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

2. The Australian Synchrotron
3 GeV
100 MeV

3. The Storage Ring
720 ns

4. 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

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

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

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

8. 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

9. MSM Photodiode

10. 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

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

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

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

15. 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”

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

17. 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.

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