Search results for "fluorescence"
showing 10 items of 2463 documents
A multi-analytical non-invasive and micro-invasive approach to canvas oil paintings. General considerations from a specific case
2017
Abstract The investigation of artwork to understand story, state of conservation and to know about the composing materials is an issue that is getting growing attention in specialized literature. From a methodological point of view the scientific community is trying to reach a common proposal that could contribute to define a Standard Operating Procedure (SOP) for the application of portable non-invasive and microinvasive techniques for in-situ analyses. In this paper the oil painting on canvas “St. Girolamo nello studio” by Nicolo Buttafoco was investigated to known the materials and techniques used by the artist as well as to evaluate its preservation status. The survey has been conducted…
Ion-induced fluorescence imaging of endosomes
2013
Abstract Imaging laboratories at Jyvaskyla and Singapore are collaborating on the development of fluorescence imaging of cytoplasmic endosomes using a combination of proton induced fluorescence (PIF) with direct Scanning Transmission Ion Microscopy (direct-STIM) for sub-cellular structural imaging. A549 lung carcinoma cells were cultivated and stained for epidermal growth factor receptor (EGFR) and receptor α2β1 integrin. In this paper, we demonstrate that cells can be imaged at sub-150 nm resolution using the PIF technique. In addition, the same target cell was imaged at 50 and 25 nm resolution by using proton and He-STIM, respectively. The combination of both techniques offer a powerful t…
Multilayered samples reconstructed by measuring Kα/Kβ or Lα/Lβ X-ray intensity ratios by EDXRF
2013
Abstract In this paper a general method based on energy-dispersive X-ray fluorescence (EDXRF) analysis has been tested to assess its possible use as a tool to reconstruct the structure and determine the thickness of two and/or multi-layered materials. The method utilizes the X-ray intensity ratios of Kα/Kβ or Lα/Lβ peaks (or the ratio of these peaks) for selected elements present in multi-layered objects of various materials (Au alloys, gilded Cu, gilded Ag, gilded Pb, Ag–Au Tumbaga, stone surfaces with protective treatments, Zn or Nickel plating on metals). Results show that, in the case of multi-layered samples, a correct calculation of the peak ratio (Kα /Kβ and/or Lα/Lβ) of relevant ele…
First collinear laser spectroscopy measurements of radioisotopes from an IGISOL ion source
1997
Abstract The standard Doppler-free technique of collinear laser spectroscopy has been successfully applied to radioisotopes from the ion-guide isotope separator (IGISOL) at the University of Jyvaskyla. The laser resonance fluorescence signals for the 140,142,144 Ba radioisotopes show that the ion beam energy spread is less than 6 eV, allowing the laser technique to have both high resolution and a sensitivity comparable with the best obtained at conventional facilities.
Determination of the isotope shift in theD 1 line between197Au and195Au
1983
The isotope shift between197Au (stable) and195Au (T 1/2=183 d) was determined by resonance fluorescence and polarization spectroscopy in the 6s2 S 1/2 -6p 2 P 1/2, λ =267.6nm line. The result is δν195, 197=-2.9(2) GHz corresponding to a change of the mean-square charge radius by δ〈r 2〉195, 197=0.063(9) fm2. The sample was confined to a resonance cell heated to temperatures of up to 1500°C.
Low temperature X-ray luminescence of KNbO3 crystals
2000
We have studied X-ray luminescence of KNbO3 single crystal. The 575 nm luminescence band has been studied in the temperature range of 15‐45 K. The quenching parameters were found to be Qa 12 3 meV and ma 4 10 11 s ˇ1 .N o luminescence has been observed under heavy ion excitation ( 86 Kr ions, 8.63 MeV/amu) even at 15 K. ” 2000 Elsevier
ESR response of watch glasses to proton beams
2010
In this paper we have analyzed the electron spin resonance (ESR) signal of watch glasses irradiated with %60 MeV proton beams in the dose range between 1 and 105 Gy. The composition of samples expressed in oxides weight percentages has been obtained carrying out X-ray fluorescence spectrometry (XRF) mea- surements. The ESR signal has been studied in terms of its dependence on microwave power and modulation field in order to choose the optimal recording parameters. The dependence of the radioinduced signal on the exposure dose has been investigated. A numerical procedure aimed at improving the sensitivity in the low dose range has been developed.
Spectroscopic factor and proton formation probability for the d3/2 proton emitter 151Lu
2017
The quenching of the experimental spectroscopic factor for proton emission from the short-lived $d_{3/2}$ isomeric state in $^{151m}$Lu was a long-standing problem. In the present work, proton emission from this isomer has been reinvestigated in an experiment at the Accelerator Laboratory of the University of Jyv\"{a}skyl\"{a}. The proton-decay energy and half-life of this isomer were measured to be 1295(5) keV and 15.4(8) $\mu$s, respectively, in agreement with another recent study. These new experimental data can resolve the discrepancy in the spectroscopic factor calculated using the spherical WKB approximation. Using the R-matrix approach it is found that the proton formation probabilit…
Study of the recombination around the excitonic region of MBE ZnSe:Cl thin films
2008
The recombination processes around the excitonic region of undoped ZnSe and chlorine doped ZnSe thin films were studied by continuous-wave photoluminescence (cw-PL) and time-resolved photoluminescence (TRPL) spectroscopies. Samples with different chlorine concentration were obtained by varying the temperature of the Cl source. The evolution of the PL signal and its decay time were analyzed as a function of temperature. Activation energy (Ea) values associated to the quenching of the D0X and band-to-band emission were obtained from the temperature dependent cw-PL experiments. The activation energy was lower for the film with higher Cl content. The characteristic exponential decay time (TPL) …
Magnetic predissociation in Te 2 B 1 u
1997
We report a registration of magnetic predissociation (MPD) of electronically excited molecules via peculiarities in magnetic field B induced alignment-orientation conversion (AOC). Non-linear magnetic energy shift and heterogeneous MPD produce dispersion type fluorescence circularity signals C(B) of different sign. Measurements on B 1 u - , v(J) equals 2(96) state of 130 Te 2 yielded natural C v het equals plus or minus 6 s -1/2 and magnetic (alpha) v het equals minus or plus 9 multiplied by 10 3 s -1/2 T -1 rate constants of heterogeneous PD, supposing that the B1 u - state PD takes place through O u - state continuum.