Radiation Carrier Research Articles

Room temperature reactions involving silicon dangling bond centers and molecular hydrogen in amorphous SiO2 thin films on silicon

Exposing thin films of amorphous SiO2 to molecular hydrogen at room temperature converts some silicon dangling bond defects, E′ centers, into two hydrogen coupled complexes. These reactions may play important roles in radiation and hot carrier instabilities in metal/oxide/silicon devices.

Room temperature reactions involving silicon dangling bond centers and molecular hydrogen in amorphous SiO/sub 2/ thin films on silicon

Exposing thin films of amorphous SiO/sub 2/ to molecular hydrogen at room temperature converts some silicon dangling bond defects, E' centers, into two hydrogen coupled complexes. It is argued that these reactions may play important roles in radiation and hot carrier instabilities in metal/oxide/silicon devices. The results suggest that an extension of the recent model of M.R. Shaneyfelt et al. (1990) to include molecular hydrogen/E' reactions may provide the most reasonable current explanation for the generation of interface traps at the Si/SiO/sub 2/ boundary. This extension of the Shaneyfelt model would link the idea of molecular hydrogen/oxide defect reactions proposed by D.L. Griscom (1985) with original proton drift ideas of F.B. McLean (1980) and the Shaneyfelt et al. contribution that the proton liberation process is initiated at oxide hole trap sites. >

Silicone nasal radiation carriers

A technique for fabrication of a flexible shielded afterloaded silicone nasal radiation carrier is described. The technique uses a rubber base impression of the nasal cavity from which a silicone radiation carrier is made. Plastic tubes for afterloading of the radioactive sources and a lead shield were incorporated into the carrier. The carrier permitted accurate location of the radioactive sources in the nasal cavity and reduced the radiation exposure.

Influence of electron heating on the dynamic behaviour of semiconductor injection lasers

Electron heating in injection heterostructure lasers can influence high-frequency modulation characteristics and the radiation intensity and carrier density relaxation oscillations. The contributions of different electron heating processes to modulation characteristics have been considered. It is shown that the most important of these processes are stimulated emission heating, free-carrier absorption heating and carrier injection heating. When the impact of the carrier injection process on electron heating is taken into account, it results in considerable broadening of the modulation bandwidth and additional bandwidth broadening takes place when the influence of the photon field within the laser cavity on electron heating is enhanced. Sufficiently far above the laser threshold there is a qualitative change in the dependence of the relaxation oscillation frequency on the bias optical power. This includes a transition from one square root dependence to another square root multiplied by a larger factor as well as a considerable enhancement of the logarithmic decrement.

Speakerphone with wireless infrared microphone

A speakerphone instrument is disclosed having a remote microphone unit providing infrared radiation carrier transmission of voice to a base station coupled to a telephone line. Voice controlled switching of the infrared carrier may be utilized to reduce power consumption. A local microphone in the base station is operable during periods when the remote microphone unit is not transmitting or if the signal-to-noise ratio of the infrared carrier becomes unsatisfactory for voice communication, to pick-up ambient sound and make available a microphone signal for transmission over the telephone line.

Nasopharyngeal impression technique for fabrication of a radiation carrier

A new technique for intracavitary application of Iridium 192 seeds in carcinoma of the nasopharynx is described. This technique allows for accurate construction of a nasopharyngeal carrier that permits the radiotherapist to deliver an adequate dose of irradiation to the nasopharynx.

Afterloaded radiation carrier for carcinoma of the palate. A clinical report

Although every brachytherapy procedure is individualized, similar factors must be considered for each patient. Dental prostheses with modification may be useful in brachytherapy for managing selected patients with malignancies of the oral cavity. The prosthesis described in this article allowed an irregular surface to be treated with a relatively uniform radiation dose, while minimizing radiation exposure to uninvolved tissues and medical personnel. Whereas uniformity of dose is usually desirable in brachytherapy, it assumed even greater importance for this patient because of previous RT.

Radiation carrier for treatment of nasopharyngeal carcinomas

A technique for intracavitary radiation therapy of nasopharyngeal carcinomas has been presented. This technique includes a direct impression technique of the nasopharynx and fabrication of a silicone carrier to house the radioactive source.

Use of the afterloading technique for intraoral radiation carriers

A method for fabrication of a radiation carrier with an adaptation of the afterloading technique has been described. The use of the afterloading technique allows for quick and easy placement of multiple radioactive sources; thus time and exposure to the radiotherapist and the patient are minimized during the period of placement and activation of the prosthesis at the time of therapy.

An intraoral-extraoral radiation carrier for tumors of the lip

The alternatives for treatment of lip tumors have been discussed. The fabrication and use of an intraoralextraoral radiation carrier for iridium 192 have been described.

Use of a complete denture as a radiation carrier.

When surgical resection of intraoral neoplasms is contraindicated, treatment by surface mold irradiation may be used. Success or failure of this mode of treatment may depend on the fabrication of a surface mold that can deliver the prescribed amount of therapeutic radiation in the desired amount of time. A technique for modification of an existing complete denture prosthesis for use as a surface mold has been described. Patient cooperation is essential for successful use of this modified prosthesis.

Lumped-Model Analysis of Microcircuit Vulnerability

Ionizing radiation effects in simple monolithic microcircuits have been predicted from the microcircuit geometry, electrical measurements, and basic semiconductor parameters. Using the lumped-model technique, the mathematical model of the microcircuit is derived directly from the electronic characteristics and boundary values of each bulk semiconductor region. Basic parameter values of the circuit model are obtained by correlating calculated results to the experimental data. Ionizing radiation effects are included as the radiation carrier generation per unit volume. Since the ionizing radiation effect is included in terms of the bulk semiconductor parameters, the radiation-inclusive lumped model is a straightforward extension of the electrical model. Results are presented for (a) the large-signal electrical and radiation-induced response of junction-isolated and dielectric-isolated DTL gates and (b) the small-signal electrical and radiation-induced response of a junction-isolated differential amplifier. Calculation of the electrical and radiation-induced responses was enabled with the use of SCEPTRE1 and ECAP2 circuit analysis computer codes, for the gate and amplifier analyses, respectively. Use of lumped models in the classical circuit element computer codes was accomplished by deriving the analogous R-C-I networks corresponding to the lumped-models. Representation of the electrical performance and radiation-induced response of the microcircuits was generally very good. The major source of error in the analysis is in the representation of the diffused resistor photoresponse, which in this case, did not include the effects of interleg coupling and conductivity modulation.