| 1. |
- Filippi, F., et al.
(författare)
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Plasma density profile reconstruction of a gas cell for Ionization Induced Laser Wakefield Acceleration
- 2023
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 18:5
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Tidskriftsartikel (refereegranskat)abstract
- Laser-driven plasma wakefields can provide hundreds of MeV electron beam in mm-range distances potentially shrinking the dimension of the actual particle accelerators. The plasma density plays a fundamental role in the control and stability of the acceleration process, which is a key development for the future electron injector proposed by EuPRAXIA. A gas cell was designed by LPGP and LIDYL teams, with variable length and backing pressure, to confine the gas and tailor the gas density profile before the arrival of the laser. This cell was used during an experimental campaign with the multi TW-class laser at the Lund Laser Centre. Ionization assisted injection in a tailored density profile is used to tune the electron beam properties. During the experiment, we filled the gas cell with hydrogen mixed with different concentration of nitrogen. We also varied the backing pressure of the gas and the geometrical length of the gas cell. We used a transverse probe to acquire shadowgraphic images of the plasma and to measure the plasma electron density. Methods and results of the analysis with comparisons between shadowgraphic and interferometric images will be discussed.
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| 2. |
- Löfquist, L, et al.
(författare)
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Fixed prosthodontics in adults in Jönköping, Sweden in 1983 and 1993 : An epidemiological study of prevalence and choice of material.
- 2000
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Ingår i: Swedish Dental Journal. - 0347-9994. ; 24:3, s. 93-103
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to assess the prevalence of fixed prostheses, i.e. single crowns and fixed partial dentures, in adults 20-80 years old in two cross-sectional studies carried out in 1983 and 1993 and to analyse whether the choice of material for fixed prostheses had changed during this time period. The material comprised 586 and 593 individuals. A descriptive analysis of number of individuals with fixed prostheses was made concerning the number of crowns and pontics, the distribution in the jaws, and the materials used. The prevalence of individuals with fixed prostheses was shown to increase with age both in 1983 and 1993. In 1993 the number of individuals with fixed prostheses was slightly lower than in 1983 (44 and 48 percent respectively). There was no difference according to gender. The proportion of individuals with fixed prostheses was lower or almost unchanged in the 20-, 30-, 40-, 50-, 60-, and 80-year-olds in 1993 compared to 1983. In the 70-year-olds, however, the proportion of individuals with fixed prostheses was considerably higher in 1993 compared to 1983. Most individuals with fixed prostheses had a small number of crowned teeth, and about half of the individuals had not more than four crowned teeth. Likewise most individuals with pontics had a small number of pontics. The distributions of crowned teeth and pontics in the jaws were similar in 1983 and 1993. Pontics and crowns were more frequent in the upper than in the lower jaw. Crowns made of porcelain or metal ceramic had increased by 1993 in the 30-80 year age groups, and the study thus confirms general clinical experience that porcelain and metal ceramic are more often the materials of choice in fixed prosthodontics in adults today.
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