| 1. |
- Aamodt, K., et al.
(författare)
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The ALICE experiment at the CERN LHC
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
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Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
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| 2. |
- Ballan, M., et al.
(författare)
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Nuclear physics midterm plan at Legnaro National Laboratories (LNL)
- 2023
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Ingår i: European Physical Journal Plus. - 2190-5444. ; 138:8, s. 3-26
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Tidskriftsartikel (refereegranskat)abstract
- The next years will see the completion of the radioactive ion beam facility SPES (Selective Production of Exotic Species) and the upgrade of the accelerators complex at Istituto Nazionale di Fisica Nucleare – Legnaro National Laboratories (LNL) opening up new possibilities in the fields of nuclear structure, nuclear dynamics, nuclear astrophysics, and applications. The nuclear physics community has organised a workshop to discuss the new physics opportunities that will be possible in the near future by employing state-of-the-art detection systems. A detailed discussion of the outcome from the workshop is presented in this report.
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| 3. |
- Kilpeläinen, Tuomas O, et al.
(författare)
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Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.
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| 4. |
- Dabrowski, A. E., et al.
(författare)
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Measuring the bunch frequency multiplication at CTF3
- 2010
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Konferensbidrag (refereegranskat)abstract
- The CTF3 facility is being built and commissioned by an international collaboration in order to test the feasibility of the proposed CLIC drive beam generation scheme. Central to this scheme is the use of RF deflectors to inject bunches into a Delay Loop and a Combiner Ring, in order to transform the initial bunch spacing of 1.5 GHz from the linac to a final bunch spacing of 12 GHz. The optimization procedure relies on several steps. The active length of each ring is carefully adjusted to within a few millimeters accuracy using a two‐period undulator. The transverse optics of the machine must be set-up in a way so as to ensure the beam isochronicity. Diagnostics based on optical streak cameras and RF power measurements have been designed to measure the longitudinal behaviour of the beam during the combination. This paper presents their performance and highlights recent measurements.
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| 5. |
- Dabrowski, A. E., et al.
(författare)
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Measuring the bunch frequency multiplication at the 3rd CLIC Test Facility
- 2012
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 7, s. P01005-
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Tidskriftsartikel (refereegranskat)abstract
- The CLIC Test Facility 3 (CTF3) is being built and commissioned by an international collaboration to test the feasibility of the proposed Compact Linear Collider (CLIC) drive beam generation scheme. Central to this scheme is the use of RF deflectors to inject bunches into a delay loop and a combiner ring, in order to transform the initial bunch frequency of 1.5 GHz from the linac to a final bunch frequency of 12 GHz. To do so, the machine's transverse optics must be tuned to ensure beam isochronicity and each ring's length can finally be adjusted with wiggler magnets to a sub millimeter path length accuracy. Diagnostics based on optical streak camera and RF power measurements, in particular frequency bands, have been designed to measure the longitudinal behaviour of the beam during the combination. This paper presents the diagnostics and recent commissioning measurements.
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| 6. |
- Constance, B., et al.
(författare)
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Experimental Verification of the CLIC Two-Beam Acceleration Technology in CTF3
- 2013
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Ingår i: IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference. - 9783954501229 ; , s. 1436-1438
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Konferensbidrag (refereegranskat)abstract
- The Compact Linear Collider international collaboration is pursuing an extensive R&D program towards a multi- TeV electron-positron collider. In particular, the development of two-beam acceleration technology is the focus of the CLIC test facility CTF3. In this paper we summarise the most recent results obtained at CTF3: The results of the studies on the drive beam generation are presented, the achieved two beam acceleration performance is reported and the measured breakdown rates and related observations are summarised. The stability of the deceleration process performed over 12 subsequent modules and a comparison of the obtained results with the theoretical expectations are discussed. We also outline the future experimental program.
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| 7. |
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| 8. |
- Dubrovskiy, A., et al.
