Abstract: A detection system operating on a scalable Radiation Sensor Unit (RSU) data stream employs a detection module triggering an alarm based on fee dynamic temporal features of gross count. Two spectroscopic buffers, one holding a long-term background and one holding the integrated detection event data are passed on for identification. The detector data incorporates sets of counts measured at channelized gamma energies. Each multi-channel data set is reduced to highly accurate peak locations. The absolute energy of the peaks is determined using innovative techniques and the background peaks and other secondary peaks are eliminated to provide a concise list of corrected source peak locations and intensities. This, together with spectral region analysis results is used with pattern recognition algorithms to identify fee source isotope or combination of isotopes from a standard library.

Abstract: A detection system operating on a scalable Radiation Sensor Unit (RSU) data stream employs a detection module triggering an alarm based on fee dynamic temporal features of gross count. Two spectroscopic buffers, one holding a long-term background and one holding the integrated detection event data are passed on for identification. The detector data incorporates sets of counts measured at channelized gamma energies. Each multi-channel data set is reduced to highly accurate peak locations. The absolute energy of the peaks is determined using innovative techniques and the background peaks and other secondary peaks are eliminated to provide a concise list of corrected source peak locations and intensities. This, together with spectral region analysis results is used with pattern recognition algorithms to identify fee source isotope or combination of isotopes from a standard library.

Abstract: An apparatus and method for holding a thin workpiece such as a semiconductor wafer for operations which require the workpiece to have a high degree of planarity such as photolithographic printing includes positioning the workpiece onto a planar holding face comprising the points of a multiplicity of regularly spaced-apart substantially parallel pins with a thin rim encompassing all pins to contain a vacuum in the region adjacent to the workpiece. The small abutting area of each pinpoint abutment reduces the probability of dirt particles collecting on the holding face and provides a high thrust pressure to dislodge dirt particles interposed between the abutment and the workpiece. A small amount of lateral motion is imparted to the workpiece when it first contacts the holding face to brush off any dirt particles on the abutments.

Abstract: An apparatus and method for holding a thin workpiece such as a semiconductor wafer for operations which require the workpiece to have a high degree of planarity such as photolithographic printing includes positioning the workpiece onto a planar holding face comprising the points of a multiplicity of regularly spaced-apart substantially parallel pins with a thin rim encompassing all pins to contain a vacuum in the region adjacent to the workpiece. The small abutting area of each pinpoint abutment reduces the probability of dirt particles collecting on the holding face and provides a high thrust pressure to dislodge dirt particles interposed between the abutment and the workpiece. A small amount of lateral motion is imparted to the workpiece when it first contacts the holding face to brush off any dirt particles on the abutments.