Noran Instruments, Inc.

Thermo Electron Scientific Instruments Corporation

Steven J Foote

Jon J McCarthy

Justin D Morrow

Minoru Shinohara

An embodiment of a shutter assembly is described that comprises a support structure with a number of stations and operatively coupled to a motor configured to translate each of the stations to a position in front of a detector, wherein a first station comprises a first aperture, a first charged particle filter, and a first window; and a second station comprises a second aperture larger than the first aperture, a second charged particle filter, and a second window thinner than the first window.

Shutter assembly for x-ray detection

A two-piece collimator for use in high takeoff angle energy dispersive spectroscopy (EDS) is provided. The two-piece collimator includes a base section and an extension section. The collimator base section may be attached rigidly to the end of an EDS detector tube. The collimator extension section is removably attached to and extends from the base section. Apertures through the base and extension sections are easily aligned with each other and with an EDS detector. The length of the collimator extension section is preferably selected such that the distal end of the extension section extends below the bottom of an upper pole piece of an electron microscope in which the collimator is employed. A two-piece collimator in accordance with the present invention effectively reduces stray radiation, including back scattered electrons, which may cause artifacts in a detected EDS X-ray spectrum. Alternatively, a collimator in accordance with the present invention may be used in combination with an existing pole piece insert collimation device by removing the extension section from the two-piece collimator.

Collimator for high takeoff angle energy dispersive spectroscopy (EDS)

An improved X-ray spectrometer detector system includes a mechanical cooling system with a compressor connected by supply and return lines to a cryocooler connected to an X-ray dispersive spectrometer detector for an electron microscope. Within a housing containing a cryocooler heat exchanger, a heat sink thermal mass is thermally connected to a cold finger heat conducting structure which has the X-ray detector mounted at its distal end. The housing insulates the cryocooler heat exchanger and the heat sink from the external ambient. The compressor unit is operated to cool the detector to a desired low operating temperature at which precision measurements may be made. When such measurements are to be made, the compressor is turned off to minimize vibrations that could interfere with X-ray detector measurements or the operation of the electron microscope. The total heat capacity of the thermal mass of the heat sink is sufficient to cause the temperature of the detector to increase gradually while the compressor is turned off to allow a long period of time during which precision measurements may be made without any mechanical vibrations being introduced into the system from active refrigeration. When a temperature of the detector exceeds a higher threshold temperature, the compressor may automatically be turned back on to cool the detector down again to its desired operating range.

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Middleton, WI, United States of America

Steven J Foote