(författare)
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Review of the drive beam stabilization in the CLIC test facility CTF3
- 2013
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Ingår i: IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference. - 9783954501229 ; , s. 2666-2668
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Konferensbidrag (refereegranskat)abstract
- CTF3 is a Test Facility focusing on beam-based studies of the key concepts of the Compact Linear Collider CLIC. Over the past several years many aspects of the CLIC two-beam acceleration scheme were studied in CTF3, including the crucial issue of drive beam stability. The main sources of drifts and instabilities have been identified and mitigated, helping to improve the machine performance and showing significant progress towards the experimental demonstration of the very stringent requirements on current, energy and phase stability needed in CLIC. In this paper, the more effective techniques and feed-backs are summarized. The latest measurements on beam stability are reported and their relevance to CLIC is discussed.
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| 9. |
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| 10. |
- McCarthy, Randy J., et al.
(författare)
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Registered Replication Report on Srull and Wyer (1979)
- 2018
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Ingår i: Advances in Methods and Practices in Psychological Science. - : SAGE Publications Inc. - 2515-2459 .- 2515-2467. ; 1:3, s. 321-336
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Tidskriftsartikel (refereegranskat)abstract
- Srull and Wyer (1979) demonstrated that exposing participants to more hostility-related stimuli caused them subsequently to interpret ambiguous behaviors as more hostile. In their Experiment 1, participants descrambled sets of words to form sentences. In one condition, 80% of the descrambled sentences described hostile behaviors, and in another condition, 20% described hostile behaviors. Following the descrambling task, all participants read a vignette about a man named Donald who behaved in an ambiguously hostile manner and then rated him on a set of personality traits. Next, participants rated the hostility of various ambiguously hostile behaviors (all ratings on scales from 0 to 10). Participants who descrambled mostly hostile sentences rated Donald and the ambiguous behaviors as approximately 3 scale points more hostile than did those who descrambled mostly neutral sentences. This Registered Replication Report describes the results of 26 independent replications (N = 7,373 in the total sample; k = 22 labs and N = 5,610 in the primary analyses) of Srull and Wyer?s Experiment 1, each of which followed a preregistered and vetted protocol. A random-effects meta-analysis showed that the protagonist was seen as 0.08 scale points more hostile when participants were primed with 80% hostile sentences than when they were primed with 20% hostile sentences (95% confidence interval, CI = [0.004, 0.16]). The ambiguously hostile behaviors were seen as 0.08 points less hostile when participants were primed with 80% hostile sentences than when they were primed with 20% hostile sentences (95% CI = [?0.18, 0.01]). Although the confidence interval for one outcome excluded zero and the observed effect was in the predicted direction, these results suggest that the currently used methods do not produce an assimilative priming effect that is practically and routinely detectable.
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| 11. |
- Olvegård, Maja, et al.
(författare)
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High intensity profile monitor for time resolved spectrometry at the CLIC Test Facility 3
- 2012
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 683, s. 29-39
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Tidskriftsartikel (refereegranskat)abstract
- The power source of the Compact Linear Collider (CLIC) relies on the generation and deceleration of a high-intensity electron drive beam. In order to provide the best radio-frequency (RF) to beam-energy transfer efficiency, the electron beam is accelerated using fully loaded RF cavities, which leads to strong beam loading effects resulting in a high-energy transient. The stability of the RF power produced by the drive beam depends on the stability of the drive beam energy and energy spread along the pulse. The control and the monitoring of the time evolution of the beam energy distribution are therefore crucial for the accelerator performance. For this purpose segmented beam dumps, which are simple and robust devices, have been designed and installed at the CLIC Test Facility 3 (CTF3). These devices are located at the end of spectrometer lines and provide horizontal beam profiles with a time resolution better than 10 ns. The segmented dumps are composed of parallel, vertical, metallic plates, and are based on the same principle as a Faraday cup: the impinging beam current is read by a fast acquisition channel. Both FLUKA and Geant4 simulations were performed to define the optimum detector geometry for beam energies ranging from 5 MeV to 150 MeV. This paper presents a detailed description of the different steps of the design: the optimization of the detector spatial resolution, the minimization of the thermal load and the long-term damage resulting from high radiation doses. Four segmented dumps are currently used in the CTF3 complex. Their measured performance and limitations are presented in this paper. Typical beam spectra as measured in the CTF3 linac are also presented along with a description of the RF manipulations needed for tuning the beam energy spectrum.
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| 12. |
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| 13. |
- Persson, Tobias, 1985, et al.
