Transfer Line Studies from LINAC4 to the PS Booster: Green Field Option

Linac4 is a normal conducting H- linac, which is currently under study at CERN as upgrade to the present LHC injectors chain in view of intensifying the proton flux available for the CERN accelerator complex and eventually attain LHC ultimate luminosity goals. The new linac is designed to accelerate a 65 mA H- ion beam from 45 keV up to 160 MeV for charge-exchange injection into the CERN Proton Synchrotron Booster, thus overcoming the space charge limitations of the present injection mechanism at 50 MeV, which represent the main obstacle to obtaining higher beam brightness into the PS. A transfer line is being planned to transport the beam from the end of Linac4 to the PSB: a solution corresponding to a siting of the linac in the existing PS South Hall was initially studied [1] but later discarded in favour of a new "green field" arrangement of a whole complex of new machines (including the SPL and PS2) at CERN. The present note outlines this latest layout and presents the results of the relative beam dynamics studies

Study of a spectrometer line for the Linac4 diagnostics movable bench

movable diagnostics bench is currently being designed as part of the Linac4 commissioning plan to characterise the H-beam at the exit of each DTL tank. A spectrometer line has been proposed for installation on the bench to allow performing measurements of the beam energy spread with a slit/dipole/monitor technique. A layout for this diagnostics line is here proposed together with the results of beam dynamics studies to evaluate the resolution achievable and the measurement reach

Transfer Line Studies from LINAC4 to the PS Booster: "South Hall" Option

Linac4 is a new normal conducting H- linac, which is currently under study at CERN as upgrade to the present LHC injectors chain in view of intensifying the proton flux available for the CERN accelerator complex and eventually attain LHC ultimate luminosity goals. The new linac is designed to accelerate a 65 mA H- ion beam from 3 MeV up to 160 MeV for charge-exchange injection into the CERN Proton Synchrotron Booster, thus overcoming the space charge limitations of the present injection mechanism at 50 MeV, which represent the main obstacle to obtaining higher beam brightness into the PS. A new transfer line is also being planned to transport the beam from the end of Linac4 to the PSB and the present paper outlines one of the proposed layouts and gives the status of the beam dynamics studies for this solution

Updated layout of the LINAC4 transfer line to the PS Booster (Green Field Option)

At the time of defining the site of Linac4 and its integration in the complex of existing infrastructure at CERN (together with the plans for a future Superconducting Proton Linac), a series of radiation protection issues emerged that have since prompted a revision of the Linac4 to PSB transfer line layout, as was described in the document ABâNoteâ2007â037. For radiological safety reasons the distance between the planned SPL tunnel and the basement of building 513 had to be increased, and this led to the decision to lower the Linac4 machine by 2.5m. A vertical ramp was consequently introduced in the transfer line to raise the beam at the same level of LINAC2/PSB for connection to the existing transfer line. A series of error study runs has been carried out on the modified layout to have an estimate of the losses induced by quadrupole alignment and field errors. The two worst cases of each error family have been used as case studies to test the efficiency of possible steering strategies in minimizing beam losses and machine activation. The new layout and beam dynamics issues plus the results of the error and steering studies are discussed in this note

Reproductive aspects of the velvet belly lantern shark Etmopterus spinax (Condrichthyes: Etmopteridae), from the central western Mediterranean sea. Notes on gametogenesis and oviducal gland microstructure.

In this paper, the reproductive biology of the velvet belly lanternshark Etmopterus spinax was analyzed in Sardinian waters (central western Mediterranean). This species was sexually dimorphic with females growing to a larger size than males. Marked sexual dimorphism in size was also observed along the vertical gradient. Histological analysis of gonads was very useful in assigning macroscopical maturity stages. The investigation on the microstructure of oviducal gland (OG) highlighted four morphofunctional zones with mucous and/or proteic secretions according to the zone and to their specific functions and development. Sperm in the OG was found for the first time in E. spinax. The localization of sperm storage tubules deeper in OG suggested long-term sperm storage, which is in agreement with the long reproductive cycle described. This species matured late, specifically at 80.7% and 79% at the maximum observed size for females and males respectively. Mature specimens were found throughout the year with pregnant females observed in winter and autumn. A low fecundity was observed with a mean ovarian fecundity of 16.5 mature follicles

Once daily nebulized beclomethasone is effective in maintaining pulmonary function and improving symptoms in asthmatic children

