Radiation detection is accomplished by sensing the piezoelectric response to the expansion and contraction in a crystal element due to the heating effect of the carrier energy to be sensed. Sensitivity to a subcarrier is enhanced by utilizing a frequency (of interrupted or continuous wave subcarrier) corresponding with a mechanical resonance frequency of the crystal element. The device is analogous to a conventional resonant r.f. detector element. Uses to which such prior art devices are applied may also be served with the class of inventive devices. Such uses include frequency standards, channel selectors, etc.
An infrared detection system is described that embodies an improved glass window for transmitting infrared radiation to a heat sensitive detection element in the system. The window is produced from a glass consisting essentially, in percent by weight on an oxide basis, of 25-50% GeO.sub.2, 10-50% La.sub.2 O.sub.3, 5-50% Ta.sub.2 O.sub.5 and 2-20% ZnO. Such glasses are hard and abrasion resistant, have moderate coefficients of thermal expansion and have a substantial transmission for infrared radiation in the wavelength range of 5 to 6 microns.
A process for the formation of a force field comprising cooling at least one crystal selected from potassium tartrate, cesium nitrate, rubidium nitrate, tartaric acid, cadmium nitrate and thorium nitrate to a temperature below about 110K. The force field comprises an electric field and a mass attraction field which maintains its intensity over long time periods. A method is also provided for establishing a force field at a location remote from the cooled crystal by means of an electrical connection to the cooled crystal by an insulated electrical conductor. The invention includes a device for forming the force field.
A process for the formation of a force field comprising cooling at least one crystal selected from potassium tartrate, cesium nitrate, rubidium nitrate, tartaric acid, cadmium nitrate and thorium nitrate to a temperature below about 110K. The force field comprises an electric field and a mass attraction field which maintains its intensity over long time periods. The crystal is encapsulated in, e.g., nonconductive epoxy.
A large area pyroelectric joulemeter for measuring the pulsed beam output of a laser. The joulemeter employs a pyroelectric detector element with front and rear conductive surfaces forming electrodes, a relatively massive mounting block with relatively high thermal conductivity and an epoxy adhesive for securing the detector element to the mounting block, the epoxy having relatively high thermal conductivity so that heat can be quickly dissipated out of the detector element. An internal recess in the mounting block accommodates a trimming capacitor and resistor for adjusting the voltage sensitivity of the detector assembly to a constant value. The detector assembly is removably installed within an outer housing having a main base portion and a removable bezel.
