| 1. |
- Ferrari, Arnaud, 1973-, et al.
(författare)
-
Conceptual design of a vacuum window at the exit of the CLIC post-collision line
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, we present a design of the window between the accelerator vacuum and the beam dump at the end of the CLIC post-collision line. We propose to use a thick (1.5 cm) layer of carbon-carbon composite, with a thin (0.2 mm) leaktight foil. The energy deposition and the temperature increase due to the beam impact, as well as the stress levels in the window, are estimated and we show that Aluminium is the most suitable material for the thin foil. At the beam impact, the temperature increase after the passage of a CLIC bunch train is of the order of 1 K and the subsequent (cyclic) thermal stress remains smaller than 1 MPa. As for the (static) mechanical stress, it is about 4 MPa in the beam impact region, and it goes up to 15 MPa near the lateral edges of the window. Still, these constraints are more relaxed than for the LHC dump window.
|
|
| 2. |
- Ferrari, Arnaud, 1973-, et al.
(författare)
-
Design study of the CLIC Injector and Booster Linacs with the 2007 beam parameters
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This note presents new particle tracking studies in the CLIC Injector and Booster Linacs, which accelerate both electrons and positrons, respectively from 200 MeV to 2.42 GeV, prior to their injection into the pre-damping rings, and from 2.42 to 9 GeV, before their transport to the main accelerating linacs.
|
|
| 3. |
- Ferrari, Arnaud, 1973-
(författare)
-
Impact of the new CLIC beam parameters on the design of the post-collision line and its exit window
- 2008
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Following the recent modification of the CLIC beam parameters, we present an updated design of the post-collision line. As a result of the increase of the beamstrahlung photon cone size, the separation of the outgoing beams by the vertical magnetic chicane is more difficult, but still possible. The main changes in the post-collision line design include the implementation of a common dump for the wrong-sign charged particles of the coherent pairs and for the low-energy tails of the disrupted beam, as well as a significant reduction of the overall lattice length (allowing removal of the large refocusing quadrupoles). The thermal and mechanical stresses in the new exit window, 150 m downstream of the interaction point, were computed. We conclude that, despite the recent changes of the CLIC beam parameters and the necessary modifications of the post-collision line and its exit window, their performance is not significantly affected.
|
|
| 4. |
|
|
| 5. |
- Abulaiti, Yiming, et al.
(författare)
-
Technical Design Report for the Phase-II Upgrade of the ATLAS Tile Calorimeter
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This Technical Design Report describes the project to upgrade the ATLAS Tile Calorimeter for the operation at the High Luminosity LHC. The High Luminosity LHC is planned to begin operation in 2026 and to deliver more than ten times the integrated luminosity (up to 4000 fb"^{-1}" of the LHC Runs 1-3 combined. To achieve this integrated luminosity in a reasonable amount of time, an instantaneous luminosity of up to "7.5\times 10^{34} cm^{-2}s^{-1}" is required, corresponding to up to 200 simultaneous pp interactions per bunch crossing. The large luminosity offers the opportunity for a wealth of physics measurements but presents significant challenges to the detector as well as to the trigger and data acquisition systems in the form of increased trigger rates and detector occupancy. This document summarises the requirements and motivations for the Tile Calorimeter upgrade and gives a detailed technical description of the different components. It describes the beam tests with the prototypes in recent years and the plans for the assembly, quality assurance and the integration of the final system. The document also presents the key aspects of project management with an overview of the organisation, the schedule and the cost.
|
|
| 6. |
- Hansson, Johan
(författare)
-
Quantivity?
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)
|
|
| 7. |
- Mohr, Matthias, et al.
