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Hardening of transistor circuits to ionizing radiation

Description: It is shown experimentally that transistor circuits may have their fundamental sensitivities to ionizing radiation reduced by factors of ten by addition of a simple reverse biased diode. Bipolar transistors, field effect transistors and microcircuits have been hardened. (auth)
Date: September 10, 1965
Creator: Crowe, J.W.
Partner: UNT Libraries Government Documents Department

BUSFET - A Novel Radiation-Hardened SOI Transistor

Description: A partially-depleted SOI transistor structure has been designed that does not require the use of specially-processed hardened buried oxides for total-dose hardness and maintains the intrinsic SEU and dose rate hardness advantages of SOI technology.
Date: February 4, 1999
Creator: Dodd, P.E.; Draper, B.L.; Schwank, J.R. & Shaneyfelt, M.R.
Partner: UNT Libraries Government Documents Department

Stability of Trapped Electrons in SiO(2)

Description: Thermally stimulated current and capacitance voltage methods are used to investigate the thermal stability of trapped electrons associated with radiation-induced trapped positive charge in metal-oxide-semiconductor capacitors. The density of deeply trapped electrons in radiation-hardened 45 nm oxides exceeds that of shallow electrons by a factor of {approximately}3 after radiation exposure, and by up to a factor of 10 or more during biased annealing. Shallow electron traps anneal faster than deep traps, and seem to be at least qualitatively consistent with the model of Lelis et al. Deeper traps maybe part of a fundamentally distinct dipole complex, and/or have shifted energy levels that inhibit charge exchange with the Si.
Date: January 29, 1999
Creator: Fleetwood, D.M. & Winokur, P.S.
Partner: UNT Libraries Government Documents Department

Laser conditioning methods fo hafnia silica multiplayer mirrors

Description: Large aperture multilayer hafnia silica high reflector coatings at 1064 nm, deposited by reactive electron-beam deposition, were prepared to examine different laser conditioning methods for manufacturing high fluence optics in the National Ignition Facility. Laser conditioning is a process where the damage threshold of the coating is increased or the damage that is created is minimized so that it does not grow upon further irradiation. Two laser conditioning methods were examined for coatings deposited from only oxide starting materials. Off-line laser conditioning consists of raster scanning a mirror past a 1 mm diameter Gaussian beam over the entire clear aperture; a process that takes approximately 24 hours per scan. On-line laser conditioning consisted of a large aperture 300 mm x 300 mm beam from the Beamlet laser that irradiated the entire full clear aperture of a series of mirrors; a process that was limited by a 2-4 hour shot rate. In both cases a six-step process was used with the mirror first irradiated at a low fluence, then successively higher fluences increased in equal increments up to the peak laser operating fluence. Mirrors that were only partially laser conditioned damaged catastrophically while fully conditioned mirrors survived fluences exceeding the safe operating Beamlet fluence. An alternative off-line laser conditioning method was examined for coatings deposited from hafnia or metallic hafnium sources. Single-step laser conditioning consists of off-line raster scanning an optic at the peak operating fluence, thus decreasing the laser conditioning cost by reducing the number of scans and required laser conditioning stations to process all the mirrors for the National Ignition Facility. Between pulses the optic is stepped approximately one fourth of the l/e* Gaussian beam diameter so each area of the coating is irradiated by different segments of the beam starting at a low fluence at the outer edge ...
Date: January 6, 1998
Creator: Stolz, C.J.; Sheehan, L.M.; Maricle, S.M. Schwartz, S.; Kozlowski, M.R.; Jennings, R.T. & Hue, J.
Partner: UNT Libraries Government Documents Department

