Search results for " Lina"
showing 10 items of 26 documents
Nuovi gel di Fricke ad alta sensibilità e bassa diffusione per dosimetria 3D tramite MRI
2017
One of the most recent and promising developments in radiotherapy dosimetry was the introduction of 3D radiationsensitive gels. These gels present tissue equivalent composition and density, so they also serve as phantoms, and their response is largely independent of radiation quality and dose rate. Some gels are infused with ferrous sulfate and rely on the radiation-induced oxidation of ferrous ions to ferric ions (Fricke-gel). In this work Fricke gel dosimeters produced with a matrix of poly-vinyl alcohol (PVA) cross-linked with glutaraldehyde (GTA) were analyzed with magnetic resonance imaging (MRI). This work focused on the analysis of the temporal diffusion of ferric ions through PVA-GT…
Zvaigžņotā Debess: 2000, Pavasaris (167)
2000
Contents: P.Müürsepp. B.Schmidt, Prominent Optician of 20th Century ; J.Miezis. Buildings on the Moon ; Z.Alksne, A.Alksnis. Stars Enshrouded in Envelopes ; A.Alksnis. Goals and Progress of the DENIS Program ; Z.Alksne. Shapley Supercluster – Playground of Clusters of Galaxies ; A.Alksnis. Wide Field Imager Discovers Distant Galaxies ; J.Jaunbergs. Roton SSTO: First Flight Tests ; M.Gills. Space Research 40 Years Ago – Chronicle ; I.Vilks. The Secret of Low-Probability Complexity in the Universe ; K.Bērziņš. On Friendly Terms with Cosmology: Development of Cosmological Views (concluded) ; A.Balklavs. Astronomy in the Internet (WWW) ; V.Flerov, A.Cēbers. Latvia 23rd Open Olympiad of Physics:…
Experimental investigations of the hypernucleus $_Λ^4$H
2015
International audience; Negatively charged pions from two-body decays of stopped _Lambda^4H hypernuclei were studied in 2012 at the Mainz Microtron MAMI, Germany. The momenta of the decay-pions were measured with unprecedented precision by using high-resolution magnetic spectrometers. A challenge of the experiment was the tagging of kaons from associated K^+∧ production off a Be target at very forward angles. In the year 2014, this experiment was continued with a better control of the systematic uncertainties, with better suppression of coincident and random background, improved particle identification, and with higher luminosities. Another key point of the progress was the improvemen…
Sensibilità e stabilità dei dosimetri gel di tipo Fricke esposti ai fotoni nel range clinico in funzione della concentrazione di ferro: 3D MRI ed app…
2014
IRIDE: Interdisciplinary research infrastructure based on dual electron linacs and lasers
2014
This paper describes the scientific aims and potentials as well as the preliminary technical design of RUDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, technological and industrial applications. IRIDE will be a high intensity "particles factory", based on a combination of high duty cycle radio-frequency superconducting electron linacs and of high energy lasers. Conceived to provide unique research possibilities for particle physics, for condensed matter physics, chemistry and material science, for structural biology and industrial applications, IRIDE will open completely new research possibilities and advance our knowledge in many branches of sci…
Design, construction and performance of the energy compressing system of the Mainz 300 MeV electron linac
1973
Abstract For the sake of better energy resolution of the 300 MeV electron linac of Mainz university a system has been built which transforms a sharply bunched beam of poor energy resolution into a beam of sharply defined energy, while its bunches are smeared out. The system is described, its design philosophy and some essential construction details are given. The operating experience of the last 6 months since completion of the system is communicated.
Measurement of the parity violating asymmetry in the quasielastic electron-deuteron scattering and improved determination of the magnetic strange for…
2016
A new measurement of the parity-violating asymmetry in the electron-deuteron quasielastic scattering for backward angles at $⟨{Q}^{2}⟩=0.224\text{ }\text{ }{(\mathrm{GeV}/c)}^{2}$, obtained in the A4 experiment at the Mainz Microtron accelerator (MAMI) facility, is presented. The measured asymmetry is ${A}_{PV}^{d}=(\ensuremath{-}20.11\ifmmode\pm\else\textpm\fi{}0.8{7}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}1.0{3}_{\mathrm{sys}})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$. A combination of these data with the proton measurements of the parity-violating asymmetry in the A4 experiment yields a value for the effective isovector axial-vector form facto…
Tuhoisa influentsa tarttui leskipastorska Pihlin kotikirjastoon: pandemian vaikutus 1800-luvun perheen kirjakokoelmaan
2023
1800-luvulla kirjoilla oli esineinä vielä rahallista ja yhteiskunnalliseen statukseen liittyvää arvoa, ja omistajan kuolema aloitti yleensä vain uuden luvun kirjan elämässä. Tutkin kuolinpesien kirjakokoelmien kohtaloja käyttämällä esimerkkinä erästä 1800-luvun lopun tapausta, jossa leskipastorska Pihl antoi kotikirjastonsa kirjoja helsinkiläiselle Minerva-antikvariaatille myytäväksi. Mikrohistoriallinen esimerkki kertoo perheenjäsenen kuolemantapauksen vaikutuksesta eri sukupuolten ja sukupolvien kirjanomistukseen. Tarkastelen, miten säätyläisperheissä, kuten pappisperheissä, yhtäkkinen kuolema muutti kirjojen omistussuhteita, ja kuinka perheen sisällä miesten ja naisten suhtautuminen kirj…
Characterization of phenolic pellets for ESR dosimetry in photon beam radiotherapy.
2017
We report a study of the dosimetric features of phenolic compounds for applications in radiation therapy dosimetry of clinical photon beams by using ESR spectroscopy. After the optimization of the ESR readout parameters, basic dosimetric properties (such as intra-batch reproducibility, dose-response, sensitivity, linearity, dose rate dependence, tissue-equivalence and signal stability) of laboratory-made phenolic dosimeters in form of pellets were investigated. Furthermore, these dosimeters were tested for measuring the depth dose profile of a 6 MV clinical photon beam. The results reported show that these dosimeters are promising materials for ESR dosimetric applications in radiation thera…
Analysis of response of PVA-GTA Fricke gel dosimeters through magnetic resonance imaging.
2017
The experimental activities here reported are focused on the analysis of the clinical applications of Fricke gel dosimeters produced with a matrix of Polyvinyl alcohol (PVA) cross-linked by adding glutaraldehyde (GTA). The analyses were performed by means of a 1.5 T clinical magnetic resonance imaging (MRI) scanner. The sensitivity of these dosimetric gels to clinical photon beams as well as the signal stability were suitably investigated. Furthermore, the effect of the xylenol orange on the MRI signal was analyzed. The results obtained show that these PVA-GTA gel dosimeters show good dosimetric features for possible future use for 3D dose mapping in clinical applications.