(författare)
-
Wind power in forests II : Forest wind
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Sweden has good conditions for wind power. However, most of Sweden (ca. 70%) is covered by forest. Forests decrease wind speeds and create turbulence, something which is not favourable for wind power. Several Swedish wind maps have shown that forests in Nordic countries can be well suited for wind power (e.g. Bergström and Söderberg 2011, Byrkjedal and Åkervik 2009).At the same time, there is uncertainty over wind conditions over forests at very high altitudes (ca. 150 m above ground). How good do wind resource assessment models agree with measurements? How much energy is a wind turbine in forest going to produce and which loads will a wind turbine in forest experience?This project has investigated all these issues. Work was concentrated in the following work packages:Wind resource at very high heightsTurbulence- and wind measurements at very high heights above forestAnalysis of turbulence data from forestsModel simulations with wind flow modelsModel simulations with very-high-resolution weather forecast modelsModel simulations with Large Eddy Simulation (LES) modelsImproved specification of so-called “synthetic turbulence” over forestAnalysis of airborne laser altimeter measurements over forestForest’s effects on wind turbine energy productionLoad simulations for wind turbines over forestWP1 studies how wind speed and direction varies with height over forest (up to ca 150 m above ground and higher up). Several profile relations are studied here. Frequency distributions of wind shear and veer are presented. WP2 describes turbulence and wind measurements that have been carried out within the project at Hornamossen. Moreover, the measurement campaign that was carried out in a line over the Hornamossen-hill within the New European Wind Atlas project is described. WP3 analyses turbulence data from Hornamossen together with turbulence data from Ryningsnäs. Of special interest is how turbulence intensity decreases with height as well as if the IEC-standard class A, B or C for wind turbines is complied with at different heights. WP4 describes the newly developed linearised wind flow model ORFEUS with a dedicated forest module. WP5 describes model simulations with WRF and the MIUU model, their sensitivity for surface roughness and turbulence parameterisations. Mean wind profiles from the models are compared to Hornamossen. WP6 describes LES simulations with Chalmers LES model and WRF-LES. LES-resultats depend to a large degree on how the turbulent vortices are initialised at the inflow boundaries of the LES model. Several different methods for that are described. WP7 describes a new turbulence model (the Segalini & Arnqvist model) that includes atmospheric stability. This is a further development of the IEC turbulence model (=Mann model) for neutral stability. Coherence of turbulent winds as well as phase profiles are other improvements of the IEC model. WP8 describes a new method to compute leaf/needle/plant area density from laser scans of the Swedish forest and how one estimates surface roughness and zero plane displacement from that. The new method is compared with two other methods. Results are also compared with official forest data (“skoglig grunddata”). The effect on the wind profile is also shown. WP9 describes the new methods for estimating AEP from the Power Curve Working Group and the IEC standard for Power Performance Testing. Effects on estimated AEP are shown. A new simple model for calculating turbulence effects on energy production is developed and compared with data from a wind farm. Within WP10 a new generic open-source wind turbine is developed and used for load simulations with aero-elastic simulations. Results show that the new coherence model for turbulence gives much smaller loads than the turbulence model of the IEC standard.For more information on the different parts of the project the reader is referred to the report’s introduction, the ”Summary and Conclusions” of each chapter as well as the overall summary (”Executive Summary”) at the end of the report.
|
|
| 8. |
- Ferretti, Gabriele, 1963, et al.
(författare)
-
Beyond the Standard Model Physics at the HL-LHC and HE-LHC
- 2018
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as 3 ab−1 of data taken at a centre-of-mass energy of 14 TeV, and of a possible future upgrade, the High Energy (HE) LHC, defined as 15 ab−1 of data at a centre-of-mass energy of 27 TeV. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by 20−50% on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics.
|
|
| 9. |
|
|
| 10. |
- Ouahioune, Nedjma, 1999-
(författare)
-
Project Material Physics - MOKE set-up to measure magnetic anisotropy
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Magneto-optical Kerr effect (MOKE) brings out the change in polarization of light reflected from a magnetic material. It is a powerful tool to study magnetic properties of materials among which the anisotropy. Various set-upsoperate in the material physics laboratory based on specific optical configurations. At room temperature, the RT-MOKE set-up uses reversing magnetic fields to measure the hysteresis loops of magnetic materials. Information about a number of important magnetic properties such as the magnetic anisotropy can be extracted from the hysteresis loops. The correlation between configuration of the set-up and reliable results is well established. Therefore, the aim of the project is to improve the system. More precisely, the project focuses on automating the manual adjustments precedinga measurement. The first step consists in learning how to operate the set-up. It is done by performing measurements on anisotropic magnetic samples. The second step is the automation of the analyser’s angle. As a requirement, time of the project is dedicated to learn Lab VIEW. Then, the automation of the analyser’s angle is executed. Finally, the last part is to automate the rotation of the sample as well as the positioning of both the detector and the analyser. The automation described bears the purpose to increase the accuracy especially by fixing reproducibility issues and ensure the settings are less time consuming. In this report, one can find the work carried out from January to May in order to develop the described automation, as part of a Bachelor’s project of 15 credits in material physics.
|
|