Depth-independent hardness improvements in ion irradiated polystyrene

Description: Polystyrene (PS) was irradiated with 2 MeV He{sup +} ions to a fluence of 3.3 {times} 10{sup 9} ions/m{sup 2}. A cross-section of the irradiated layer was subjected to hardness measurements across the section using a nanoindentation technique. Results showed that hardness increased as a function of irradiation depth and showed a maximum value of 12 GPa at a depth of approximately 6.5 {mu}m, for a total ion penetration range of 9 {mu}m, as compared to a hardness of 0.45 GPa for unirradiated PS. The hardness variation with depth followed the trend for Linear Energy Transfer (LET) for ionization from the energetic ions to substrate atoms. This investigation showed for the first time how hardness varies as a function of depth for ion-irradiated polymers; this variation approximately follows the ionization LET profile, suggesting that cross-linking in the polymers could be proportional to ionization.
Date: December 31, 1994
Creator: Rao, G.R.; Riester, L. & Lee, E.H.
Partner: UNT Libraries Government Documents Department

ONLINE MEASUREMENT OF THE PROGRESS OF DECONTAMINATION

Description: In order to determine if the sensor technology and the decontamination technology will face problems once integrated, a feasibility study (see Appendix B) was produced in which the effect of motion on the efficiency of a radiation sensor was measured. It was found that the effect is not negligible; however, it is not catastrophic, and if the sensors are properly calibrated, this obstacle can be overcome. During the first year of this project, many important tasks have been accomplished. The search for radiation sensors provided knowledge on the technologies commercially available. This, in turn, allowed for a proper assessment of the properties, limitations, different methods of measurement, and requirements of a large number of sensors. The best possible characterization and data collection instrument and decontamination technologies were chosen using the requirement information in Appendix A. There are technical problems with installing sensors within the blasting head, such as steel shot and dust interference. Therefore, the sensor array is placed so that it will measure the radioactivity after the blasting. Sensors are rather sensitive, and therefore it is not feasible to place the sensor windows in such an abrasive environment. Other factors, such as the need for radiation hardening in extreme cases, and the possible interference of gamma rays with the radio frequency modem, have been considered. These factors are expected to be negligible and can be revisited at the time of prototype production. Factors that need to be addressed are the vibrations of the blasting unit and how to isolate the sensor array from these. In addition, an electromagnetic survey must be performed to ensure there will be no interference with the electronic component that will be integrated. The integration design is shown in section 4.0.
Date: January 1, 1999
Creator: M.A. Ebadian, Ph.D.
Partner: UNT Libraries Government Documents Department

Radiation tolerant circuits designed in 2 commercial 0.25{micro} CMOS processes

Description: Characterization of simple devices as well as complex circuits, in two commercial 0.25{micro} processes, demonstrates a high level (up to 58 Mrad) radiation tolerance of these technologies. They are also very likely to be immune to single event gate damage according to the results from 200 MeV-protons irradiation.
Date: March 8, 2001
Creator: Mekkaoui, A.
Partner: UNT Libraries Government Documents Department

Challenges in hardening technologies using shallow-trench isolation

Description: Challenges related to radiation hardening CMOS technologies with shallow-trench isolation are explored. Results show that trench hardening can be more difficult than simply replacing the trench isolation oxide with a hardened field oxide.
Date: February 1, 1998
Creator: Shaneyfelt, M.R.; Dodd, P.E.; Draper, B.L. & Flores, R.S.
Partner: UNT Libraries Government Documents Department

High performance static latches with complete single event upset immunity

Description: This invention is comprised of a logical memory latch and cell, using logic and circuit modifications, provides SEU immunity without loss of speed. A single logic state is hardened against SEU using technology methods and the information concerning valid states is then based to simplify hardened circuit design.
Date: December 31, 1991
Creator: Corbett, W.T. & Weaver, H.T.
Partner: UNT Libraries Government Documents Department

