We describe the design and results of a wide band C-X cryogenic IF amplifier developed for band 9 (602-720 GHz) of ALMA radio telescopes. A cryogenic 4-12 GHz isolator will be used at the input to improve matching. Several units have been fabricated and its results are presented. The amplifiers utilize HRL InP transistors to achieve a noise temperature of 5.3 K (0.08 dB NF) on average. Gain fluctuations are critical for the project.Values of Allan variance lower than 4.1 10-9 (0.1 s < T < 10 s) have been obtained.

No abstract

The contribution of the electromagnetic field to the electric response of a circuit exposed to high x-ray flux is quantified based on a novel approach which combines both experimental and numerical tools. First, we describe the method used to quantify the ionizing and electromagnetic stress induced by the x-ray beam in free space as well as on the target circuit. Next we show the perturbation resulting from the x-ray irradiation of an analog circuit. Also, we present the effect of an electromagnetic plane wave on the electric response of the circuit. Based on the comparison of experimental results, we demonstrate that electromagnetic fields coupling resulting from photoelectrons produced by the x-ray/circuit interaction is similar to the coupling induced by an external electromagnetic plane wave.Index Terms-Monte-Carlo calculations, particle-in-cell calculations, system generated electromagnetic pulse, transient radiation effects on electronics.

No abstract