THE COMPETE DETECTOR SYSTEM

• EXCELLENT LOW KV PERFORMANCE
• GOOD ATOMIC NUMBER RESOLUTION
• HIGH SPATIAL RESOLUTION
• OPERATES AT ALL PRESSURES
• COMPOSITION OR TOPOGRAPHY
• LOW NOISE

• SENSITIVE CL DETECTOR
• 300-650nm STANDARD

• BRIGHT OR DARK FIELD WORK
• HIGH RESOLUTION

CENTAURUS uses a new design of scintillator detector (patented). This design gives high sensitivity, particularly at low kVs and therefore the scintillator element may be made quite small whilst still achieving excellent results.
Its low kV performance makes imaging possible down to 0.5KeV. This is considerably lower than most users will ever require. However, its main low kV applications will be around 1.5kV. This is the point where normal charging problems virtually disappear.

CENTAURUS may therefore be used for imaging totally uncoated specimens with little risk of charging. This low kV operation is particularly important for beam sensitive specimens such as semiconductors which may be damaged by the use of higher voltages.

CENTAURUS is also very efficient at high kVs. Its tip, only 4mm in thickness, allows a very short working distance to be used. This in turn helps achieve high resolution images.

The shape of its tip virtually overcomes the usual problems of other scintillator detectors where the image seen is a mixture of both compositional and topography. The topographic content has been almost eliminated but by partially retracting the detector the topographic image may be obtained. A Topo latch is provided to hols the detector in the partially retracted position CENTAURUS has produced excellent results in FE SEMs, where high resolution is paramount. Its high sensitivity gives low noise pictures at very small probe currents.
It has also had great success in “Environmental” or “Low Vacuum” SEMs. In these, the electrons leaving the specimen are significantly retarded

BS Image at 1.5kV of “Sand Dollar” uncoated”

tip has a mirror at the end of a light guide. It has an increased thickness, 10mm, to increase its sensitivity. This is necessary due to the general low light level produced by CL specimens. The tip may be perated very close to the specimen thereby collecting the photons from a large solid angle. The spectral response is limited to that of the photomultiplier tube used for Backscattered collection, 350-650nm Extended range tubes may be fitted where response into the red region is required.

Interchangeable BS &CL tips

If an extended tube, 185-850nm is used, there will be a small drop in Backscattered sensitivity. An infrared tube may also be fitted, but in this case, Backscattered imaging may no longer be viable. Note that although this tube is specified from 400-1200nm, it is very insensitive except near its peak of 800nm.

STEM
To use CENTARUS as a transmission detector, a special STEM tip is fitted beneath the specimen in an inverted position. Electrons therefore pass through the thin specimen before reaching the scintillator. With the tip directly beneath the specimen, a Bright Field is received. With the tip partially retracted so that it is no longer in direct line with the beam, a Dark Field image can be seen. To hold the transmission grids, a special purpose Multi STEM Grid Holder is available for use with this detector. It is designed to hold up to 12 standard transmission specimens.

Multi Stem Grid

To further enhance the suitability of CENTAURUS, K.E.Developments produce a range of Optical Surveillance Products (OSPs) specifically designed to give the operator a view of the interior of the chamber, even when the SEM operating. This helps to speed up specimen exchange and the specimen brought into operating position whilst the SEM is in the vacuum pump period.

Chamber view using OSP

Cloth image at 1.3kV

K.E.Developments are continually striving to keep their products at the leading edge of current technology. The product supplied may therefore differ in detail to that described in this brochure.

Solid at 5kV