FPIX2: A radiation-hard pixel readout chip for BTeV

Description: A radiation-hard pixel readout chip, FPIX2, is being developed at Fermilab for the recently approved BTeV experiment. Although designed for BTeV, this chip should also be appropriate for use by CDF and DZero. A short review of this development effort is presented. Particular attention is given to the circuit redesign which was made necessary by the decision to implement FPIX2 using a standard deep-submicron CMOS process rather than an explicitly radiation-hard CMOS technology, as originally planned. The results of initial tests of prototype 0.25{micro} CMOS devices are presented, as are plans for the balance of the development effort.
Date: December 11, 2000
Creator: al., David C. Christian et
Partner: UNT Libraries Government Documents Department

New Insights into Fully-Depleted SOI Transistor Response During Total-Dose Irradiation

Description: Previous work showed the possible existence of a total-dose latch effect in fully-depleted SOI transistors that could severely limit the radiation hardness of SOI devices. Other work showed that worst-case bias configuration during irradiation was the transmission gate bias configuration. In this work we further explore the effects of total-dose ionizing irradiation on fully-depleted SOI transistors. Closed-geometry and standard transistors fabricated in two fully-depleted processes were irradiated with 10-keV x rays. Our results show no evidence for a total-dose latch effect as proposed by others. Instead, in absence of parasitic trench sidewall leakage, our data suggests that the increase in radiation-induced leakage current is caused by positive charge trapping in the buried oxide inverting the back-channel interface. At moderate levels of trapped charge, the back-channel interface is slightly inverted causing a small leakage current to flow. This leakage current is amplified to considerably higher levels by impact ionization. Because the back-channel interface is in weak inversion, the top-gate bias can modulate the back-channel interface and turn the leakage current off at large, negative voltage levels. At high levels of trapped charge, the back-channel interface is fully inverted and the gate bias has little effect on leakage current. However, it is likely that this current also is amplified by impact ionization. For these transistors, the worst-case bias configuration was determined to be the ''ON'' bias configuration. These results have important implication on hardness assurance.
Date: September 14, 1999
Creator: BURNS,J.A.; DODD,PAUL E.; KEAST,C.L.; SCHWANK,JAMES R.; SHANEYFELT,MARTY R. & WYATT,P.W.
Partner: UNT Libraries Government Documents Department

Use of COTS [commercial-off-the-shelf] Microelectronics in Radiation Environments

Description: This paper addresses key issues for the cost-effective use of COTS microelectronics in radiation environments that enable circuit or system designers to manage risks and ensure mission success. COTS parts with low radiation tolerance should not be used when they degrade mission critical functions or lead to premature system failure. We review several factors and tradeoffs affecting the successful application of COTS parts including (1) hardness assurance and qualification issues, (2) system hardening techniques, and (3) life-cycle costs. The paper also describes several experimental studies that address trends in total-dose, transient, and single-event radiation hardness as COTS technology scales to smaller feature sizes. As an example, the level at which dose-rate upset occurs in Samsung SRAMS increases from 1.4x10{sup 8} rads(Si)/s for a 256K SRAM to 7.7x10{sup 9} rads(Si)/s for a 4M SRAM, indicating unintentional hardening improvements in the design or process of a commercial technology. Additional experiments were performed to quantify variations in radiation hardness for COTS parts. In one study, only small (10-15%) variations were found in the dose-rate upset and latchup thresholds for Samsung 4M SRAMS from three different date codes. In another study, irradiations of 4M SRAMS from Samsung, Hitachi, and Toshiba indicate large differences in total-dose radiation hardness. The paper attempts to carefully define terms and clear up misunderstandings about the definitions of ''COTS'' and ''radiation-hardened'' technology.
Date: July 7, 1999
Creator: Winokur, P.S.; Lum, G.K.; Shaneyfelt, M.R.; Sexton, F.W.; Hash, G.L. & Scott, L.
Partner: UNT Libraries Government Documents Department

