107 research outputs found

    Vacuum Calculations for the LHC Experimental Beam Chambers

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    The vacuum stability is studied for the LHC experimental beam vacuum chambers of ALICE, ATLAS, and CMS. The present baseline design includes sputtered Non-Evaporable Getter (NEG) coating over the whole chamber inner surface providing distributed pumping and an antimultipactor coating. The data are presented for the dominant gas species (H2, CH4, CO and CO2) in a baked system. It results that the distributed pumping is necessary for vacuum stability of CO. Lumped pumping with Sputter Ion Pumps (SIP) is also indispensable for the stability of CH4. The operational constraints with NEG technology are described

    Design Aspects of the RF Contacts for the LHC Beam Vacuum Interconnects

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    The LHC requires a very low longitudinal and transverse beam coupling impedance, in particular at low frequencies. This implies an admissible DC contact resistance of less than 0.1 mΩ\Omega for the RF contacts inside the vacuum bellows which must carry the image current (up to 50 A peak) of the beam at each vacuum chamber interconnect. Technological aspects, measurement methods and test results are presented for the contacts which will be used in the LHC. The modified mechanical design and the justifications for specific choices will be discusse

    Status of the RFQ linac installation and conditioning of the Linear IFMIF Prototype Accelerator

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    Abstract The Radio Frequency Quadrupole (RFQ) linac and 1.6 MW RF power system of the Linear IFMIF Prototype Accelerator (LIPAc) facility in the International Fusion Energy Research Center (IFERC) in Rokkasho (Japan) has been installed and conditioned. During the assembly and tuning process, the RFQ cavity was protected with a temporary tent from the potential deterioration of performance caused by dust. The vacuum in the cavity was improved through the 100 °C baking process of the cavity. The high power test of the 175 MHz RF systems up to 200 kW in CW for each of the eight RF chains was performed for checking its stable output reproducibility in Japan, before connecting 9–3/16 inch coaxial transmission lines from the RF chains to the RF input couplers of the cavity. It was confirmed that the eight RF chains provided the balanced RF power to the single RFQ cavity in-phase using a feedback loop and a synchronization system. The peak power in the cavity achieved 150 kW in the pulsed mode, which corresponds approximately to the required electric field to accelerate proton beam. Such RF conditioning process is ongoing to achieve 600 kW approximately required for deuteron beam commissioning planned in 2018

    Engineering validation for lithium target facility of the IFMIF under IFMIF/EVEDA project

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    The International Fusion Materials Irradiation Facility (IFMIF), presently in the Engineering Validation and Engineering Design Activities (EVEDA) phase was started from 2007 under the frame of the Broader Approach (BA) agreement. In the activities, a prototype Li loop with the world's highest flow rate of 3000L/min was constructed in 2010, and it succeeded in generating a 100mm wide and 25mm thick with a free-surface lithium flow along a concave back plate steadily at a high-speed of 15m/s at 250°C for 1300h. In the demonstration operation it was needed to develop the Li flowing measurement system with precious resolution less than 0.1mm, and a new wave height measuring method which is laser-probe method was developed for measurements of the 3D geometry of the liquid Li target surface. Using the device, the stability of the variation in the Li flowing thickness which is required in the IFMIF specification was ±1mm or less as the liquid Li target, and the result was satisfied with it and the feasibility of the long-term stable liquid Li flow was also verified. The results of the other engineering validation tests such as lithium purification tests of lithium target facility have also been evaluated and summarized

    Health-related quality of life change in patients treated at a multidisciplinary pain clinic

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    Background Multidisciplinary pain management (MPM) is a generally accepted method for treating chronic pain, but heterogeneous outcome measures provide only limited conclusions concerning its effectiveness. Therefore, further studies on the effectiveness of MPM are needed to identify subgroups of patients who benefit, or do not benefit, from these interventions. Our aim was to analyse health-related quality of life (HRQoL) changes after MPM and to identify factors associated with treatment outcomes. Methods We carried out a real world observational follow-up study of chronic pain patients referred to a tertiary multidisciplinary outpatient pain clinic to describe, using the validated HRQoL instrument 15D, the HRQoL change after MPM and to identify factors associated with this change. 1,043 patients responded to the 15D HRQoL questionnaire at baseline and 12 months after the start of treatment. Background data were collected from the pre-admission questionnaire of the pain clinic. Results Fifty-three percent of the patients reported a clinically important improvement and, of these, 81% had a major improvement. Thirty-five percent reported a clinically important deterioration, and 12% had no change in HRQoL. Binary logistic regression analysis revealed that major improvement was positively associated with shorter duration of pain (Peer reviewe
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