B. Azais

Investigation and Analysis of LM124 Bipolar Linear Circuitry Response Phenomenon in Pulsed X-Ray Environment

Analog Transient Radiation Effects in Electronics (ATREE) induced by high dose-rate X-ray pulses are investigated using a flash X-ray facility. The ATREEs induced in a LM124 operational amplifier configured in three different bias configurations are investigated. A predictive methodology, based upon a previously developed ASET simulation tool, is used to model the ATREE phenomena. A semiempirical physical model is used to perform the correlation between the duration of the parasitic pulse signal induced in the LM124 and an equivalent value of the high dose-rate X-ray pulse level.

Accelerated Irradiation Method to Study Synergy Effects in Bipolar Integrated Circuits

An accelerated irradiation technique is used to study dose-ASET synergy effects. The impact of TID on SET is found to be identical when the dose rate is switched from high to low or from low to high.

Development of a New Methodology to Model the Synergistic Effects Between TID and ASETs

A high level model is developed using circuit analysis to predict the synergy effect observed on a three stages operational amplifier. This model makes possible to explain and to predict the analog single event transients propagation in circuitry. The effect of total ionizing dose is taken into account by varying the model parameters using the monitoring of the usual supply current induced degradation of the operational amplifier.

Modeling and Investigations on TID-ASETs Synergistic Effect in LM124 Operational Amplifier From Three Different Manufacturers

The synergistic effect between Total Ionizing Dose (TID) and Analog Single Event Transient (ASET) in LM124 operational amplifiers (opamps) from three different manufacturers is investigated. This effect is clearly identified on only two manufacturers by three, highlighting manufacturer dependent. In fact, significant variations were observed on both the TID sensitivity and the ASET response of LM124 devices from different manufacturers. Hypotheses are made on the cause of the differences observed. A previously developed ASET simulation tool is used to model the transient response. The effects of TID on devices are taken into account in the model by injecting the variations of key electrical parameters obtained during Co60 irradiation. An excellent agreement is observed between the experimental responses and the model outputs, independently of the TID level, the bias configuration and the manufacturer of the device.

Impact of Switched Dose-Rate Irradiation on the Response of the LM124 Operational Amplifier to Pulsed X-Rays

The Synergistic effect between TID and ATREEs (Analog Transient Radiation Effects on Electronics) in an operational amplifier (opamp) (LM124) is investigated for three different bias configurations. An accelerated irradiation technique is used to study these synergistic effects. The impact of TID on ATREEs is found to be identical regardless of whether the irradiation is performed at low dose rate or whether the dose rate is switched from high to low using the Dose Rate Switching (DRS) technique. The correlation between the deviations of the opamps electrical parameters and the changes of ATREE widths is clearly established.

Pulsed X-ray and /spl gamma/ rays irradiation effects on polarization-maintaining optical fibers

We studied the sensitivities at 1.55 /spl mu/m of three polarization-maintaining (PM) and three unstressed single-mode (SM) optical fibers under pulsed X-ray (/spl sim/1 MeV) and steady-state /spl gamma/-ray (/spl sim/1 MeV) radiation. Our results showed no differential radiation-induced attenuation (RIA) between the two orthogonal polarization axes of PM fibers for times ranging from 10/sup -6/ s to 100 s after ionization pulse (dose <1 kGy(SiO/sub 2/), dose rate >1MGy/s). The two inner cladding phosphorus-codoped PM fibers and their corresponding SM fibers exhibited the same RIA levels and kinetics after both irradiation types. Their radiation responses could be explained by their compositions and by the properties of the absorbing phosphorus-related defects generated in the light guiding region (core and inner cladding). The inner cladding fluorine-codoped PM fiber showed radiation-tolerant properties compared with its SM counterpart. We assumed, therefore, that the outer stress applying region dopants could have an impact on the fiber radiation sensitivity under both irradiation types. More particularly, we showed that the cladding phosphorus-codoping far from the light guiding region reduces the RIA related to the germanium defects in the fiber core. This effect could be due to the donor nature of the double phosphorus-oxygen bond and could be exploited to design radiation-hardened polarization-maintaining and single-mode optical fibers.

Study of manufacturing variations impact on TID-ATREEs synergistic effect in LM124 operational amplifier

The impact of different manufacturing process and designs on the TID-ATREEs synergistic effect is investigated in the LM124 operational amplifier (opamp) from three different manufacturers. Significant variations were observed on both the Total Ionizing Dose (TID) sensitivity and the Analog Transient Effects on Electronics Effects (ATREE) responses of LM124 devices from different manufacturer. The ATREEs are produced by high dose-rate X-ray pulses using a flash X-ray facility. ATREE modeling results were performed using a previously developed simulation tool.

Study and Modeling of the Impact of TID on the ATREE Response in LM124 Operational Amplifier

Shapes of ATREEs (Analog Transient Radiation Effects on Electronics) in a bipolar integrated circuit change with exposure to Total Ionizing Dose (TID) radiation. The impact of TID on ATREEs is investigated in the LM124 operational amplifier (opamp) from three different manufacturers. Significant variations are observed on the ATREE responsesfrom different manufacturers. The ATREEs are produced by pulsed X-ray experiments. ASET laser mappings are performed to highlight the sensitive bipolar transistors, explaining the ATREE phenomena variations from one manufacturer to another one. ATREE modeling results are presented using a previously developed simulation tool. A good agreement is observed between experimental ATREE responses and model outputs whatever the TID level, the prompt dose level, the amplifier configuration and the device manufacturer.

The Role of Feedback Resistors and TID Effects in the ASET Response of a High Speed Current Feedback Amplifier

The influence of external circuit designs on ASET shapes in a high speed current feedback amplifier (CFA) (AD844) is investigated by means of the pulsed laser single event effect (PLSEE) simulation technique. Changes of the feedback resistors modify circuits electrical parameters such as closed-loop gain and bandwidth, affecting amplifier stability and so ASET shapes. Qualitative explanations based on general electronic rules and feedback theories enable the understanding of a CFA operation establishing a correlation between the evolution of external feedback resistor values and ASET parameters. TID effects on the ASET sensitivity in AD844 CFA are also investigated in this work highlighting different behaviors according to the impacted bipolar transistor in the integrated circuit.

Investigation of Flip-Flop Effects in a Linear Analog Comparator-With-Hysteresis Circuit

The impact of the positive feedback loop on analog single event transient (ASET) shapes was investigated for a comparator-with-hysteresis circuit. Simulation based on previous developed ASET simulation tool is used to model the impact of the power supply voltage, the input voltage level and the injected energy. Simulation results show that these kinds of circuits are sensitive to flip-flop effects. This phenomenon occurs if the input voltage is in the hysteresis band range. In this case, simulations show that the ASET can latch the output into a non-desired state by changing the state of the circuit on his transfer characteristic curves. Laser experiments were conducted and show that the simulation outputs are in agreement with the experimental collected data.