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- Abdellaoui, G., et al.
(författare)
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First observations of speed of light tracks by a fluorescence detector looking down on the atmosphere
- 2018
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25(th) of August 2014 from Timmins, Canada. The flight ended successfully after maintaining the target altitude of 38 km for five hours. One part of the mission was a 2.5 hour underflight using a helicopter equipped with three UV light sources (LED, xenon flasher and laser) to perform an inflight calibration and examine the detectors capability to measure tracks moving at the speed of light. We describe the helicopter laser system and details of the underflight as well as how the laser tracks were recorded and found in the data. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. Finally, we present a first reconstruction of the direction of the laser tracks relative to the detector.
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- Kaplan, L. P., et al.
(författare)
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Plan quality assessment in clinical practice: Results of the 2020 ESTRO survey on plan complexity and robustness
- 2022
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Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140. ; 173, s. 254-261
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Plan complexity and robustness are two essential aspects of treatment plan quality but there is a great variability in their management in clinical practice. This study reports the results of the 2020 ESTRO survey on plan complexity and robustness to identify needs and guide future discussions and con-sensus.Methods: A survey was distributed online to ESTRO members. Plan complexity was defined as the mod-ulation of machine parameters and increased uncertainty in dose calculation and delivery. Robustness was defined as a dose distribution's sensitivity towards errors stemming from treatment uncertainties, patient setup, or anatomical changes.Results: A total of 126 radiotherapy centres from 33 countries participated, 95 of them (75%) from Europe and Central Asia. The majority controlled and evaluated plan complexity using monitor units (56 centres) and aperture shapes (38 centres). To control robustness, 98 (97% of question responses) photon and 5 (50%) proton centres used PTV margins for plan optimization while 75 (94%) and 5 (50%), respectively, used margins for plan evaluation. Seventeen (21%) photon and 8 (80%) proton centres used robust opti-misation, while 10 (13%) and 8 (80%), respectively, used robust evaluation. Primary uncertainties consid-ered were patient setup (photons and protons) and range calculation uncertainties (protons). Participants expressed the need for improved commercial tools to control and evaluate plan complexity and robust-ness.Conclusion: Clinical implementation of methods to control and evaluate plan complexity and robustness is very heterogeneous. Better tools are needed to manage complexity and robustness in treatment plan-ning systems. International guidelines may promote harmonization.(c) 2022 The Authors. Published by Elsevier B.V. Radiotherapy and Oncology 173 (2022) 254-261 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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- Matis, H. S., et al.
(författare)
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The BRAN luminosity detectors for the LHC
- 2017
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 848, s. 114-126
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the several phases which led, from the conceptual design, prototyping, construction and tests with beam, to the installation and operation of the BRAN (Beam RAte of Neutrals) relative luminosity monitors for the LHC. The detectors have been operating since 2009 to contribute, optimize and maintain the accelerator performance in the two high luminosity interaction regions (IR), the IR1 (ATLAS) and the IR5 (CMS). The devices are gas ionization chambers installed inside a neutral particle absorber 140 m away from the Interaction Points in IR1 and IR5 and monitor the energy deposited by electromagnetic showers produced by high-energy neutral particles from the collisions. The detectors have the capability to resolve the bunch-by-bunch luminosity at the 40 MHz bunch rate, as well as to survive the extreme level of radiation during the nominal LHC operation. The devices have operated since the early commissioning phase of the accelerator over a broad range of luminosities reaching 1.4×1034 cm−2 s−1 with a peak pileup of 45 events per bunch crossing. Even though the nominal design luminosity of the LHC has been exceeded, the BRAN is operating well. After describing how the BRAN can be used to monitor the luminosity of the collider, we discuss the technical choices that led to its construction and the different tests performed prior to the installation in two IRs of the LHC. Performance simulations are presented together with operational results obtained during p-p operations, including runs at 40 MHz bunch rate, Pb-Pb operations and p-Pb operations.
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- Perez-Tomas, A, et al.
(författare)
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Schottky versus bipolar 3.3 kV SiC diodes
- 2008
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Ingår i: SEMICONDUCTOR SCIENCE AND TECHNOLOGY. - : IOP Publishing. - 0268-1242 .- 1361-6641. ; 23:12, s. 125004-
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Tidskriftsartikel (refereegranskat)abstract
- A comparative study of the electrical characteristics of 3.3 kV SiC Schottky barrier (SBD), junction bipolar Schottky (JBS) and PiN diodes is presented. 3.3 kV class 4H-SiC SBD, JBS and PiN diodes have been fabricated with an analogous technology process on similar epi wafers. Diodes have been characterized in forward, reverse and switching mode in the 25 degrees C - 300 degrees C temperature range. The optimum performance of the diodes depends on the adequate use of the unipolar or bipolar advantages and is established by the final application specifications. In this respect, a reverse recovery charge versus on-resistance diagram for different current densities is also presented. DC stress tests have been performed to investigate the forward voltage drift, related to the formation of stacking faults, during the bipolar mode of operation.
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