Superconducting spoke LINAC design as an alternative option for the CERN LINAC4 high energy part

A standard normal-conducting Side Coupled Linac (SCL) has been chosen as a mainline solution for the CERN LINAC4/SPL to accelerate the beam from 90-160/180 MeV. This type of structure is well known and operates at twice the basic frequency (704.4 MHz). Two alternative superconducting solutions with elliptical and triple-spoke cavities have been studied for this energy range. The present note summarizes the beam dynamics calculations in the superconducting triple-spoke linac section analyzing advantages/disadvantages

To the center of cold spot with Planck

The structure of the cold spot, of a non-Gaussian anomaly in the cosmic microwave background (CMB) sky first detected by Vielva et al. is studied using the data by Planck satellite. The obtained map of the degree of stochasticity (K-map) of CMB for the cold spot, reveals, most clearly in 100 GHz band, a shell-type structure with a center coinciding with the minima of the temperature distribution. The shell structure is non-Gaussian at a 4\sigma confidence level. Such behavior of the K-map supports the void nature of the cold spot. The applied method can be used for tracing voids that have no signatures in redshift surveys.Comment: A & A (in press), 4 pages, 5 figures; to match the published versio

Variable-Phase Asynchronous Cyclotron

The conceptual design of a Variable-Phase Asynchronous Cyclotron (VPAC) is describe, which provides longitudinal bunch compression of accelerated proton or ion beams, and thus, permits high current acceleration at higher accelerator efficiency, where the possible beam losses are minimized and the accelerator's mechanical tolerances are relaxed. Beam control is assured by the ability to independently set and vary the acceleration phase and rf voltage amplitude, the inter-cavity harmonic number and the transverse focusing strength, which considerably overcome the space charge effects in each sector and turn of the proposed cyclotron. The new accelerator concept is especially suitable to accelerate intense proton beams up to 800 MeV in energy and average beam current in the 100-mA class. All accelerator elements are based on currently available and feasible technologies. To demonstrate feasibility of design, the detailed calculations and modeling of a 10-turn VPAC prototype for the production of 25.6 MeV, 100 mA proton beam are presented and the key features of the new accelerator concept are discussed.Comment: 15 pages, 10 figures, 1 tabl

Statistical simulations of machine errors for LINAC4

LINAC 4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing LINAC 2 as injector to the Proton Synchrotron Booster and can also operate in the future as the front end of the SPL, a 3.5 GeV Superconductingg Proton Linac. LINAC 4 consists of a Radio-Frequency Quadrupole, a chopper line, a Drift Tube Linac (DTL) and a Cell Coupled DTL all operating at 352 MHz and finally a Side Coupled Linac at 704 MHz. Beam dynamics was studied and optimized performing end-to-end simulations. This paper presents statistical simulations of machine errors which were performed in order to validate the proposed design

Beam Shape and Halo Monitor Study

The Beam Shape and Halo Monitor, designed by Masaki Hori, is the main diagnostic tool for the 3 MeV test stand scheduled in 2008. This detector will be able to measure the transverse halo generated in the RFQ and the Chopper-line and to detect and measure the longitudinal halo composed of the incompletely chopped bunches. Its principle of functioning is the following: H- ions hit a carbon foil and generate secondary electrons with the same spatial distribution than the incoming beam and a current depending on an emission coefficient given by the carbon foil. These electrons are accelerated towards a phosphor screen by an electric field applied between accelerating grids. Once the electrons reach the phosphor screen, they generate light which is transmitted to a CCD camera via optic fibers [1]. It is expected to give a time resolution of 1-2ns and a spatial resolution of 1mm. The first test of the BSHM done with a Laser has shown a spatial resolution bigger than 1cm and the time resolution bigger than 2ns[2]. The purpose of this study is to understand what are the processes which deteriorate the resolution and to show the benefits brought by adding a pre-accelerating grid in the detector

UPR in palmitate-treated pancreatic beta-cells is not affected by altering oxidation of the fatty acid

<p>Abstract</p> <p>Background</p> <p>Elevated levels of lipids are detrimental for beta-cell function and mass. One of the mechanisms of how fatty acids induce apoptosis is development of the unfolded protein response (UPR). It is still far from understood how fatty acids activate the UPR, however.</p> <p>Methods</p> <p>We examined how palmitate-induced activation of the UPR was affected by altering the metabolism of the fatty acid in insulin-secreting INS-1E and MIN6 cell lines and intact human islets. To increase oxidation, we used low glucose (5.5 mM) or AICAR; and to reduce oxidation, we used high glucose (25 mM) or etomoxir. UPR was measured after 3, 24 and 48 hours of palmitate treatment.</p> <p>Results</p> <p>Modulation of palmitate oxidation by either glucose or the pharmacological agents did not affect palmitate-induced UPR activation.</p> <p>Conclusion</p> <p>Our finding suggests that other factors than oxidation of palmitate play a role in the activation of UPR in fatty acid-treated beta-cells.</p

End-to end simulations of LINAC4

Linac4 is a new H- linear accelerator presently studied at CERN. This machine consists of normal-conducting structures operating at 352.2 MHz and 704.4 MHz re-using the RF equipment from the decommissioned LEP collider. It consists of a 95 keV H- source, a 352 MHz RFQ bringing the energy the energy to 3 MeV, a Chopper line, a 352 MHz Drift Tube Linac bringing the energy to 40 MeV, a 352 MHz Coupled Cavity Drift Tube Linac bringing the energy to 90 MeV and a 704 MHz Side Coupled Linac bringing the energy to 160 MeV. Each section is designed and optimized as stand-alone machines for a good transmission and minimum possible emittance growth. End-to-end simulations starting from the RFQ have been carried out in order to validate and compare the multiparticle simulation codes PATH Manager and TRACEWIN used for beam dynamics calculations as well as to perform a global optimization of the structures in the context of a complex machine