(författare)
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Beam Stability at CTF3
- 2012
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Ingår i: IPAC 2012 - International Particle Accelerator Conference 2012. - 9783954501151 ; , s. 1888-1890
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Konferensbidrag (refereegranskat)abstract
- The two-beam acceleration tested at CTF3 imposes verytight tolerances on the drive beam stability. A descriptionof the specialized monitoring tool developed to identify thedrifts and jitter in the machine is presented. It compares all the relevant signals in an on-line manner to help the operator to identify drifts and to log data for off-line analysis. The main sources for the drifts of the drive beam have been identified and their causes are described. A feedback applied to the RF was implemented to reduce the effects. It works by changing the waveform for the pulse compression to compensate for the drifts.
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| 14. |
- Persson, Tobias, 1985, et al.
(författare)
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Drive beam stability studies and stabilization algorithms in CLIC Test Facility 3
- 2014
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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. ; 735, s. 152-156
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Tidskriftsartikel (refereegranskat)abstract
- In this paper the study of the mechanisms responsible for the time varying beam current losses in CTF3 (CLIC Test Facility 3), together with the feedbacks implemented to mitigate them, is presented. The study shows that the losses were linked mainly to the energy variation induced by the RF (Radio frequency) amplitude fluctuations. The RF-amplitude instability sources were identified. A feedback developed to mitigate this instability, acting on the RF-compression system by controlling the phase program of the klystron, is described in detail. The result is a significant improvement of the overall stability in the machine. The energy variation is reduced further with the use of an energy feedback operating on the RF-amplitude of the last klystron in the CTF3 linac. This feedback loop closes on the energy measured from a dispersive pickup after the linac. With the energy stabilized a beam current stability close to the CLIC (Compact Linear Collider) specification for a factor 4 combined beam was achieved.
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| 15. |
- Skowroński, P. K., et al.
(författare)
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Optics performance of the LHC during the 2012 run
- 2013
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Ingår i: IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference. - 9783954501229 ; , s. 1433-1435
-
Konferensbidrag (refereegranskat)
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| 16. |
- Tomas, R., et al.
(författare)
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Record low beta beating in the LHC
- 2012
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Ingår i: Physical Review Special Topics. Accelerators and Beams. - 1098-4402. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- The LHC is currently operating with a proton energy of 4 TeVand beta* functions at the ATLAS and CMS interaction points of 0.6 m. This is close to the design value at 7 TeV ( beta* = 0.55 m) and represented a challenge for various aspects of the machine operation. In particular, a huge effort was put into the optics commissioning and an unprecedented peak beta beating of around 7% was achieved in a high energy hadron collider.
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| 17. |
- Verschuere, Bruno, et al.
(författare)
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Registered Replication Report on Mazar, Amir, and Ariely (2008)
- 2018
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Ingår i: Advances in Methods and Practices in Psychological Science. - : SAGE Publications. - 2515-2459 .- 2515-2467. ; 1:3, s. 299-317
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Tidskriftsartikel (refereegranskat)abstract
- The self-concept maintenance theory holds that many people will cheat in order to maximize self-profit, but only to the extent that they can do so while maintaining a positive self-concept. Mazar, Amir, and Ariely (2008, Experiment 1) gave participants an opportunity and incentive to cheat on a problem-solving task. Prior to that task, participants either recalled the Ten Commandments (a moral reminder) or recalled 10 books they had read in high school (a neutral task). Results were consistent with the self-concept maintenance theory. When given the opportunity to cheat, participants given the moral-reminder priming task reported solving 1.45 fewer matrices than did those given a neutral prime (Cohen’s d = 0.48); moral reminders reduced cheating. Mazar et al.’s article is among the most cited in deception research, but their Experiment 1 has not been replicated directly. This Registered Replication Report describes the aggregated result of 25 direct replications (total N = 5,786), all of which followed the same preregistered protocol. In the primary meta-analysis (19 replications, total n = 4,674), participants who were given an opportunity to cheat reported solving 0.11 more matrices if they were given a moral reminder than if they were given a neutral reminder (95% confidence interval = [−0.09, 0.31]). This small effect was numerically in the opposite direction of the effect observed in the original study (Cohen’s d = −0.04).
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