K2 Summit and K2 Base Direct Detection Camera User's Guide
8
Introduction
IMPORTANT: For Regulatory Compliance and Safety information and instructions
please refer to the Regulatory Pamphlet provided with this product. Review
this document in full before installing and operating this product.
The K2 Summit™ Direct Detection Camera is a new type of camera for TEM. The camera
contains a direct detection transmission CMOS detector, which gives the highest resolution
images of any electron-imaging sensor available today. The camera runs in a mode constantly
collecting images at 400 frames per second. The camera then, through a high-bandwidth link,
passes these frames at full speed to dedicated high-throughput hardware designed for the
express purpose of processing these images in real time. By collecting and processing full-
frame images so quickly the detector can identify and record individual electron events
(counting) as they reach the sensor. By counting every single electron event, the camera can
eliminate the background noise typically seen in devices that simply read out the charge
deposited by an electron striking a piece of silicon. By removing this source of noise, the
camera can offer higher image quality and sensitivity than previously available in an electron-
imaging device.
This device is also capable of operating in a Super-Resolution mode. In this mode, the sensor
is able to localize the electron event with sub-pixel accuracy, effectively doubling the number
of pixels available for imaging (from 3838 x 3710 to 7676 x 7420). Again the processing is
all done on full frames in real time as the images are collected. In addition, the camera
employs a pixel design giving radiation hardness 10x greater than any other direct-detection
sensor available (pixel lifetime of >5 billion electrons). K2 Summit also allows Linear read
mode (used on K2 Base™) for high-dose applications.
Why Silicon APS and Counting are Good
Direct Detection sensors are derived from Active Pixel Sensor (APS) technology developed
for digital cameras and cell phones. Like a CCD, an APS is an integrated circuit containing
an array of pixels. But unlike a CCD, readout does not require pixel-to-pixel charge transfer.
Each pixel contains a photo detector and active amplifier that is addressed and read-out
individually. The K2 Direct Detection APS is designed using proprietary design and layout
techniques that make it radiation resistant enough to detect electrons without significant
damage to the sensor. K2 Direct Detection APS is based on CMOS semiconductor
technology and produced at commercial semiconductor foundries with manufacturing of
more advanced (smaller) nodes resulting in increased radiation resistance.
Direct Detection was used in high-energy particle physics and other fields before coming to
EM. A major challenge for EM uses is that energy and charge deposited by the high-energy
electrons quickly damage most sensor types, causing a rapid deterioration of the image
quality. CCD sensors have been used for direct detection, although only for a short period of
time before failure. Early development (“first generation”) EM Direct Detectors had poor
radiation hardness, meaning poor ease of use and the need for a second “set up” camera for
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