High-power operation of a K-band second harmonic gyroklystron

Amplification studies of a two-cavity second-harmonic gyroklystron are reported. A magnetron injection gun produces a 440 kV, 200–245 A, 1 μs beam with an average perpendicular-to-parallel velocity ratio slightly less than 1. The TE011 input cavity is driven near 9.88 GHz and the TE021 output cavity resonates near 19.76 GHz. Peak powers exceeding 21 MW are achieved with an efficiency near 21% and a large signal gain above 25 dB. This performance represents the current state of the art for gyroklystrons in terms of the peak power normalized to the output wavelength squared

Efficient operation of a high-power X-band gyroklystron

Experimental studies of amplification in a two-cavity X-band gyroklystron are reported. The system utilizes a thermionic magnetron injection gun at voltages up to 440 kV and currents up to 190 A in 1-μs pulses. Optimum performance is achieved by tapering the magnetic-field profile. Peak powers of 20 MW in the TE01 mode at 9.87 GHz are measured with calibrated crystals and with methanol calorimetry. Resultant efficiencies are in excess of 31% and large-signal gains surpass 26 dB. The experimental results are in good agreement with simulated results from a partially self-consistent, nonlinear, steady-state code

Canada and The Marshall Plan, June — December 1947

La position et les réactions du Canada au début des discussions du Plan Marshall furent typiques des principales caractéristiques des relations canado-américaines durant l'après-guerre : accommodement des intérêts politiques des Etats-Unis et des intérêts économiques canadiens. Malgré des plans de restriction des importations américaines au Canada afin de réaliser une meilleure balance commerciale, le Canada se montra prêt à proposer un tarif moins discriminatoire en échange d'une réduction du tarif américain et d'une participation au bénéfices du plan Marshall. Lorsque le Congrès américain accepta que des denrées puissent être exportées d'en dehors des Etats-Unis jusqu'à concurrence de 25% des crédits alloués pour le plan, le Canada se vit assuré d'un débouché important pour certaines des ses exportations

Propagation of gamma rays and production of free electrons in air

A new concept of remote detection of concealed radioactive materials has been recently proposed \cite{Gr.Nusin.2010}-\cite{NusinSprangle}. It is based on the breakdown in air at the focal point of a high-power beam of electromagnetic waves produced by a THz gyrotron. To initiate the avalanche breakdown, seed free electrons should be present in this focal region during the electromagnetic pulse. This paper is devoted to the analysis of production of free electrons by gamma rays leaking from radioactive materials. Within a hundred meters from the radiation source, the fluctuating free electrons appear with the rate that may exceed significantly the natural background ionization rate. During the gyrotron pulse of about 10 microsecond length, such electrons may seed the electric breakdown and create sufficiently dense plasma at the focal region to be detected as an unambiguous effect of the concealed radioactive material.Comment: 27 pages, 10 figure

Chaotic synchronization of coupled electron-wave systems with backward waves

The chaotic synchronization of two electron-wave media with interacting backward waves and cubic phase nonlinearity is investigated in the paper. To detect the chaotic synchronization regime we use a new approach, the so-called time scale synchronization [Chaos, 14 (3) 603-610 (2004)]. This approach is based on the consideration of the infinite set of chaotic signals' phases introduced by means of continuous wavelet transform. The complex space-time dynamics of the active media and mechanisms of the time scale synchronization appearance are considered.Comment: 11 pages, 7 figures, published in CHAOS, 15 (2005) 01370

Remote Detection of Radioactive Material using High-Power Pulsed Electromagnetic Radiation

Remote detection of radioactive materials is impossible when the measurement location is far from the radioactive source such that the leakage of high-energy photons or electrons from the source cannot be measured. Current technologies are less effective in this respect because they only allow the detection at distances to which the high-energy photons or electrons can reach the detector. Here we demonstrate an experimental method for remote detection of radioactive materials by inducing plasma breakdown with the high-power pulsed electromagnetic waves. Measurements of the plasma formation time and its dispersion lead to enhanced detection sensitivity compared to the theoretically predicted one based only on the plasma on and off phenomena. We show that lower power of the incident electromagnetic wave is sufficient for plasma breakdown in atmospheric-pressure air and the elimination of the statistical distribution is possible in the presence of radioactive material.ope

Biosolids Fertilization for Dryland Pacific Northwest Wheat Production

The fertilizer value of anaerobically-digested, dewatered biosolids in dryland cereal cropping systems was evaluated at six locations in central and eastern Washington (25 to 35 cm annual precipitation zone). Biosolids were applied at rates of 3 to 20 Mg/ha (approximately 150 to 900 kg N/ha). We measured increases in soil nutrient levels [phosphorus (P), sulfur (S), and zinc (Zn)] with biosolids fertilization that will contribute to increased site productivity for one or more cropping cycles. Biosolids fertilization at 300 kg N/ha produced yields equal to inorganic N fertilizers (anhydrous/aqua ammonia or ammonium nitrate) applied at 55 kg N/ha. Biosolids applied at 300 kg N/ha supplied more than enough N for maximum yield as demonstrated by higher grain N, higher grain N uptake, and lower grain test weight compared to inorganic N fertilization. Increasing the biosolids application rate to 600 kg N/ha reduced grain yield due to lodging and grain shrivel, and resulted in high levels of postharvest soil nitrate-N. Biosolids increased grain production by increasing spike number and kernels per spike. These visual responses were offset by reduced grain kernel weight with biosolids fertilization. We conclude that biosolids rates of approximately 300 kg N/ha will provide maximum benefits for wheat growers in the 25 to 35 cm precipitation zone in the Pacific Northwest. Future research is needed to identify wheat varieties which respond best to biosolids fertilization.Keywords: biosolids application rate, dryland wheat, nitrogen, phosphorus, sulfur, zinc fertilizer value, grain yield, grain N, soil nitrate