Kla Tencor Corporation

Derek Mackay

Kai Cao

Paul Donders

Jamie Michael Sullivan

Ralph C Wolf

Grace H Chen

Jeongsik Lim

A multi-channel photomultiplier tube (PMT) detector assembly includes a photocathode. The detector assembly includes a first dynode channel including a first set of dynode pathways. The first set of dynode pathways include a plurality of dynode stages configured to receive a first portion of the photoelectrons and direct a first amplified photoelectron current onto a first anode. The detector assembly includes an additional dynode channel including an additional set of dynode pathways. The additional set of dynode pathways includes a plurality of dynode stages configured to receive an additional portion of the photoelectrons and direct an additional amplified photoelectron current onto an additional anode. The detector assembly includes a grid configured to direct the first portion of the photoelectrons to one or more of the first set of pathways and an additional portion of the photoelectrons to one or more of the additional set of pathways.

Multi-channel photomultiplier tube assembly

A bias-variant photomultiplier tube (PMT) includes a photocathode that when operating absorbs photons and emits photoelectrons responsive to the absorbed photons. The bias-variant PMTO also includes a plurality of dynodes that receive the photoelectrons emitted by the photocathode. The plurality of dynodes include a first pair of dynodes having a first bias difference and at least a second pair of dynodes having a second bias difference. The second bias difference is greater than the first bias difference. The bias-variant PMTO also includes an anode to receive photoelectrons directed from the plurality of dynodes.

Bias-variant photomultiplier tube

An internal portion of a photomultiplier tube (PMT) having a reflective photocathode array, and a method for manufacturing the same, are provided. The internal portion of the PMT comprises the reflective photocathode array and at least one dynode structure corresponding to the array of reflective photocathodes. Each reflective photocathode receives light and from the light, generates photoelectrons which then travel towards the at least one dynode structure. Upon the photoelectrons making contact with the at least one dynode structure, the photoelectrons are multiplied.

Photomultiplier tube (PMT) having a reflective photocathode array

Disclosed are apparatus and methods for inspecting or measuring a specimen. An incident beam is directed across a plurality of consecutive scan portions of a specimen so that an output beam profile from each scan portion is consecutively collected by a photomultiplier tube (PMT), and the scan portions include at least one or more first scan portions and a next scan portion that is scanned after the one or more first scan portions. After or while the incident beam is directed to the one or more first scan portions of the specimen, an output signal for each first scan portion is obtained based on the output beam profile that is collected by the PMT for each first scan portion. An expected output beam profile for the next scan portion is determined based on the output signal that is obtained for each one or more first scan portions. As the incident beam is directed towards the next scan portion, a gain input to the PMT for the next scan portion is set based on the expected output beam profile so that the gain for such next scan portion results in a measured signal at the PMT that is within a predefined specification of the PMT or other hardware components that receive a measured signal from the PMT.

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Menlo Park, CA, United States of America

Derek Mackay