Background and Aim. Compliance with long-term inhaled therapy in asthma is often poor, but it is likely to be improved with a simplified administration, once daily.The present study was designed to assess whether, in childhood asthma, a single dose of nebulized beclomethasone dipropionate once daily was as effective and safe as the same total daily dose administered twice daily. Methods. Asthmatic children, not treated with inhaled steroids for at least a month preceding the study and using short-acting bronchodilators more than once a week were enrolled in a double-blind, double dummy, randomised, multicentric study. After a two week run-in period on nebulised twice daily 400 mcg beclomethasone dipropionate, patients were randomly assigned to twelve weeks of treatment with 800 mcg nebulised beclomethasone dipropionate daily, either in single dose (o.d. group) or divided into two 400 mcg doses (b.i.d. group). Results. 65 children (mean age 8.6 years, mean FEV1 81% of predicted), were valuable for intention to treat. During the run-in period, a significant improvement in FEV1, FVC, morning and evening PEF values and clinical scores was observed. Children then entered the randomised trial: 32 were included in the o.d. group and 33 in the b.i.d. group. During the twelve week treatment period, the observed improvement in pulmonary function parameters was maintained in both treatment groups. Morning and evening PEF showed a progressive slight increase as well as PEF diurnal variability showed a progressive reduction in the two treatment groups during the whole study period without reaching statistical significance. Moreover, in both treatment groups a similar progressive increase in symptom free nights and days and in the percentage of children achieving total asthma symptoms control was detected. Finally, no significant changes in urinary cortisol/creatinine ratio were observed throughout the study period and between groups. Conclusions. A daily dose of 800 mcg of beclomethasone, administered for twelve weeks with a nebuliser either once or twice daily provide similar efficacy in maintaining pulmonary function and symptoms of asthmatic children, with a good tolerability profile

Assessing thornback ray growth pattern in different areas of Western-Central Mediterranean Sea through a Multi-Model Inference analysis

The lack of information on age validation often affects ageing studies in cartilaginous fish, even in the most common species. Recently, the annual growth band deposition pattern has been directly validated for thornback ray in the Mediterranean Basin, thus providing a highly reliable protocol for age reading. In this regard, taking advantage of this new information, the present study aims to investigate this species growth for the first time over a wide area of the Western and Central Mediterranean Sea, involving four different FAO geographic sub-areas. In order to provide an accurate description of the species growth, different models were fitted to the age-length data obtained from the observation of vertebral centra thin sections. A total of 720 specimens were analysed (358 females and 362 males) with total length ranging between 11.5 and 86.4 cm. The corrected Akaike's Information criterion (AICc) indicated, among the tested models, the three-parameter von Bertalanffy function as the most robust in describing the species growth. Growth modelling outcomes revealed the thornback rays as capable of growing relatively fast during the first years; the growth rate gradually slows down allowing maximum sizes of about 90–100 cm in total length to be reached. Significant discrepancies in the growth pattern were found between sexes in all investigated areas with the only exception being in the Northern Tyrrhenian Sea. Differences in growth patterns were observed between areas, specifically in the estimated growth rate of the species for each sub-region. The present study, confirmed the importance of the availability of a validated ageing protocol and testing multiple growth models. Moreover, our results highlighted the urgent need to investigate a species growth in a wide geographic area, searching also for possible differences at sub-region level. Providing this information could indeed allow eventual management plans to be adapted to the exact growth pattern that the species exhibit in the region, in this way increasing their effectiveness

Linac4 Beam Characterization before Injection into the CERN PS Booster

Construction work for the new CERN linear accelerator, Linac4, started in October 2008. Linac4 will replace the existing Linac2 and provide an H− beam at 160 MeV (as opposed to the present 50 MeV proton beam) for injection into the CERN PS Booster (PSB). The charge-exchange H− injection combined with the higher beam energy will allow for an increase in beam brightness required for reaching the ultimate LHC luminosity. Commissioning of Linac4 and of the transfer line to the PSB is planned for the last quarter of 2012. Appropriate beam instrumentation is foreseen to provide transverse and longitudinal beam characterization at the exit of Linac4 and in two dedicated measurement lines located before injection into the PSB. A detailed description of the diagnostics set, especially of spectrometer and emittance meter, and the upgrade of the measurement lines for Linac4 commissioning and operation is presented

Measurements of heavy ion beam losses from collimation

The collimation efficiency for Pb ion beams in the LHC is predicted to be lower than requirements. Nuclear fragmentation and electromagnetic dissociation in the primary collimators create fragments with a wide range of Z/A ratios, which are not intercepted by the secondary collimators but lost where the dispersion has grown sufficiently large. In this article we present measurements and simulations of loss patterns generated by a prototype LHC collimator in the CERN SPS. Measurements were performed at two different energies and angles of the collimator. We also compare with proton loss maps and find a qualitative difference between Pb ions and protons, with the maximum loss rate observed at different places in the ring. This behavior was predicted by simulations and provides a valuable benchmark of our understanding of ion beam losses caused by collimation.Comment: 12 pages, 20 figure