Two years of AD operation: Experience and progress

The antiproton decelerator (AD) has been running successfully for physics for the past two years. After the end of the commissioning period [1] that finished in 2000, the machine has gradually been improved. The main efforts were concentrated on increasing the beam intensity, reducing the cycle length and improving the machine stability. The intensity of the injected beam has been significantly increased due to a higher beam intensity from the PS complex and also due to increased transverse acceptances in the AD machine. The beam losses during deceleration were reduced from 30-40 % down to a few percent, mainly due to improvements of the operation of the deceleration RF cavity. Altogether these improvements increased the intensity of the ejected beam by a factor of two. Improvements of the electron cooling were followed by a reduction of emittances and cycle duration (about 15%). Progress in beam diagnostics now allows the monitoring of the machine performance during the whole cycle. The stability of the machine at the ejection momentum 100 MeV/c remains a crucial point and the identification of the causes of fluctuations in the ejected beam parameters are now under investigation

CERN Proton Synchrotron Complex High-Level Controls Renovation

After a detailed study of the Proton Synchrotron (PS) complex requirements by experts of CERN controls & operation groups, a proposal to develop a new system, called Injector Controls Architecture (InCA), was presented to and accepted by the management late 2007. Aiming at the homogenisation of the control systems across CERN accelerators, InCA is based on components developed for the Large Hadron Collider (LHC) but also new components required to fulfil operation needs. In 2008, the project was in its elaboration phase and we successfully validated its architecture and critical use-cases during several machine development sessions. After description of the architecture put in place and the components used, this paper describes the planning approach taken combining iterative development phases with deployment in operation for validation sessions

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

ELENA, a preliminary cost and feasibility study

To produce dense pbar beams at very low energies (100-200 keV), a small decelerator ring could be built and installed between the existing AD ring and the experimental area. Phase-space blowup during deceleration would be compensated by electron cooling in order to obtain final emittances comparable to the 5MeV beam presently delivered by the AD. This report describes preliminary machine parameters and layout of ELENA and also gives an approximate estimate of cost and manpower needs

IONS FOR LHC: STATUS OF THE INJECTOR CHAIN

The LHC will, in addition to proton runs, be operated with Pb ions and provide collisions at energies of 5.5 TeV per nucleon pair, i.e. more than 1.1 PeV per event, to experiments. The transformation of CERN's ion injector complex (Linac3-LEIR-PS-SPS) to allow collision of ions in LHC in 2008 is well under way. The status of these modifications and the latest results of commissioning will be presented. The remaining challenges are reviewed

Ions for LHC: Towards Completion of the Injector Chain

The commissioning of CERN's ion injector complex [1] to allow 1.1 PeV collisions of ions in LHC is well under way. After the Low Energy Ion Ring (LEIR) in 2005 [2] and the Proton Synchrotron (PS) in 2006 [3], the Super Proton Synchrotron (SPS) has now been commissioned with the 'Early' ion beam, which should give a luminosity of $5×10^{25}cm^{-2}s^{-1}$ in the LHC. This paper summarizes the operation in 2007 of all the machines involved in the ion injection chain

Mitochondrial abnormalities and low grade inflammation are present in the skeletal muscle of a minority of patients with amyotrophic lateral sclerosis; an observational myopathology study

BACKGROUND Amyotrophic lateral sclerosis (ALS) is a primary progressive neurodegenerative disease characterised by neuronal loss of lower motor neurons (in the spinal cord and brainstem) and/or upper motor neurons (in the motor cortex) and subsequent denervation atrophy of skeletal muscle. AIM A comprehensive examination of muscle pathology from a cohort of clinically confirmed ALS patients, including an investigation of inflammation, complement activation, and deposition of abnormal proteins in order to compare them with findings from an age-matched, control group. MATERIAL AND METHODS 31 muscle biopsies from clinically confirmed ALS patients and 20 normal controls underwent a comprehensive protocol of histochemical and immunohistochemical stains, including HLA-ABC, C5b-9, p62, and TDP-43. RESULTS Neurogenic changes were confirmed in 30/31 ALS cases. In one case, no neurogenic changes could be detected. Muscle fibre necrosis was seen in 5/31 cases and chronic mononuclear inflammatory cell infiltration in 5/31 (2 of them overlapped with those showing muscle necrosis). In four biopsies there was an increase in the proportion of cytochrome oxidase (COX) negative fibres (2-3%). p62 faintly stained cytoplasmic bodies in eight cases and none were immunoreactive to TDP-43. CONCLUSION This large series of muscle biopsies from patients with ALS demonstrates neurogenic atrophy is a nearly uniform finding and that mild mitochondrial abnormalities and low-grade inflammation can be seen and do not rule out the diagnosis of ALS. These findings could lend support to the notion that ALS is a complex and heterogeneous disorder

C9orf72 Poly(PR) Mediated Neurodegeneration Is Associated With Nucleolar Stress

The ALS/FTD-linked intronic hexanucleotide repeat expansion in the C9orf72 gene is aberrantly translated in the sense and antisense directions into dipeptide repeat proteins, among which poly proline-arginine (PR) displays the most aggressive neurotoxicity in-vitro and in-vivo. PR partitions to the nucleus when heterologously expressed in neurons and other cell types. We show that by lessening the nuclear accumulation of PR, we can drastically reduce its neurotoxicity. PR strongly accumulates in the nucleolus, a nuclear structure critical in regulating the cell stress response. We determined that, in neurons, PR caused nucleolar stress and increased levels of the transcription factor p53. Downregulating p53 levels also prevented PR-mediated neurotoxicity both in in-vitro and in-vivo models. We investigated if PR could induce the senescence phenotype in neurons. However, we did not observe any indications of such an effect. Instead, we found evidence for the induction of programmed cell death via caspase-3 activation