The Fill Pattern Monitor For the Australian Synchrotron David Peake Supervisors: Dr Roger Rassool Dr Mark Boland

The Australian Synchrotron 3 GeV 100 MeV

The Storage Ring 720 ns

Aims of This Project Quantify beam characteristics Optimize injection parameters to: increase the maximum stored current increase the lifetime of the beam Lower the frequency of re-injection

Initial Beam Profile Injected current is not evenly spread Current example of beam profile: 720 ns

An Ideal Beam Profile Stored current is spread evenly across the entire period 35 ps 720 ns 2 ns

û ü û ü Measurement Methods Directly measure the electrons in the ring Measure the synchrotron light X-rays Visible Light ü û ü

The Requirements A photodiode with a super fast rise time A digitiser with a rapid sampling rate In our device the key component will be a high speed MSM photodiode

MSM Photodiode

ü ü ü Experimental Setup Fill Pattern Monitor (FPM) DC-30 GHz 14 GHz Bending Magnet 1 Electron beam X-rays (Not to Scale) Optical Chicane Fill Pattern Monitor (FPM) MSM AMP DIG Visible Light ü ü ü DC-30 GHz 14 GHz 8 GS/s

Results Tuesday 17th of October – 12:15 am A single bunch was measured

How do we know? Need to validate the results against well used diagnostic devices

Injection Delay Placed a delay into the injection timing, and injected from the booster ring.

Australian Synchrotron Milestone Two days later, the FPM was used to achieve the following major milestone… A maximum current of 100 mA A beam lifetime of 12 hours (a 50% increase) “Couldn’t get the smiles off their faces”

Continuous Top Up Mode The Australian Synchrotron is now capable of running in continuous top up mode This is a world first

Summary Able to digitise a single 35 ps light pulse Can measure the beam profile in real time Information from the FPM has already resulted in a higher maximum current and a 50% increase in beam lifetime.

Acknowledgements Dr Roger Rassool Dr Mark Boland The Accelerator Group at the Australian Synchrotron.