S. Chwirot

Ultraviolet laser-induced fluorescence of human stomach tissues : Detection of cancer tissues by imaging techniques

The background for this work was several literature reports on applications of the fluorescence methods to detection and localization of human cancers. The objective of our study has been to investigate if such an approach could be applied for the detection of gastric cancers.

Electron-photon coincidence study of the collisional excitation of the Ca state

Experimental values of the electron-impact coherence parameters (EICP) are reported for electron-impact excitation of the state of Ca. The results have been obtained using electron-photon coincidence techniques for incident electron energies of 45 and 60 eV and scattering angles of and . EICP values determined at 45 eV are compared with similar data obtained by other groups with coincidence and optical pumping methods. Our data do not show a disagreement with the theoretical calculations based on a relativistic distorted-wave approximation (RDWA) that was reported for earlier experimental coincidence results.

Coincidence study of excitation of cadmium atoms by electron impact

We present experimental values of the electron impact coherence parameters (EICP) and reduced Stokes parameters for excitation of 51P1 state of cadmium atoms. The results have been obtained using electron–photon coincidence technique for incident electron energies 80 eV and 60 eV and electron scattering angles in the range of 5° to 50°. We also present an additional set of data for electron energy 100 eV and scattering angle 50° which complements our previous results. All the experimental values are compared with theoretical relativistic distorted-wave approximation (RDWA) calculations. The first Born approximation (FBA) predictions of the alignment angle are also presented. The theoretical results are in good qualitative agreement with the experimental data.

Magnetic angle changer?a new device allowing extension of electron?photon coincidence measurements to arbitrarily large electron scattering angles

The electron–photon coincidence technique has been used as the most sensitive tool for investigating inelastic collisions of atoms with electrons and heavy particles and led to new insights into collision dynamics theory. However, for purely geometrical reasons, due to finite sizes of the electron energy analysers and electron beam sources, the measurements have not been carried out for the largest scattering angles. We present a novel system for electron–photon coincidence experiments on electron inelastic scattering with the magnetic angle changer allowing determination of excitation parameters at arbitrarily large scattering angles. As shown by experimental tests, our device can be successfully used in the electron–photon coincidence experiment and it has unprecedented efficacy—deflection angle up to 60° for 100 eV electrons, without a ferromagnetic core.

Electron - photon polarization correlation study of the state of Ca atoms excited by electron impact

Measurements are reported for the polarization of the fluorescence arising from the excitation of the state of Ca atoms detected in coincidence with electrons scattered with a suitable energy loss. The excitation parameters have been determined at an electron incidence energy of 100 eV for five scattering angles between and . Calculations for the measured parameters are also performed using the relativistic distorted-wave approximation. The theoretical results are presented and compared with the experimental data.

Coincidence measurements of electron-impact coherence parameters for e-He scattering in the full range of scattering angles

Electron impact coherence parameters for inelastic e-He scattering have been measured for the excitation to the 2 {sup 1}P{sub 1} state at collision energy of 100 eV. The experiment was conducted using angular correlation electron-photon coincidence technique with a magnetic angle changer allowing measurements in full range of scattering angles. The results are compared with other experimental data and theoretical predictions available for this collisional system.

Electron impact ionization of calcium atoms inside quadrupole trap

Loading a Paul trap with ions requires application of ionization process of any type. In the case of calcium ions, two photoionization schemes [1, 2] are commonly used. High-energy (keV) electron impact technique was also used before development of the optical methods. Our experimental results confirmed that the electronic ionization can be relatively easily achieved for energies below 100 eV. The proposed technique provides ion production rate at the level of hundreds of new ions per second. An efficiency of ionization strictly depends on experimental conditions such as energy and density of the electron beam, atomic beam density and trapping potential parameters. Thus, analysis of the cloud of trapped ions for given conditions delivers information about integral cross sections for electron impact ionization processes. The ion production rate is given by equation:

E-Zn inelastic scattering at 80 eV

Stokes and Electron Impact Coherence Parameters (EICPs) for electronic excitation of 41P1 state of zinc atoms have been measured for incident electron energy of 80 eV. The experimental data are presented together with Convergent Close Coupling (CCC) theoretical predictions. Our results are compared with recently published Relativistic Distorted-Wave Approximation (RDWA) calculations.

Endogenous fluorescence - new approach to in situ detection of premalignant and malignant lesions in human organs

Autofluorescence-endogenous fluorescence of cells and tissues has been known for many years. For a long time it has been considered mostly a phenomenon producing unwanted background impairing a quality of fluorescence microscopic images. First reports on a diagnostic potential of the autofluorescence for a detection of premalignant and malignant lesions were published only at the end of 1990. This paper presents basic ideas of such techniques and their applications in the field of tumor detection.

Electron-photon coincidence measurements of polarization of radiation from cadmium atoms excited to 51P1 state by electron impact

The coherence analysis technique has been used to determine the state of polarizatitn of 228.8 nm radiation emitted by cadmium atoms excited to 51P1 state by electron impact. Data have been obtained for incident electron energy of 100 eV for scattering angles in the range from 10° to 40°. Reduced Stokes parameters and electron impact coherence parameters (EICP), characterizing the state of the excited atoms immediately after the collision, have been extracted from the measurements and compared with results of relativistic distorted-wave approximation calculations. Theoretical predictions are in good qualitative agreement with experimental values.