Precision Pulse Current Integrator for Beam Measurement
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Solution Overview
Problem
Existing beam current measurement systems using Faraday cups face challenges in accuracy and flexibility, particularly when measuring the currents of two different particle beams, due to offset and gain errors from multiple operational amplifiers, limiting their ability to handle a wide range of beam currents effectively.
Innovation Solution
The precision pulse current integrator (PPCI) system employs a Faraday cup connected to an integration capacitor and a programmable gain amplifier, with an analog-to-digital converter and a field programmable gate array, to accurately measure beam currents by scaling voltage ranges and adjusting integration times, minimizing analog components and enabling precise comparison of two beam currents using the same analog circuit components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple operational amplifiers are used to measure beam currents, then the measurement capability for multiple beams is improved, but gain and offset errors increase reducing accuracy
Solution Approach 1:
The patent combines multiple beam current measurements into a single analog circuit by time-multiplexing the Faraday cup connections. Instead of using separate operational amplifiers for each beam, the system switches different beam lines to the same integration capacitor and analog-to-digital converter, eliminating multiple amplifiers and their associated errors while maintaining the ability to measure multiple beams sequentially.
Solution Approach 2:
The Faraday cup and analog measurement circuit are designed to serve multiple beam lines universally. The switching mechanism allows the same measurement infrastructure to handle different particle beams by sequentially connecting them to the common integrator, making the system multi-functional without requiring duplicate components for each beam type.
2Adaptability or versatility
If the measurement system is designed to handle a wide range of beam currents, then the adaptability is improved, but the complexity of the system increases
Solution Approach 1:
The system employs dynamic range adjustment through programmable gain amplifiers that can change their gain factor based on the expected beam current magnitude. This allows the same hardware to accurately measure both small and large currents by electronically adjusting the amplification level, avoiding the need for multiple fixed-range measurement channels and reducing overall system complexity.
Solution Approach 2:
The measurement system changes operational parameters such as integration time and amplifier gain to adapt to different beam current ranges. By dynamically adjusting these parameters, the system maintains measurement accuracy across a wide current range without requiring complex hardware modifications for each range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a more accurate and flexible method for measuring beam currents, reducing gain and offset errors, and allowing for precise comparison of two beam currents, enhancing the measurement range and adaptability of the system.
Implementation Method 1
A first charged particle beam is passed into a Faraday cup
Implementation Method 2
an integration capacitor connected between the inverting input and the output of an operational amplifier
Data Source
AI summary
A method and apparatus for measuring the beam current of a particle beam in an accelerator by charging the capacitor across an operational amplifier and controlling the scaling of the amplifier output with a programmable gain amplifier (PGA). The out put of the (PGA) is sampled and storing with an analog-to-digital converter to acquire and store at least two digital voltage values. The two digital voltage values are using to obtain a value proportional to beam current. A field programmable gate array is used to implement digital logic to sample and hold output from the analog-to-digital converter.