Turn-by-Turn Beam Position Measurements at ANKA with LIBERA ELECTRON

Transcription

1 Turn-by-Turn Beam Position Measurements at ANKA with LIBERA ELECTRON E.Huttel, I.Birkel, A.S.Müller, P.Wesolowski About ANKA Test by Frequency Generator Experiences in the Booster Experiences in the Storage Ring

2 ANKA Storage Ring Energy Current Emittance Circumference Optics No. BPM x 40 GeV ma nmrad m DBA

3 Injector MeV Booster Synchrotron 53 MeV Microtron Energy MeV Current 5 ma Emittance 160 nmrad Circumference 26.4 m 70keV e-gun Optics 4 x FoDo No. BPM 8

4 Beam Lines Beam lines in operation (13): LIGA I LGA II LIGA III ABS P-DIFF SUL TOPO INE FLUO SC-DIFF WERA IR I Sf-DIFF Beam lines in construction (3): IR II NANO IMAGE

5 Installed BPM System Analog: multiplexed, demultiplexed Digital: 12 bit ADC, Hz Interface: RS232 BCD: some µm RMS: 1 µm

6 Why LIBERA Electron Look for Turn by Turn Acquisition: Booster: Storage ring: Orbit and Tune at Injection and Ramp Orbit and Tune at Injection, Instabilities

7 LIBERA Electron Parameter Storage Ring Booster f revolution MHz f ADC MHz f rev x f rev x 45 f RF MHz f rev x f rev x 44

8 LIBERA TEST TBT (Signal-Generator) RMS ( µm) larger than LIBERA test results (2-60 µm) What did we wrong? ADC rate should be less: 2096 Due to attenuation: RMS depends on ADC rate!

9 LIBERA TEST SA (Signal Generator) RMS: 0.6 µm RMS: 0.3 µm

10 Injection into the Booster Injection Kick No orbit oscillation from injection due to multi turn injection (averaging) Kick by reduced Extraction Kicker FFT: 256 turns at injection ( )

11 Booster Orbit Kick by Extraction Kicker Horizontal tune dominates vertical FFT 2 x h. tune? Vertical Tune?

12 ANKA Special Booster Revolution Time Decimation (x64) File size 64 k Booster Ramp time Used Storage Ring Parameters: 88 ns 5632 ns 369 ms is less 600 ms 1.54 s Sum Signal Decimated complete Ramp Sum Signal 100 decimated SR turns

13 Used Storage Ring Parameters

14 Orbit during Booster Ramp Before Extraction a bump moves orbit out Bump for extraction is not local Bump is negative opposite to Extraction Bump

15 Injection Line Good: Note: Next step: Got signal in transfer line Got 2 points (separated 368 ns for 70 ns bunch train) Prepare position signal for regulation (MATHLAB)

16 Storage Ring Injection (No RF) Beam Position (Sum Signal) Beam loss after ~8000 turns Energy loss per turn: 1 kev Energy: 500 MeV Energy acceptance: 1.6 % Why is par of the beam lost?

17 Storage Ring Injection Tune (No RF)

18 Storage Ring Injection (No RF) Horizontal Orbit in Dispersive Section Damping of Injection Kick Drift due to energy loss Energy loss: Energy: Dispersion: 1 kev/turn 500 MeV 0.5 m

19 Storage Ring Injection (No RF) Phase Space

20 Storage Ring Injection RF on (100mA)

21 Storage Ring (No RF) ADC Data abs (I(t)+i I(t+90 )) f RF : MHz f adc : MHz f RF -4 x f adc 32.6 MHz f rev : MHz

22 Storage Ring Injection: Septum Bump Slow Bump: Orbit change due to Septum stray field Oscillations due to unclosed Kicker bump

23 Storage Ring Injection: Kicker Bump Oscillations before Optimization Oscillations after Optimization

24 Phase Modulation and Lifetime 2 x Synchrotron Frequency Phase Mod. off Phase Mod. on

25 Phase Modulation and Orbit Phase Modulation off Phase Modulation on 2 x Synchrotron Frequency

26 Kick and Damping Kick with one of the injection kicker (3 µs half sine) Cavity Temperature Current dependent exchange of Excitation and Damping No HOM excited HOM excited Damping time: 11ms (1.3 GeV) 1.5 ms (2.5 GeV)

27 Conclusion Booster: To be done: Got First Turns Got Tunes Got Orbit on Ramp Correct Tune Correct Orbit on Ramp Storage Ring: To be done: Got First Turns Got Tunes Got some Beam Dynamics Optimize Injection Look for fast (Hz) Oscillations Fast Feedback To be done: Learn to use the LIBERA better