Search results for "Fysiikka"
showing 10 items of 1348 documents
Upgrade of ALICE forward detectors
2019
ALICE will upgrade its subsystems in 2019−2020 to fully benefit from the increased collision rate and luminosity of the LHC at CERN. Two new forward detectors will be installed at the core of ALICE: the Fast Interaction Trigger (FIT) and the Muon Forward Tracker (MFT). Additionally, during the shutdown between Run 3 and Run 4, there will be an opportunity to install the Forward Calorimeter (FoCal). This paper describes these new forward detectors, their physics justification and goals, selected design features along with performance of detector prototypes and simulated performance figures. peerReviewed
RAPTOR : A new collinear laser ionization spectroscopy and laser-radiofrequency double-resonance experiment at the IGISOL facility
2023
RAPTOR, Resonance ionization spectroscopy And Purification Traps for Optimized spectRoscopy, is a new collinear resonance ionization spectroscopy device constructed at the Ion Guide Isotope Separator On-Line (IGISOL) facility at the University of Jyv\"askyl\"a, Finland. By operating at beam energies of under 10 keV, the footprint of the experiment is reduced compared to more traditional collinear laser spectroscopy beamlines. In addition, RAPTOR is coupled to the JYFLTRAP Penning trap mass spectrometer, opening a window to laser-assisted nuclear-state selective purification, serving not only the mass measurement program, but also supporting post-trap decay spectroscopy experiments. Finally,…
Resonance laser ionization developments for IGISOL-4
2012
The work presented in this thesis concentrates on the development of the FURIOS laser ion source towards e cient and selective production of low energy radioactive ion beams. This includes design and development of the ion guide and hot cavity catcher systems for laser ion source use, and the development of in-source and in-jet laser spectroscopy techniques. The work has been carried out at the IGISOL facility in the Accelerator laboratory of the University of Jyväskylä. The FURIOS facility was upgraded and developed during the move to the IGISOL-4 facility. The laser transport was greatly improved in order to allow a large fraction of the initial laser intensity to be transported into the …
Accessing the gluonic structure of light nuclei at a future electron-ion collider
2020
We show how exclusive vector meson production off light ions can be used to probe the spatial distribution of small-$x$ gluons in the deuteron and $^3$He wave functions. In particular, we demonstrate how short range repulsive nucleon-nucleon interactions affect the predicted coherent $J/\Psi$ production spectra. Fluctuations of the nucleon substructure are shown to have a significant effect on the incoherent cross section above $|t|\gtrsim 0.2\,\mathrm{GeV}^2$. By explicitly performing the JIMWLK evolution, we predict the $x$-dependence of coherent and incoherent cross sections in the EIC energy range. Besides the increase of the average size of the nucleus with decreasing $x$, both the gro…
Being Itself and the Being of Beings : Reading Aristotle’s Critique of Parmenides (Physics 1.3) after Metaphysics
2018
The essay studies Aristotle’s critique of Parmenides (Physics 1.3) in the light of the Heideggerian account of Platonic-Aristotelian metaphysics as an approach to being (Sein) in terms of beings (das Seiende). Aristotle’s critique focuses on the presuppositions of the Parmenidean thesis of the unity of being. It is argued that a close study of the presuppositions of Aristotle’s own critique reveals an important difference between the Aristotelian metaphysical framework and the Parmenidean “protometaphysical” approach. The Parmenides fragments indicate being as such in the sense of the pure, undifferentiated “is there” (τὸ ἐόν)—as the intelligible accessibility of meaningful reality to think…
MARA-separaattorin tyhjiöjärjestelmä
2012
Corrigendum to “Transition from ideal to viscous Mach cones in a kinetic transport approach”
2014
Neutriinojen sekoitusmatriisin Majorana-vaiheet
2013
Lukuisat hiukkasfysiikan kokeet ovat vahvistaneet neutriinojen olevan massallisia hiukkasia ja kykenevän muuttumaan neutriinotyypistä toiseen. Tätä niin kutsuttua neutriino-oskillaatiota parametrisoi neutriinojen sekoitusmatriisi, jota puolestaan parametrisoi kolmen sekoituskulman lisäksi yksi tai kolme CP-symmetriaa rikkovaa vaihetta riippuen siitä ovatko neutriinot Dirac- tai Majorana-hiukkasia. Tässä työssä tarkasteltiin edellä mainittujen Dirac- ja Majorana-vaiheiden merkitystä neutriino-oskillaatioissa, neutriinonottomassa kaksoisbeetahajoamisessa, Higgsin triplettimallissa ja baryoniepäsymmetrian synnyttäneessä leptonigeneesissä. Neutriino-oskillaation tarkastelua varten johdettiin ne…
Differences in the Physical Activity, Sedentary Time, and BMI of Finnish Grade 5 Students
2018
Background: This study examined the distribution of objectively measured physical activity (PA) and sedentary time of fifth-grade students during school, leisure time, and physical education (PE) classes. Demographic, anthropometric, and PA data were collected from 17 representative Finnish schools. Methods: To estimate the PA and sedentary time, participants (N = 592) wore wGT3X-BT ActiGraphs for 7 consecutive days. Comparisons were made between genders and different BMI groups. Results: From the study sample, 43.7% met the moderate to vigorous PA (MVPA) guidelines. Participants spent 62.2% of the day sedentary and 8.2% in moderate and vigorous activities. Boys performed more MVPA than gir…
Production of hydrogen negative ions in an ECR volume source: balance between vibrational excitation and ionization
2018
International audience; The operation of an ECR-driven (2.45 GHz) hydrogen negative ion source is studied. Electron densities and temperatures are investigated with electrostatic probes and negative ion densities are measured with laser photodetachment. Vacuum ultraviolet irradiance measurements are focused on molecular transitions to the ground state while high-resolution visible emission spectroscopy is used to study the transitions between excited states for both molecules and atoms. The standalone operation of the source is found to be more efficient in higher pressures (12 mTorr) where negative ion densities are as high as 4×109 cm−3. Further investigation on the operation of the sou…