Journal of X-Ray Science and Technology - Volume 7, issue 3-4

Authors: Giakos, G.C. | Pillai, B. | Chowdhury, S. | Vedantham, S. | Dasgupta, A. | Kollipara, S. | Passalaqua, A. | Endorf, R. J.

Article Type: Research Article

Abstract: Radiographic studies with the aim of optimizing the imaging potential of Cd1-x Znx Te detectors for digital chest radiography have been performed. A geometrical chest phantom has been designed, and the dependence of both the signal-to-noise ratio and contrast resolution of a planar Cd1-x Znx Te detector on the phantom thickness has been experimentally determined. Specifically, the detected signal and noise contributions were measured and related to phantom thickness. The results of …this study indicate that Cd1-x Znx Te detectors exhibit both high signal-to-noise ratio and contrast resolution. At present time, several studies are in process to experimentally identify and quantify the imaging potential of Cd1-x Znx Te detectors for digital radiographic applications. Show more

Citation: Journal of X-Ray Science and Technology, vol. 7, no. 3-4, pp. 305-315, 1997

Authors: Giakos, G. C. | Pillai, B. | Chowdhury, S. | Vedantham, S. | Dasgupta, A. | Sheffer, D.B. | Davros, W. J. | Passalaqua, A. | Endorf, R. J.

Article Type: Research Article

Abstract: Experiments have been performed with the aim of optimizing the image quality parameters of CdZnTe detectors for digital mammography. A geometrical breast phantom has been designed, and the dependence of the contrast resolution of a planar CdZnTe detector on the phantom thickness has been experimentally determined. Specifically, the detected signal and noise contributions were measured and related to phantom thickness. The results of this study indicate that the CdZnTe detectors exhibit a high contrast resolution. On …the other hand, the dynamic range of this detector can be improved significantly by further implementation of the data acquisition electronics. Show more

Citation: Journal of X-Ray Science and Technology, vol. 7, no. 3-4, pp. 317-326, 1997

Authors: Linlor, William

Article Type: Research Article

Abstract: A new action constant for bremsstrahlung has been derived and published by the author. This paper provides experimental confirmation of that action constant by measurements of the intensity of bremsstrahlung from pure metal elements. Such measurements must be taken under the condition that essentially all of the kinetic energy of an incident electron is converted into the energy of an emergent photon. The dependence of the intensity on the exponent of the atomic number, Z, of …the target element (measured to be 4/3) shows that the new constant is valid. Show more

Citation: Journal of X-Ray Science and Technology, vol. 7, no. 3-4, pp. 327-330, 1997

Authors: Goel, S. K. | Shanker, R.

Article Type: Research Article

Abstract: The first experimental data are presented for the absolute doubly differential cross section (DDCS) for non-characteristics (bremsstrahlung) X-ray spectra produced by 7.0 keV electron bombardment of (semi-thick) targets of silver and gold at a photon detection angle of 90 degree. The bremsstrahlung spectra are corrected for detector's efficiency as well as for target effects; namely, electron energy loss, backscattering and photon-attenuation in the target. The DDCS values so obtained are compared with the predictions of a …thin target bremsstrahlung theory. The agreement between experiment and theory for DDCS both in magnitude and shape is found to be satisfactory within the systematic experimental uncertainty of about 27%. penetrating electrons into the thick targets and the depth distribution of photons generated inside the targets are expected to be also present in the interaction. However, the contributions of these effects to the DDCS have not been taken into consideration. Various possible reasons for the existing discrepancy between experiment and theory are pointed out. Show more

Citation: Journal of X-Ray Science and Technology, vol. 7, no. 3-4, pp. 331-337, 1997

Authors: Ivanova, E. P. | Knight, L. V.

Article Type: Research Article

Abstract: A Ne-like laser scheme is considered for a pure silver plasma. Level populations and gain coefficients are calculated with an atomic-kinetics model. It is shown that large gain values (GL>100) are achievable in a hot dense quasi-steady-state silver plasma at λ=10.038 nm (2-1 transition) and λ=12.298 nm (0-1 transition). Lasing is also possible at λ=2.75 nm (2s-2p transition). The plasma conditions needed are: electron temperature 35& keV and density 5 × 1022 < ne …< 1023 ;cm-3 ;. These plasma conditions can be created with a high-contrast, high-intensity short-pulse visible light laser driver. Show more

Citation: Journal of X-Ray Science and Technology, vol. 7, no. 3-4, pp. 339-347, 1997