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OwnerHorst William Kueppersinventor
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A technique for inspecting a quartz or other cut piezoelectric crystal to determine its angle of peak response to an incident beam of X-radiation is described. A reference surface of the crystal is stepped with respect to the beam through equal angular intervals, and the output of a scintillation counter responsive to the accumulated reflected radiation pulses from the crystal is sampled at the end of each step. Successive samples which exceed a threshold on the leading edge of the crystal response curve during the step scan are stored in a memory, together with the attained values of scanned angle at the end of each step. When a monotonic decrease of such stored samples over at least two successive steps is detected, the stored sample occurring two steps previous to such detection is retrieved from memory, and is multiplied by first and second fractions to yield upper and lower boundaries of a predetermined "valid data" range. When the succeeding samples have decreased in amplitude to the upper boundary of such range on the trailing edge of the crystal response, the memory is again scanned to retrieve a previously stored pair of samples that occurred on the leading edge of the response characteristic and that straddled the amplitude of the then-occurring sample on the trailing edge. For each such successive pair of retrieved samples, an angle corresponding to an amplitude equal to the amplitude of the then-occurring sample on the trailing edge is derived, and such derived angle is added to the attained angle corresponding to the then-occurring sample on the trailing edge to form a first sum. The first sums occurring over the total number of steps spanning the valid data range on the trailing edge are accumulated and are divided by twice the number of such steps to approximate the peak angle of response of the crystal.
In a machine-instrumented method of determining the angle of peak amplitude response of a radiation-sensitive resonant device to a beam of radiation incident on a first surface of the device as the relative angle between the incident beam and the first surface is swept in a first direction, the improvement which comprises the steps of:
In a machine-instrumented method of determining the angle of peak amplitude response of a radiation-sensitive resonant device to a beam of radiation incident on a first surface of the device as the relative angle between the incident beam and the first surface is scanned in a first direction over the response characteristic of the device, the improvement which comprises the steps of:
In a machine-instrumented method of determining the angle of peak reflection, from a prescribed internal atomic plane of a crystal, of a beam of radiation incident on the atomic plane through a reference surface of the crystal as the relative angle between the incident beam and the reference surface is scanned in a first direction over an angular range encompassing the response characteristic of the crystal to the beam, the improvement which comprises the steps of:
In a machine-instrumented method of determining the angle of peak reflection, from a prescribed internal atomic plane of a piezoelectric crystal, of a beam of radiation directed toward the atomic plane through the reference surface of the crystal as a relative angle between the incident beam and the first surface is swept in a first direction over an angular range encompassing the response characteristic of the crystal to said beam, the improvement which comprises the steps of:
In an apparatus for determining the angle of peak reflection, from a prescribed internal atomic plane of a piezoelectric crystal, of a beam of radiation directed toward the atomic plane through a reference surface of the crystal as the relative angle between the incident beam and the reference surface is scanned over an angular range encompassing the response characteristic of the crystal, wherein the apparatus comprises a detector for measuring the amplitude of reflection from the crystal and means for indicating the instantaneous attained angle of the crystal during the scan, the improvement which comprises, in combination:
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