Static Heat Loads in the LHC Arc Cryostats: Final Assessment

This note presents the final assessment of the static heat loads in the LHC arc cryostats, using different experimental methods during the first commissioning period in 2007. This assessment further develops and completes previous estimates made during the commissioning of sector 7_8 [1]. The estimate of the helium inventory, a prerequisite for the heat load calculation, is also presented. Heat loads to the cold mass are evaluated from the internal energy balance during natural as well as powered warm-ups of the helium baths in different subsector. The helium inventory is calculated from the internal energy balance during powered warm-ups and matched with previous assessments. Furthermore, heat loads to the thermal shield are estimated from the non-isothermal cooling of the supercritical helium in line E. The comparison of measured heat loads with previous estimates and with budgeted values is then presented, while their correlation with some important parameters like insulation vacuum pressure and some heat interception temperatures is proposed and discussed

Assessment of Static Heat Loads in the LHC Arc, from the Commissioning of Sector 7-8

This note presents first estimates of the static heat loads in the LHC arc cryostats, evaluated experimentally during the commissioning of sector 7-8 in April 2007. Heat loads to the thermal shielding are estimated from the non-isothermal cooling of the supercritical helium in line E, while heat loads to the 1.9K level of the cold masses are estimated from the internal energy balance during a natural warm-up of the sector in the absence of active cooling. A comparison of the measured heat loads with the budgeted heat loads is then presented and discussed

Calculation of Helium Inventory in LHC Arcs from Geometry and Comparison with Observations

This report estimates the helium inventory inside the 1.9K cryogenic circuit of the LHC arcs. The assessment is based on geometrical considerations obtained from the construction files of the cold masses and its result is compared with test results and the specified design value

Conceptual design of superferric magnets for PS2

We analyze feasibility and cost of a superferric magnet design for the PS2. Specifically, we provide the conceptual design of dipole and quadrupoles, including considerations on cryogenics and powering. The magnets have warm iron yoke, and cryostated superconducting coils embedded in the magnet, which reduces AC loss at cryogenic temperature. The superconductor has large Operating margin to endure beam loss and operating loads over a long period of time. Although conservative, and without any critical dependence on novel technology developments, this superconducting option appears to be attractive as a low-power alternative to the normal-conducting magnets that are the present baseline for the PS2 design. In addition it provides flexibility in the selection of flat-top duration at no additional cost. This study is the conclusion of the conceptual design work started within the scope of the CARE HHH-AMT activities, following inputs from the workshops ECOMAG and LUMI-06, and finally spurred by the recent discussions on the opportunity of an R&D for the PS2 magnets

Fast cycled superconducting magnets for the upgrade of the LHC injector complex

An upgrade of the LHC injection chain, and especially the sequence of PS and SPS, up to an extraction energy of 1 TeV, is one of the steps considered to improve the performance of the whole LHC accelerator complex. The magnets for this upgrade require central magnetic field from 2 T (for a PS upgrade) to 4.5 T (for an SPS upgrade), and field ramp rate ranging from 1.5 to 2.5 T/s. In this paper we discuss under which conditions superconducting magnets are attractive in this range of operating field and field ramp-rate, and we list the outstanding issues to be adddressed by a dedicated R&D

Conceptual Design of Superferric Magnets for PS2

We analyze feasibility and cost of a superferric magnet design for the PS2, the 50 GeV ring that should replace the PS in the CERN injector chain. Specifically, we provide the conceptual design of dipole and quadrupoles, including considerations on cryogenics and powering. The magnets have warm iron yoke, and cryostated superconducting coils embedded in the magnet, which reduces AC loss at cryogenic temperature. The superconductor has large operating margin to endure beam loss and operating loads over a long period of time. Although conservative, and without any critical dependence on novel technology developments, this superconducting option appears to be attractive as a low-power alternative to the normal-conducting magnets that are the present baseline for the PS2 design. In addition it provides flexibility in the selection of flat-top duration at no additional cost

Active transcriptomic and proteomic reprogramming in the C-elegans nucleotide excision repair mutant xpa-1

Peer reviewe

Different strategies for mechanical VENTilation during CardioPulmonary Bypass (CPBVENT 2014): Study protocol for a randomized controlled trial

Background: There is no consensus on which lung-protective strategies should be used in cardiac surgery patients. Sparse and small randomized clinical and animal trials suggest that maintaining mechanical ventilation during cardiopulmonary bypass is protective on the lungs. Unfortunately, such evidence is weak as it comes from surrogate and minor clinical endpoints mainly limited to elective coronary surgery. According to the available data in the academic literature, an unquestionable standardized strategy of lung protection during cardiopulmonary bypass cannot be recommended. The purpose of the CPBVENT study is to investigate the effectiveness of different strategies of mechanical ventilation during cardiopulmonary bypass on postoperative pulmonary function and complications. Methods/design: The CPBVENT study is a single-blind, multicenter, randomized controlled trial. We are going to enroll 870 patients undergoing elective cardiac surgery with planned use of cardiopulmonary bypass. Patients will be randomized into three groups: (1) no mechanical ventilation during cardiopulmonary bypass, (2) continuous positive airway pressure of 5 cmH2O during cardiopulmonary bypass, (3) respiratory rate of 5 acts/min with a tidal volume of 2-3 ml/Kg of ideal body weight and positive end-expiratory pressure of 3-5 cmH2O during cardiopulmonary bypass. The primary endpoint will be the incidence of a PaO2/FiO2ratio <200 until the time of discharge from the intensive care unit. The secondary endpoints will be the incidence of postoperative pulmonary complications and 30-day mortality. Patients will be followed-up for 12 months after the date of randomization. Discussion: The CPBVENT trial will establish whether, and how, different ventilator strategies during cardiopulmonary bypass will have an impact on postoperative pulmonary complications and outcomes of patients undergoing cardiac surgery. Trial registration: ClinicalTrials.gov, ID: NCT02090205. Registered on 8 March 2014