Bunch Profiling with a Rotating Mask Mitchell Miller with Dr. Alan Fisher

Synchrotron Light Acceleration of charged particles = radiation As V  C the radiation becomes focused Using a strong B field forces electrons to orbit Synchrotrons are a large ring of uniform B Beams generated are used for nearly infinite applications

LHC LHC is a proton collider, not synchrotron Greater mass = less synchrotron radiation Collisions require careful beam alignment Order of microns compared to kilometers in circumference Previous bunch measurement techniques involved: High speed camera Long time Frequent replacement from radiation damage

Solution: Rotating Mask Wheel with four groups of three slots Each group has slot at 0°,45°, and 90° Slots provide line integration points PMT will detect light that passes through slot In one ring turn slot has shifted slightly providing a new point with every ring turn Combining every point will give a Gaussian profile Each bunch will have a unique profile

Slot Positions

Profile Creation Each bunch provides a peak Peaks are chosen using software that indexes each bunch Output from motor is recorded, giving position of wheel One bunch measured for this experiment “Timing Bunch”

Profile Results

Fitting to Obtain Beam Size Beam sigma = 234.75 µm Expect sigma = 60.91 µm

Error Diffraction effects Precise focus PMT charging effects Sampling and data access

Conclusion Benefits Drawbacks Deployment at LHC Fast Radiation resistant Simple Drawbacks Error from diffraction (possibly from sampling rate) Deployment at LHC

Thank You Questions