On-Chip Terahertz Detector Designed with Inset-Feed Rectangular Patch Antenna and Catadioptric Lens

This study proposes an on-chip terahertz (THz) detector designed with on-chip inset-feed rectangular patch antenna and catadioptric lens. The detector incorporates a dual antenna and dual NMOSFET structure. Radiation efficiency of the antenna reached 89.4% with 6.89 dB gain by optimizing the antenna inset-feed and micro-strip line sizes. Simulated impedance was 85.55 − j19.81 Ω, and the impedance of the antenna with the ZEONEX horn-like catadioptric lens was 117.03 − j20.28 Ω. Maximum analyzed gain of two on-chip antennas with catadioptric lens was 17.14 dB resonating at 267 GHz. Maximum experimental gain of two on-chip patch antennas was 4.5 dB at 260 GHz, increasing to 10.67 dB at 250 GHz with the catadioptric lens. The proposed on-chip rectangular inset-feed patch antenna has a simple structure, compatible with CMOS processing and easily implemented. The horn-like catadioptric lens was integrated into the front end of the detector chip and hence is easily molded and manufactured, and it effectively reduced terahertz power absorption by the chip substrate. This greatly improved the detector responsivity and provided very high gain. Corresponding detector voltage responsivity with and without the lens was 95.67 kV/W with NEP = 12.8 pW/Hz0.5 at 250 GHz, and 19.2 kV/W with NEP = 67.2 pW/Hz0.5 at 260 GHz, respectively.

GAIN PREDICTION THEORY OF SINGLE FOIL GAS ELECTRON MULTIPLIER DETECTOR

Gain prediction theory of single foil Gas Electron Multiplier detector was developed. Gas electron multiplier (GEM) detector with single foil was developed. Soft X-ray spectra with an energy of 5.9 keV emitted by the isotope Fe-55 were measured. On this basis, the dependence of gain and energy resolution from the detector voltage was determined. The simple theory of gain dependence on various detector parameters was developed. Preliminary results of the study confirmed the potential usefulness of the GEM detector as a substitute for the multiwire proportional chamber.

Quantitative Determination of Formic, Acetic, Propionic, and Butyric Acids by Gas Chromatography

Volatile acids were separated from food samples by a steam distillation according to AOAC methods, neutralized, and evaporated to dryness. The acids were then liberated with an equivalent amount of 0.5N dichloroacetic acid in acetone. Three microliters of the acetone solution containing from 0.1 to 1.0 mg of each acid per ml was injected directly into the column of the gas chromatograph. Experimental conditions were: Six-foot glass column; support, Anakrom 110/120 mesh; substrate, 10.5% ethyleneglycol adipate and 1.75% phosphoric acid; column temperature, 100°C; Sr90 detector temperature, 170°C; vaporizer temperature, 200°C; detector voltage, 1400 volts; argon flow rate, 50 ml per minute. Peak heights and responses relative to methyl enanthate (heptanoate) as an internal standard were used to calculate concentrations of the individual acids. Recoveries from known mixtures were 95—105% for lower concentrations of the acids and 97—101% for higher concentrations. Results of analyses of frozen whole eggs and of frozen fish fillets agreed with results by AOAC methods.