doublet of states ($2^-$,$1^-$) at $\sim 6.7$ MeV to the ground-state doublet ($1^-$,$0^-$). The $^{15}_{\Lambda}$N hypernuclei were produced via proton emission from unbound states in $^{16}_{\Lambda}$O . Three $\gamma$ -rays were observed and the lifetime of the $1/2^+;1$ state in $^{15}_{\Lambda}$N was measured by the Doppler shift attenuation method. By comparing the experimental results with shell-model calculations, the spin-dependence of the $\Lambda N$ interaction is discussed. In particular, the measured $^{16}_{\Lambda}$O ground-state doublet spacing of 26.4 $\pm$ 1.6 $\pm$ 0.5 keV determines a small but nonzero strength of the $\Lambda N$ tensor interaction.Comment: 22 pages, 17 figure

AA--Dependence of ΛΛ\Lambda\Lambda Bond Energies in Double---Λ\Lambda Hypernuclei

The $A$-dependence of the bond energy $\Delta B_{\Lambda\Lambda}$ of the ${\Lambda\Lambda}$ hypernuclear ground states is calculated in a three-body ${\Lambda + \Lambda + {^{A}Z}}$ model and in the Skyrme-Hartree-Fock approach. Various ${\Lambda\Lambda}$ and $\Lambda$-nucleus or ${\Lambda N}$ potentials are used and the sensitivity of $\Delta B_{\Lambda\Lambda}$ to the interactions is discussed. It is shown that in medium and heavy ${\Lambda\Lambda}$ hypernuclei, $\Delta B_{\Lambda\Lambda}$ is a linear function of $r_{\Lambda}^{-3}$, where $r_\Lambda$ is rms radius of the hyperon orbital. It looks unlikely that it will be possible to extract ${\Lambda\Lambda}$ interaction from the double-$\Lambda$ hypernuclear energies only, the additional information about the $\Lambda$-core interaction, in particular, on $r_{\Lambda}$ is needed.Comment: 11 pages, LaTex, 3 figure

Crossing media boundaries: adaptations and new media forms of the book

t is necessary to continuously review the definition of the book moving from one bound by its material form to one determined by its function as a means of communication. The book’s social function as the high status vehicle for communicating new ideas and cultural expressions is being challenged by sophisticated systems of conveying meaning in other media. In this article, we report on two projects: electronic book (e-book) publication and reader forum for Nature Mage and the transmedia augmented reality (AR) fiction Sherwood Rise, which investigate these issues. Claudio Pires Franco’s work is based on the adaptation of a source work: Duncan Pile’s Nature Mage. The project aims to develop the book from e-book to a fan-produced enhanced digital book. Through this practice-based research, Franco investigates the definitions and classification of the e and i forms of the book and adaptation in new media; the role of the author in creative collaboration with readers through online forums; the extension of the story world through creative collaboration and reader participation while respecting and safeguarding creative properties. One remove from the traditional book, David Miller’s Sherwood Rise, research the user experience with AR to examine narrative problems and explore new storytelling aesthetics. These new media forms define the outer borders of the book system within which content is formed and moulded, and around which society is shaped

The effectiveness of hot water pressurized spray in field conditions to slow the spread of invasive alien species

An array of vectors have been identified that pose a risk of spreading invasive alien species (IAS), from personal protective equipment to large equipment such as vehicles and boats. Biosecurity practices that remove and/or kill IAS reduce the risk of accidental spread. The effectiveness of biosecurity protocols suitable for large equipment is little tested and requires development. One widely-used biosecurity method for large equipment is high-pressure hot water spray machines. This study tests the effectiveness of high-pressure hot water spray to induce mortality in two invasive aquatic plants: floating pennywort (Hydrocotyle ranunculoides) and Australian swamp-stonecrop (Crassula helmsii); and two invasive invertebrates: killer shrimp (Dikerogammarus villosus) and zebra mussel (Dreissena polymorpha) in field conditions. IAS were exposed to hot water spray for a range of durations (5–15 seconds) and from a range of distances (10–30 cm). Further treatments of up to 90 seconds were applied to C. helmsii. Complete survival of D. polymorpha, D. villosus and C. helmsii was seen in all control treatments following exposure to cold water spray. Hot water spray caused complete mortality of D. polymorpha and D. villosus at 10 cm for 15 seconds, demonstrating the effectiveness of the hot water treatment in inducing mortality. However, treatments were less effective when applied at longer distances and shorter durations. In contrast, hot water spray was ineffective in causing mortality in C. helmsii, even at 90 seconds of exposure. Fragmentation and complete mortality was seen in H. ranunculoides following exposure to hot and cold water spray, therefore the pressure of the spray was associated with H. ranunculoides mortality. The use of hot water spray is effective against the aquatic invasive animals tested here, however to ensure complete mortality, the importance of both duration and distance of hot water spray application is highlighted. Hot water spray did cause complete mortality in H. ranunculoides but not in C. helmsii, therefore the need for treatment water containment and safe disposal is paramount to prevent spread of potentially viable propagules

Double Spin Asymmetries A_NN and A_SS at sqrt{s}=200 GeV in Polarized Proton-Proton Elastic Scattering at RHIC

We present the first measurements of the double spin asymmetries A_NN and A_SS at sqrt{s}=200 GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01<|t|<0.03 (GeV/c)^2. The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes phi_2 and phi_4 at small t as well as on the difference Delta(sigma_T) between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.Comment: 13 pages with 3 figures. Final version accepted by Phys. Lett.