Beam Position Monitor for a Particle Accelerator Andrew Noble Mona - - PowerPoint PPT Presentation

Beam Position Monitor for a Particle Accelerator

Andrew Noble Mona Elkady

Overview

• Free Electron Lasers and Particle Accelerators
• Beam Position Monitors
• Pulse Generator
• Sample and Hold Circuit
• PCB Design

FELs and Particle Accelerators

• Particle Accelerators

○ Use strong electric fields to accelerate a beam of particles to relativistic speeds

• Free Electron Laser (FEL)

○ Uses electron beam created by particle accelerator to create tunable electromagnetic radiation

source:http://www.lightsources.org/what-free-electron- laser

Beam Position Monitors (BPM)

Beam Position Monitors

• Measure the location of the electron beam within the accelerator

tube

• Ensure the functioning of the particle accelerator by centering the

beam through the use of corrector magnets What are we doing differently?

Source:http://durpdg.dur.ac.uk/vvc/accelerators/bpm.html

Sample and Hold

Sample and Hold Circuits

• Samples data
• Holds that data until it can be processed

Source:http://en.wikipedia.org/wiki/Sample_and_hold#mediaviewer/File:Sample-hold-circuit.svg

Sample and Hold Requirements

• Needs to have a high open loop gain

○ We are trying to measure the beam position on the order of tens of micrometers which means we need at least 10,000 V/V open loop gain

• Needs a high enough bandwidth

○ The pulses that can be measured in a particle accelerator can have a pulse width on the order of picoseconds (extremely fast) ○ It isn’t reasonable to design a sample and hold with a bandwidth that large ○ We will be implementing a pulse stretcher to reduce the bandwidth requirements

Pulse Generator

Last year’s schematic Analyzed:

• MOSFET vs. BJT
• DC Converter vs. Boost Converter

Final Pulse Generator Schematic

Changes to last year’s

• schematic. The change in the

converter allows for a range of 10-14V input and 55 to 135 V

• utput.

Final Pulse Generator Circuit

Final circuit Wiring on back of circuit Result of circuit

PCB Design

Goal: To create a PCB of our pulse generator to have a solid prototype with no loose ends. Constraints

• Size
• Cost
• Accuracy of custom parts

PCB Process: Schematic

PCB Process: Footprints

PCB footprint before changing some of the parts and rearranging everything around.

PCB Footprints After Changes

Budget

Purchased Items Description Cost ($) Quantity Part Number

Sample and Hold Op- Amp 39.57 1 AD585AQ Total Cost = $ 39.57

Conclusion

While there is still some work to be done to complete the design, such as settling on a final sample and hold design, implementing an A/D converter, and creating the code to display the sampled information; we are currently

• n track for designing a low cost single channel BPM for implementation on

particle accelerators. Are there any questions?

References

• Max VanKeuren and Stephen Watras. (2014) Beam Position Monitor for CSU Accelerator Laboratory. Retrieved from http:

//projects-web.engr.colostate.edu/ece-sr-design/AY13/beam/Documents/FinalReport.pdf