Studies of Prototype High-Gain Microchannel Plate Photomultiliers

Micro-diffraction based crystallography is essential to the design and development of many classes of ‘crafted materials’. Although the scanning electron microscope can provide crystallographic information with high spatial resolution, its current utility is severely limited by the low sensitivity of existing diffraction techniques (ref: Dingley). Previously, Joy showed that energy filtering increased contrast and pattern visibility in electron channelling. This present paper discribes the effect of energy filtering on EBSP sensitivity and backscattered SEM imaging.The EBSP detector consisted of an electron energy filter, a microchannel plate detector, a phosphor screen, optical coupler, and a slow scan CCD camera. The electrostatic energy filter used in this experiment was constructed as a cone with 5 coaxial electrodes. The angular field-of-view of the filter was approximately 38°. The microchannel plate, which was the initial sensing component, had high gain and had 50% to 80% detection efficiency for the low energy electrons that passed through the retarding field filter.

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Imaging at Soft X-ray Wavelengths with High-Gain Microchannel Plate Detector Systems

10.1117/12.936618 ◽

1986 ◽

Author(s):

J.Gethyn Timothy

Keyword(s):

High Gain ◽

Microchannel Plate ◽

X Ray

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The Design of the AZO Conductive Layer on Microchannel Plate

Nanoscale Research Letters ◽

10.1186/s11671-021-03515-0 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Yuman Wang ◽

Shulin Liu ◽

Baojun Yan ◽

Ming Qi ◽

Kaile Wen ◽

...

Keyword(s):

High Resistance ◽

Atomic Layer ◽

High Gain ◽

Test System ◽

Microchannel Plate ◽

Conductive Layer ◽

Conductive Material ◽

Layer Deposition ◽

Zn Content ◽

Working Resistance

AbstractWhen the resistivity of the AZO conductive layer is within the MCP resistance requirement, the interval of the Zn content is very narrow (70–73%) and difficult to control. Aiming at the characteristics of the AZO conductive layer on the microchannel plate, an algorithm is designed to adjust the ratio of the conductive material ZnO and the high resistance material Al2O3. We put forward the concept of the working resistance of the MCP (i.e., the resistance during the electron avalanche in the microchannel). The working resistance of AZO-ALD-MCP (Al2O3/ZnO atomic layer deposition microchannel plate) was measured for the first time by the MCP resistance test system. In comparison with the conventional MCP, we found that the resistance of AZO-ALD-MCP in working state and non-working state is very different, and as the voltage increases, the working resistance significantly decreases. Therefore, we proposed a set of analytical methods for the conductive layer. We also proposed to adjust the ratio of the conductive material of the ALD-MCP conductive layer to the high-resistance material under the working resistance condition, and successfully prepared high-gain AZO-ALD-MCP. This design opens the way for finding better materials for the conductive layer of ALD-MCP to improve the performance of MCP.

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Low - Voltage Scanning Electron Microscopy Imaging, Secondary and Backscatter, With Microchannel Plate Detector

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180963 ◽

1990 ◽

Vol 48 (1) ◽

pp. 442-442

Author(s):

Galen Powers ◽

Ray Cochran

Keyword(s):

Low Voltage ◽

Beam Current ◽

Microchannel Plate ◽

Normal Operation ◽

Microscopy Imaging ◽

Backscatter Signal ◽

Vacuum Interface ◽

Width Measurements ◽

Working Distance ◽

Beam Currents

The capability to obtain symmetrical images at voltages as low as 200 eV and beam currents less than 9 pico amps is believed to be advantageous for metrology and study of dielectric or biological samples. Symmetrical images should allow more precise and accurate line width measurements than currently achievable by traditional secondary electron detectors. The low voltage and current capability should allow imaging of samples which traditionally have been difficult because of charging or electron beam damage.The detector system consists of a lens mounted dual anode MicroChannel Plate (MCP) detector, vacuum interface, power supplies, and signal conditioning to interface directly to the video card of the SEM. The detector has been miniaturized so that it does not interfere with normal operation of the SEM sample handling and alternate detector operation. Biasing of the detector collection face will either add secondaries to the backscatter signal or reject secondaries yielding only a backscatter image. The dual anode design allows A−B signal processing to provide topological information as well as symmetrical A+B images.Photomicrographs will show some of the system capabilities. Resolution will be documented with gold on carbon. Variation of voltage, beam current, and working distance on dielectric samples such as glass and photoresist will demonstrate effects of common parameter changes.

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Equivalent Noise Dose Obtained Through Hearing Aids in the Classrooms of Hearing-Impaired Children

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.2103.147 ◽

1990 ◽

Vol 21 (3) ◽

pp. 147-150

Author(s):

Ronald A. Wilde

Keyword(s):

Hearing Aids ◽

High Gain ◽

Hearing Impaired ◽

Deaf Children ◽

Impaired Children ◽

Very High ◽

Hearing Impaired Children

A commercial noise dose meter was used to estimate the equivalent noise dose received through high-gain hearing aids worn in a school for deaf children. There were no significant differences among nominal SSPL settings and all SSPL settings produced very high equivalent noise doses, although these are within the parameters of previous projections.

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