Radiation Hardening of CMOS Microelectronics

Description: A unique methodology, silicon transfer to arbitrary substrates, has been developed under this program and is being investigated as a technique for significantly increasing the radiation insensitivity of limited quantities of conventional silicon microelectronic circuits. In this approach, removal of the that part of the silicon substrate not required for circuit operation is carried out, following completion of the circuit fabrication process. This post-processing technique is therefore applicable to state-of-the-art ICs, effectively bypassing the 3-generation technology/performance gap presently separating today's electronics from available radiation-hard electronics. Also, of prime concern are the cost savings that result by eliminating the requirement for costly redesign of commercial circuits for Rad-hard applications. Successful deployment of this technology will result in a major impact on the radiation hard electronics community in circuit functionality, design and software availability and fabrication costs.
Date: February 20, 2000
Creator: McCarthy, A. & Sigmon, T.W.
Partner: UNT Libraries Government Documents Department

Special design problems and solutions for high powered continuous duty linacs

Description: Several high powered linac designs are being considered for various purposes including radioactive waste treatment, tritium production, and neutron factories for materials studies. Since the fractional beam losses must be in the 10{sup {minus}}5 to 10{sup {minus}}6 range and are clearly subject to operational variables, the design engineers are forced to develop concepts which combine maintainability under radioactivity conditions, high availability, and very high reliability while dealing with the operating parameters resulting from CW operation. Several design solutions to selected problems are presented.
Date: June 1, 1993
Creator: Liska, D.; Carlisle, L.; McCauley, G.; Ellis, S.; Ilg, T. & Smith, P.
Partner: UNT Libraries Government Documents Department

Irradiation study on GEM IPC preamp/shaper

Description: The Preamplifier/Shaper Integrated Circuit for the GEM Interpolating Pad Chamber (IPC), designed by Paul. O`Connor, Brookhaven National Laboratory is for amplifying the charge signal from the Pad cathodes into a voltage pulse which goes to the Analog Random Access Memory (ARAM) integrated circuit. The GEM IPC integrated circuit has a SemiGaussian voltage pulse output with a 30ns shaping time. The integrated circuits were fabricated using Harris Semiconductors AVLSI1-RA process in-order for the electronics on the wafer to survive up to 2 mad of ionizing radiation during its operation life time. The details of the electronics on the GEM IPC integrated circuits is explained in the design memorandum by Paul. O`Connor. The purpose of this study is to determine the ability of the electronics on this IC fabricated using the above process to withstand ionizing radiation up to the above mentioned dose level.
Date: January 1, 1995
Creator: Kandasamy, A.
Partner: UNT Libraries Government Documents Department

Linearity of photoconductive GaAs detectors to pulsed electrons

Description: The response of neutron damaged GaAs photoconductor detectors to intense, fast (50 psec fwhm) pulses of 16 MeV electrons has been measured. Detectors made from neutron damaged GaAs are known to have reduced gain, but significantly improved bandwidth. An empirical relationship between the observed signal and the incident electron fluence has been determined.
Date: December 31, 1995
Creator: Ziegler, L.H.
Partner: UNT Libraries Government Documents Department

SVX/silicon detector studies

Description: AC coupled silicon detectors, being used for the DO upgrade, may have substantial voltage across the coupling capacitor. Failed capacitors can present {approximately}50 V to the input of the SVX, Silicon Vertex, device. We measured the effects that failed detector coupling capacitors have on the SVXD (rad soft 3{mu}m), SVXH (rad hard 1.2{mu}m), and SVXIIb (rad soft 1.2{mu}m) amplifier / readout devices. The test results show that neighboring channels saturate when an excessive voltage is applied directly to a SVX channel. We believe that the effects are due to current diffusion within the SVX substrate rather than surface currents on the detectors. This paper discusses the magnitude of the saturation and a possible solution to the problem.
Date: November 1, 1995
Creator: Bagby, L.; Johnson, M.; Lipton, R. & Gu, W.
Partner: UNT Libraries Government Documents Department

