Editorials

Polar Ice Thickness Measurements Customer Case The customer is an academic researcher in climate change. He wants to record the depth of the permafrost ice sheets in the arctic regions of Canada, Greenland and elsewhere. The change in world climate is directly related to the changes in the thickness of polar ice. Abrupt changes can be a predictor of climatic changes in the world. The measuring apparatus is an ice-penetrating radar mounted on an aircraft flying at 500-600 meters. The radar pulses at 20 kHz Pulse Repeat Frequency (PRF), captures the reflections of groups of 32-64 pulses. Each pulse [...]

Storm Watch / Tornado Radar Customer Case On average, the United States experiences 100,000 thunderstorms each year, causing about 1,000 tornadoes. The customer is trying to determine what meteorological conditions enable a large rotating thunderstorm (a "supercell") to drop a dangerous tornado-funnel. By determining what conditions must exist for the formation of an especially fierce tornado, researchers hope to develop accurate predictions of when and where such a tornado may touch down, giving the people time to evacuate. The customer wants to study tornadoes and other severe-storm features with an X-Band polarimetric Doppler radar. This mobile cloud-profiling radar is [...]

Atmospheric Remote Sensing Customer Case The customer requires a combination of hardware and software ("data system") to do live update sampling, processing, display, and archival of atmospheric measurements using an airborne Lidar system. This system, which continuously emits laser pulses, measures line-of-sight velocity and backscattered signals at a particular range from the aircraft. Real-time performance is necessary to observe the state of the atmosphere and to assess the performance of their instrument. Their requirement is similar to that of laser Doppler anemometry. The signal from the Lidar system will vary continuously with time and the signal waveform will be [...]

Nuclear Decay Experiment Customer Case A customer wants to measure nuclear decay rates of various radioactive isotopes. With each nuclear decay, the isotope under study simultaneously emits a beta particle, which is a high-speed electron, and a gamma particle, which is a high-frequency photon of light. Beta particles are detected with an efficiency of over 90% by a proportional gas counter that surrounds the radioactive isotope. Surrounding only one quarter of the isotope, a sodium iodide scintillator crystal detects gamma particles with about 25% efficiency. When it impinges on the scintillator crystal, a gamma creates a flash of visible [...]

Electron Spin Resonance (ESR) Experiment Customer Case A customer has an Electronic Spin Resonance (ESR) experiment. ESR is based on the fact that the magnetic moment of an electron precesses in an applied magnetic field, not unlike a child's top in a gravitational field, at a well-defined frequency called the Larmor frequency. Electromagnetic radiation at the Larmor frequency, when impinging on such an electron, will be preferentially absorbed. This principle is identical to that employed in Nuclear Magnetic Resonance (NMR), where the atomic nucleus precesses. In NMR, Larmor frequencies are of order 100 MHz. Because the electron is 2000 [...]