| 1. |
- Assmann, R. W., et al.
(författare)
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EuPRAXIA Conceptual Design Report
- 2020
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 229:24, s. 3675-4284
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Tidskriftsartikel (refereegranskat)abstract
- This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facility within 8—10 years. © 2020, The Author(s).
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| 2. |
- Cantono, Giada, et al.
(författare)
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Laser-driven proton acceleration from ultrathin foils with nanoholes
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Structured solid targets are widely investigated to increase the energy absorption of high-power laser pulses so as to achieve efficient ion acceleration. Here we report the first experimental study of the maximum energy of proton beams accelerated from sub-micrometric foils perforated with holes of nanometric size. By showing the lack of energy enhancement in comparison to standard flat foils, our results suggest that the high contrast routinely achieved with a double plasma mirror does not prevent damaging of the nanostructures prior to the main interaction. Particle-in-cell simulations support that even a short scale length plasma, formed in the last hundreds of femtoseconds before the peak of an ultrashort laser pulse, fills the holes and hinders enhanced electron heating. Our findings reinforce the need for improved laser contrast, as well as for accurate control and diagnostics of on-target plasma formation.
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| 3. |
- Permogorov, Alexander, et al.
(författare)
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Effects of pulse chirp on laser-driven proton acceleration
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Optimisation and reproducibility of beams of protons accelerated from laser-solid interactions require accurate control of a wide set of variables, concerning both the laser pulse and the target. Among the former ones, the chirp and temporal shape of the pulse reaching the experimental area may vary because of spectral phase modulations acquired along the laser system and beam transport. Here, we present an experimental study where we investigate the influence of the laser pulse chirp on proton acceleration from ultrathin flat foils (10 and 100 nm thickness), while minimising any asymmetry in the pulse temporal shape. The results show a ± 10 % change in the maximum proton energy depending on the sign of the chirp. This effect is most noticeable from 10 nm-thick target foils, suggesting a chirp-dependent influence of relativistic transparency.
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| 4. |
- Rajan, Gita, et al.
(författare)
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A One-Session Treatment of PTSD After Single Sexual Assault Trauma. A Pilot Study of the WONSA MLI Project : A Randomized Controlled Trial
- 2020
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Ingår i: Journal of Interpersonal Violence. - : SAGE Publications. - 0886-2605 .- 1552-6518. ; 37:9-10, s. NP6582-NP6603
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Tidskriftsartikel (refereegranskat)abstract
- Sexual abuse is a crime with devastating health consequences. Accessible, acceptable and affordable treatment of PTSD after sexual abuse is important. In this pilot study, a one-session PTSD treatment and a modified perspective to PTSD treatment is introduced. The aim of the study was to test the efficacy of one session of Modified Lifespan Integration (MLI) on reduction of symptoms of PTSD in individuals with PTSD after one sexual assault. This was a single-center, individually randomized waitlist-controlled treatment study with 1:1 allocation, with the intervention of one 90 - 140 minutes session of MLI and with post-treatment follow-up at 3 weeks (time point two). All participants were females, mean age 24, with PTSD symptoms after one sexual assault during the past 5 years. Exclusion criteria were poor understanding of Swedish, multiple traumas, active substance abuse, active psychosis, ADHD, or autism spectrum disorder. Of 135 interested participants, 38 were finally included, 36 completed baseline measures and were included in the intent to treat analyses and 33 were analyzed per protocol. The primary outcome was the difference between the two trial arms in mean PTSD symptoms as measured by the Impact of Event Scale Revised (IES-R) at time point two. In the intervention arm, 72% no longer scored PTSD in per-protocol analysis, compared to 6% in the waiting list arm. IES-R scores were on average halved in the intervention arm (F=21.37, P<0.001), but were essentially unchanged in the waiting list arm. No adverse effects or drop-outs were seen. One session of Modified Lifespan Integration was an effective treatment with a low drop-out rate for females aged 15-65 with PTSD after one sexual assault. Provided that this result can be replicated, MLI should be offered to these patients in clinical settings. Registration number NCT03141047 was given 03/25/2016 at ClinicalTrials.gov
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| 5. |
- Rajan, Gita, et al.