Radiation hardness assurances categories for COTS technologies

Description: A comparison of the radiation tolerance of three commercial, and one radiation hardened SRAM is presented for four radiation environments. This work has shown the difficulty associated with strictly categorizing a device based solely on its radiation response, since its category depends on the specific radiation environment considered. For example, the 3.3-V Paradigm SRAM could be considered a radiation-tolerant device except for its SEU response. A more useful classification depends on the methods the manufacturer uses to ensure radiation hardness, i.e. whether specific design and process techniques have been used to harden the device. Finally, this work has shown that burned-in devices may fail functionally as much as 50% lower in total dose environments than non-burned-in devices. No burn-in effect was seen in dose-rate upset, latchup, or SEE environments. The user must ensure that total dose lot acceptance testing was performed on burned-in devices.
Date: March 1, 1997
Creator: Hash, G.L.; Shaneyfelt, M.R.; Sexton, F.W. & Winokur, P.S.
Partner: UNT Libraries Government Documents Department

Investigation of the possibility of using continuous electron beams for electromotive liner hardening. Final report (Task 3)

Description: Continuous laser and electron beams are presently used for surface hardening of steel and cast iron articles. The main advantage of the sources of continuous electron beams over lasers is their high (over 90%) efficiency of conversion of an electric energy to the energy of an electron beam. A promising version of electron-beam system is that including a plasma electron source of the type developed at the Institute of High Current Electronics (IHCE, Tomsk). This type of source has a long lifetime and can operate at a poor vacuum ({approximately} 10{sup {minus}2} torr) in the working chamber. Owing to this they are successfully used for electron-beam welding, melting-on of hardening coatings, and surface hardening of machine parts. The goal of the present work is to elucidate whether it is possible to use a plasma-cathode continuous electron gun for hardening the internal surface of cast iron liners.
Date: November 1, 1998
Creator: Proskurovsky, D.I.; Rotshtein, V.P.; Rempe, N.G.; Osipov, I.V. & Goncharenko, I.M.
Partner: UNT Libraries Government Documents Department

Radiation hardness measurements of new permanent magnet materials for high-intensity linac applications

Description: This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The radiation resistance of samples of high-strength samarium cobalt permanent-magnet material has been studied. Samples of commercially available material were obtained from four different manufacturers. The remanent field of the samples was measured before and after the samples were irradiated with neutrons produced at the beam stop of the Los Alamos Neutron Science Center (LANSCE) proton accelerator.
Date: December 31, 1998
Creator: Barlow, D. B.; Kraus, R. H. & Borden, M. J.
Partner: UNT Libraries Government Documents Department

MECHANICAL PROPERTIES AND MICROSTRUCTURE IN LOW ACTIVATION MARTENSITIC STEELS F82H AND OPTIMAX AFTER 800 MEV PROTON IRRADIATION

Description: Low-activation martensitic steels, F82H (mod.) and Optimax-A, have been irradiated with 800-MeV protons up to 5.9 dpa. The tensile properties and microstructure have been studied. The results show that radiation hardening increases continuously with irradiation dose. F82H has lesser irradiation hardening as compared to Optimax-A in the present work and DIN1.4926 from a previous study. The irradiation embrittlement effects are evident in the materials since the uniform elongation is reduced sharply to less than 2%. However, all the irradiated samples ruptured in a ductile-fracture mode. Defect clusters have been observed. The size and the density of defect clusters increase with the irradiation dose. Precipitates are amorphous after irradiation.
Date: October 1, 1999
Creator: DAI, Y. & AL, ET
Partner: UNT Libraries Government Documents Department

Aging and Radiation Effects in Stockpile Electronics

Description: It is likely that aging is affecting the radiation hardness of stockpile electronics, and we have seen apparent examples of aging that affects the electronic radiation hardness. It is also possible that low-level intrinsic radiation that is inherent during stockpile life will damage or in a sense age electronic components. Both aging and low level radiation effects on radiation hardness and stockpile reliability need to be further investigated by using both test and modeling strategies that include appropriate testing of electronic components withdrawn from the stockpile.
Date: March 25, 1999
Creator: Hartman, E.F.
Partner: UNT Libraries Government Documents Department