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- Bargholtz, Chr., et al.
(författare)
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The WASA detector facility at CELSIUS
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 594:3, s. 339-350
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Tidskriftsartikel (refereegranskat)abstract
- The WASA 4 pi multidetector system, aimed at investigating light meson production in light ion collisions and eta meson rare decays at the CELSIUS storage ring in Uppsala is presented. A unique feature of the system is the use of hydrogen pellets as internal targets for the first time. A detailed description of the design, together with the anticipated and achieved performance parameters are given. (C) 2008 Elsevier B.V. All rights reserved.
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| 5. |
- Hedlund, E., et al.
(författare)
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A new test stand for heavy ion induced gas desorption measurements at TSL
- 2008
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 586:3, s. 377-381
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Tidskriftsartikel (refereegranskat)abstract
- In several experiments at CERN, GSI and BNL it has been found that the lifetime of highly energetic heavy ions in synchrotrons decreases with increasing number of injected ions. This phenomenon occurs due to the collisions of beam ions and residual gas molecules leading to the change of charge of the ions and their loss on the vacuum chamber walls, which in turn cause ion-induced gas desorption and further pressure increase. To gain a deeper understanding of the ion-induced desorption process in the energy range 5-45 MeV/u, a dedicated test stand was built at the end of the K beamline at The Svedberg Laboratory (TSL) in Uppsala, Sweden. The energy range was chosen due to the fact that the injection energy of the heavy ion synchrotron SIS18 at GSI will be 10 MeV/u, and that there are insufficient data in this energy range. A Test Particle Monte-Carlo model of the experimental set-up was build-up, run and analysed for different sample configurations. An important result is that for the same sample material the desorption yield from a flat sample causes a 1.58 times larger pressure increase than that of a tubular sample. A detailed explanation of the set-up is presented.
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| 9. |
- Lehmann, I., et al.
(författare)
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Vacuum predictions and measurements for an internal Pellet Target at a storage ring
- 2008
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Ingår i: Vacuum. - : Elsevier BV. - 0042-207X .- 1879-2715. ; 82:6, s. 645-650
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Tidskriftsartikel (refereegranskat)abstract
- Measurements with low Z targets at internal experiments typically imply a gas load which deteriorates the vacuum of a storage ring. Future experiments need reliable estimates for the expected vacuum conditions in order to design 4π detectors closely surrounding the interaction area. We present a method for the calculation of the resulting vacuum of such a complex system using a Pellet Target. In order to test the method, a vacuum system with diagnostic tools has been set-up and a Pellet Target was operated under realistic conditions. The results for the absolute vacuum agree within factors of two with the expected pressures.
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| 11. |
- Nordhage, Örjan, et al.
(författare)
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Tracked pellets - a way to improve the efficiency of charmonium studies
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 568:2, s. 561-565
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the possibility of tracking individual hydrogen micro-spheres from an internal pellet target. Such a method aims to provide the primary vertex of a reaction to within about 100 mu m, without utilizing any detector response. Apart from background considerations the knowledge of the reaction vertex may be essential for the reconstruction of many physics channels. This is in particular true for the study of the Psi(3770) decay into D-mesons planned at the PANDA detector at the future FAIR facility. Here, the reconstruction of displaced vertices is especially difficult since neutral particles are involved.Studies with a pellet target at The Svedberg Laboratory, Uppsala, show the technical feasibility of a tracking system utilizing fast CCD line-scan cameras. Simulations for the reaction pp -> Psi(3770) -> D+D- prove the large impact such a system would have on the data taking and reconstruction at PANDA.
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| 12. |
- Ward, S. R., et al.
(författare)
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Dorsal transfer of the brachioradialis to the flexor pollicis longus enables simultaneous powering of key pinch and forearm pronation
- 2006
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Ingår i: J Hand Surg [Am]. - : Elsevier BV. - 0363-5023. ; 31:6, s. 993-7
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To show biomechanically that the brachioradialis (BR) muscle can be transferred to restore key pinch and forearm pronation simultaneously. METHODS: Nine fresh-frozen forearms were thawed and instrumented with a custom muscle-tendon excursion jig. Maximum BR muscle-tendon excursion was measured with the wrist and thumb mobile. Muscle-tendon excursion then was measured from 60 degrees of supination to 60 degrees of pronation in 15 degrees increments with the wrist and thumb fixed. Measurements were performed in 3 configurations: the native BR, the BR transferred volarly to the flexor pollicis longus (FPL) tendon, and the BR transferred dorsally (posterior to the radius) through the interosseous membrane to the FPL tendon. Muscle excursion-joint angle data were differentiated to compute pronation/supination moment arms. Two-way analyses of variance and post hoc Tukey tests were used to compare transfer conditions. RESULTS: Maximum muscle excursion was nearly identical when volar and dorsal transfer conditions were compared. When pronation/supination motions were isolated, however, the volar transfer was associated with muscle shortening and small pronation moment arms through 30 degrees +/- 9 degrees of supination. Importantly, the dorsal transfer was associated with muscle shortening and larger pronation moment arms through 28 degrees +/- 10 degrees of pronation, a significant difference of 58.0 degrees +/- 16.0 degrees compared to the traditional volar transfer. CONCLUSIONS: These data suggest that dorsal BR-to-FPL transfers can power key pinch and forearm pronation simultaneously even in the absence of other functional pronators. This transfer can be accomplished without changes to total muscle excursion compared with the traditional volar BR-to-FPL transfer. This result may enable the use of the BR-to-FPL transfer in patients who need key pinch but who lack functional pronation muscle groups (eg, ocular cutaneous 3). As result a larger patient population may benefit from the BR-to-FPL reconstructive procedure.
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