(författare)
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Delayed healthcare access among victims of sexual abuse, understood through internal and external gatekeeping mechanisms
- 2021
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Ingår i: Nordic Journal of Psychiatry. - : Informa UK Limited. - 0803-9488 .- 1502-4725. ; 75:5, s. 370-377
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Sexual abuse is associated with severe health consequences, and the European Union has, through the Istanbul Convention, urged its member countries to provide specialist care for victims of sexual abuse.AIM: This aim of this study was to investigate patient- and abuse-related characteristics among patients seeking help at a specialist clinic in Sweden, with focus on disclosure, mental health and appropriate healthcare access.METHODS: This is a descriptive study where journal data from 100 consecutive patients January 2017 to February 2018 were analyzed. All adult individuals (women n = 80, men n = 8) who had taken part in the standardized semi-structured intake interview at the clinic were included (n = 88).RESULTS: At admission, mean age was 40.3 (SD 11.9), mean number of psychiatric diagnoses 6.3 (2.6), and 93% of the patients scored above cut-off (≥34) on IES-R for PTSD. A majority of the patients (87%) had been exposed to childhood sexual abuse (CSA), and mean time to first disclosure was 15.9 (SD 15.3) years. In total, 82% of the patients had, despite disclosure, experienced difficulties accessing appropriate healthcare before coming to the specialist clinic.CONCLUSION: Adult victims of sexual abuse have difficulties accessing appropriate healthcare. This constitutes a gender-based equality problem. A model of gatekeeping mechanisms with two dimensions (external and internal) and three categories (Competence related, Organizational and Emotional) is proposed to understand these difficulties.
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| 6. |
- Rajan, Gita, et al.
(författare)
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Health care consumption and psychiatric diagnoses among adolescent girls 1 and 2 years after a first-time registered child sexual abuse experience : a cohort study in the Stockholm Region
- 2021
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Ingår i: European Child and Adolescent Psychiatry. - : Springer Nature. - 1018-8827 .- 1435-165X. ; 30, s. 1803-1811
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Tidskriftsartikel (refereegranskat)abstract
- Child sexual abuse (CSA) is a crime against human rights with severe health consequences, and suicidal actions, stress, eating disorders, and borderline disorder are common among survivors of CSA. The objective of this study was to analyze how health care consumption patterns developed among adolescent girls in the Stockholm Region, Sweden, 1 and 2 years after the first registration of CSA experience appeared in their medical record, as compared to age-matched controls without such registration. In this cohort study, number of healthcare visits, comorbidities, and prescribed drugs were collected through the Stockholm Region administrative database (VAL), for girls age 12-17 with registration of CSA experience in their medical record (n = 519) and age-matched controls (n = 4920) between 2011 and 2018. Healthcare consumption patterns remained higher among the girls with a registered CSA experience compared to the controls, both 1 and 2 years after the first CSA experience registration. Highest odds ratios (ORs) were found for suicide attempts [OR 26.38 (12.65-55.02) and 6.93 (3.48-13.49)]; stress disorders [25.97 (17.42-38.69) and 15.63 (9.82-24.88)]; psychosis [OR 19.39 (1.75-214.13) and 9.70 (1.36-68.95)], and alcohol abuse [OR 10.32 (6.48-16.44) and 6.09 (1.98-18.67)], 1 and 2 years, respectively, after the first CSA experience registration. The drug prescriptions were also significantly higher among the girls with a CSA experience registration than for the controls. The results highlight the need to systematically evaluate and develop assessment, treatment planning, and interventions offered to adolescent girls after their first CSA experience registration.
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| 7. |
- Vallières, Simon, et al.
(författare)
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Enhanced laser-driven proton acceleration using nanowire targets
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Laser-driven proton acceleration is a growing field of interest in the high-power laser community. One of the big challenges related to the most routinely used laser-driven ion acceleration mechanism, Target-Normal Sheath Acceleration (TNSA), is to enhance the laser-to-proton energy transfer such as to maximize the proton kinetic energy and number. A way to achieve this is using nanostructured target surfaces in the laser-matter interaction. In this paper, we show that nanowire structures can increase the maximum proton energy by a factor of two, triple the proton temperature and boost the proton numbers, in a campaign performed on the ultra-high contrast 10 TW laser at the Lund Laser Center (LLC). The optimal nanowire length, generating maximum proton energies around 6 MeV, is around 1–2 μm. This nanowire length is sufficient to form well-defined highly-absorptive NW forests and short enough to minimize the energy loss of hot electrons going through the target bulk. Results are further supported by Particle-In-Cell simulations. Systematically analyzing nanowire length, diameter and gap size, we examine the underlying physical mechanisms that are provoking the enhancement of the longitudinal accelerating electric field. The parameter scan analysis shows that optimizing the spatial gap between the nanowires leads to larger enhancement than by the nanowire diameter and length, through increased electron heating.
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