Commissioning and First Operation of the Antiproton Decelerator (AD)

The Antiproton Decelerator (AD) is a simplified source of antiprotons which provides low energy antiprotons for experiments, replacing four machines: AC (Antiproton Collector), AA (Antiproton Accumulator), PS and LEAR (Low Energy Antiproton Ring), shutdown in 1996. The former AC was modified to include deceleration and electron cooling. The AD started operation in July 2000 and has since delivered cooled beam at 100 MeV/c (kinetic energy of 5.3 MeV) to 3 experiments (ASACUSA, ATHENA and ATRAP) for 1500 h. The flux (up to 2.5´105pbars /s delivered in short pulses of 330 ns every 110 s) and the quality of the ejected beam are not far from the design specifications. A linear RF Quadrupole Decelerator (RFQD) was commissioned in November 2000 to post-decelerate the beam for ASACUSA from 5.3 MeV to about 15 keV. Problems encountered in converting the fixed energy AC into a decelerating machine will be outlined, and the present status of the AD, including the performance of the cooling systems and the special diagnostics to cope with beams of less than 107 pbars, will be reviewed. Possible future developments will be sketche

Learning through 'prosuming': Insights from media literacy programmes in Asia

10.1177/097172180801300205Science, Technology and Society132259-27

Genomic HIV RNA Induces Innate Immune Responses through RIG-I-Dependent Sensing of Secondary-Structured RNA

Contains fulltext : 108031.pdf (publisher's version ) (Open Access)BACKGROUND: Innate immune responses have recently been appreciated to play an important role in the pathogenesis of HIV infection. Whereas inadequate innate immune sensing of HIV during acute infection may contribute to failure to control and eradicate infection, persistent inflammatory responses later during infection contribute in driving chronic immune activation and development of immunodeficiency. However, knowledge on specific HIV PAMPs and cellular PRRs responsible for inducing innate immune responses remains sparse. METHODS/PRINCIPAL FINDINGS: Here we demonstrate a major role for RIG-I and the adaptor protein MAVS in induction of innate immune responses to HIV genomic RNA. We found that secondary structured HIV-derived RNAs induced a response similar to genomic RNA. In primary human peripheral blood mononuclear cells and primary human macrophages, HIV RNA induced expression of IFN-stimulated genes, whereas only low levels of type I IFN and tumor necrosis factor alpha were produced. Furthermore, secondary structured HIV-derived RNA activated pathways to NF-kappaB, MAP kinases, and IRF3 and co-localized with peroxisomes, suggesting a role for this organelle in RIG-I-mediated innate immune sensing of HIV RNA. CONCLUSIONS/SIGNIFICANCE: These results establish RIG-I as an innate immune sensor of cytosolic HIV genomic RNA with secondary structure, thereby expanding current knowledge on HIV molecules capable of stimulating the innate immune system

CTF3 Design Report: Preliminary Phase

The design of CLIC is based on a two-beam scheme, where the short pulses of high power 30 GHz RF are extracted from a drive beam running parallel to the main beam. The 3rd generation CLIC Test Facility (CTF3) will demonstrate the generation of the drive beam with the appropriate time structure, the extraction of 30 GHz RF power from this beam, as well as acceleration of a probe beam with 30 GHz RF cavities. The project makes maximum use of existing equipment and infrastructure of the LPI complex, which became available after the closure of LEP. In the first stage of the project, the "Preliminary Phase", the existing LIL linac and the EPA ring, both modified to suit the new requirements, are used to investigate the technique of frequency multiplication by means of interleaving bunches from subsequent trains. This report describes the design of this phase

Beam position monitor R&D for keV ion beams

Beams of cooled antiprotons at keV energies shall be provided by the Ultra-low energy Storage Ring (USR) at the Facility for Low energy Antiproton and Ion Research (FLAIR) and the Extra Low ENergy Antiproton ring (ELENA) at CERN's Antiproton Decelerator (AD) facility. Both storage rings put challenging demands on the beam position monitoring (BPM) system as their capacitive pick-ups should be capable of determining the beam position of beams at low intensities and low velocities, close to the noise level of state-of-the-art electronics. In this contribution we describe the design and anticipated performance of BPMs for low-energy ion beams with a focus on the ELENA orbit measurement systems. We also present the particular challenges encountered in the numerical simulation of pickup response at very low beta values. Finally, we provide an outlook on how the implementation of faster algorithms for the simulation of BPM characteristics could potentially help speed up such studies considerably