1. PETRA III. Machine development Satellite bunch clearing
Rainer Wanzenberg
DESY MPE -
for the PETRA III team
Three Way Meeting, DESY, Hamburg
Sep 15, 2016 1

2. The DESY site in 2016 Extension Hall East Extension Hall North
LINAC II  PIA  DESY II  PETRA III
C = 29 m, E =450 MeV C = 293 m, E = 6 GeV C = 2304 m, E = 6 GeV
Extension Hall East
Max von Laue Hall
Extension Hall North

3. PETRA III Implementation of the PETRA III extension:
Parameter
PETRA III
Energy / GeV 6
Circumference /m
2304
Emittance (horz. / vert.) /nm
1.2 /
Total current / mA
100
Number of bunches
960 40
Bunch population / 1010
0.5 12
Bunch separation / ns 8
192
Damping Wigglers: B ~ 1.5 T, l = 0.2 m
2 x 10 x 4 m = 80 m, ex: 5 nm  1.2 nm
Implementation of the
PETRA III extension:
Feb 2014 – Feb 2015,
Two New Halls PXN, PXE

4. New beam lines: Tentative time line
First beam
P65
X-ray absorption spectroscopy
Oct. 2015
P64
Spring 2016
P24
Chemical crystallography
2Q 2017
P21
High-energy X-ray materials science
P22
Nano X-ray spectroscopy
P23
Nano X-ray diffraction
P66
Time-resolved luminescence spectroscopy
t.b.d.
P61
High-energy X-ray eng. mat. sci. (HZG) LVP extreme conditions (DESY)
2018
P62
Small-angle X-ray scattering
>2018
P63
t.b.c.
-----
P25
t.b.c
Phase 1
Phase 2
Phase 3 4 4 4 4

5. PETRA III Extension North
New Beam lines P64 and P65
Tue , first photon beams from PU64
and PU65, 1 mA run
P 65
First experiments in Oct. 2015
scheduled user from June 2016
P 64
First experiments in May 2016
after a problem with the monochromater was solved

6. Beam line Set Up P 64 / P 65 (April, 2016)
Large fringe field from the PDE dipole
compensation for the horizontal kick
small residual vert. kick
compromise for the photon beams
PU64
PDE Dipole
20 mrad
PDE dipole:
New coil configuration has been ordered
installation is planned for the 2016/17
winter shut down
kick compensation:
A correction coil of the dipole is set according to the undulator gap
P65

7. Satellite bunches
Timing mode with 40 Bunches, some experiments need a very good bunch purity (~ 10-9 … 10-8 )
But there are satellite bunches
generated in PETRA (2 ns and 4 ns)
from the injector chain (125 MHz in PIA)
Studies started Aug. 2015:
satellite bunch clearing
using the Multibunch
feed back system
Ref.:
Longt. bunch structure in the Photon Factory
T. Obina et al. NIM A 354 (1995)
Bunch Purity Measurements at PETRA III
J. Keil et al. IPAC 2016
Measurement at beam line P01, July 31, :45 h

8. Satellite bunch clearing
Measurement after clearing and 1 h later
In timing mode: X-ray pulses with 90ps width and 192ns separation for pump probe & nuclear resonant
scattering (NRS) measurements.
Suppression down to 10-8 is required
MBFB, vert. excitation of the
satellite bunches
Bunch clearing in 2015
proof of principle
satellite bunches can be cleared
using the multibunch feedback
measurement of the sattelite bunches
in close collaboration with beam line P01
procedure and claering parameters
not yet optimized

9. → powerful broadband feedback neccessary
Multi bunch feedback
Coupled bunch instabilities in PETRA:
longitudinal
horizontal
vertical
Ithres (mA) 7 6
1/t (Hz) 35 50 60
Zeff
3.6 MΩ
45 MΩ/m
54 MΩ/m
PETRA III: 12 seven cell cavities which large par. shunt impedance
→ powerful broadband feedback neccessary
Required damping 1/t:
Longt Hz or ms
Horz Hz;
Vert Hz or ms
Bandwidth 62.5 MHz
(8 ns bunch spacing)
Sattelite bunch clearing:
Intensity dependent tune shift:
~ 1.6 kHz / mA (vert. Plane)
40 Bunche mode: 2.5 mA bunch current
vert. Feedback can excite the low intensity
sattelite bunches at their betatron tune
J. Klute, K. Balewski et al., DIPAC’11, TUPD81

10. Sattelite bunches: automatic clearing procedure (2016)
satellite bunches measured at beam line P01
generated in PETRA (2 ns and 4 ns)
from the injector chain (125 MHz in PIA)
User Run 2016:
satellite bunch clearing using the Multibunch
feed back system,
automatic procedure at every n-th
top up injection (n = 1, n =100)
– 8ns
8 ns
red 8 ns, blue – 8ns
Timing mode with
40 Bunches, some
experiments need a
very good bunch purity
(~ 10-9… 10-8)
measurement cycle
~ 15 min
10-8

11. Clearing procedure: impact on beam line signals
Signal from beam line P10 (counts per second)
drop by ~ 25 % is not acceptable for some
experiments.
further optimization with reduced kick amplitude
and sweep range (tune frequency range)
User Run 2016:
successful satellite bunch clearing
using the multi bunch feed back system
with neglectable impact for the beam lines
automatic procedure at every top up injection
was development in close collaboration
with
the beam lines *), the feedback group, the software
group, the Preaccelerators (DESY II, Linac, Pia)
zoom
signal
current
*) Beam line P01: O. Leupold, H.-C. Wille

12. Emittance Diagnostics
North: interferometric measurement
dipole radiation
(originally set up for a bunch
length measurement)
Von Laue Hall:
Diagnostic Beam Line
South East: new diagnostic station

13. Emittance Diagnostics in SE
South East: new diagnostic station

14. PETRA III: Beamlines in hall East – Further plans
P 22 Nano spectroscopy
P 21 High-energy X-ray materials science
P 23 Nano diffraction
P 24 Chemical crystallography
Front end components for the photon beam lines P 22, 23, 24 have been installed in the East hall during the last shut down 2015/16.
Welche Beamlines sind das?
Flaggen reinpacken, international: Schwedisch, Indisch, Russisch
Beginn Nutzerbetrieb: P64 war sogar schon

15. Tentative schedule and plans 2017
Shut down 2017 Jan / Feb / March
installation of a chicane in the straight section east
preparation for the installation of an In Vacuum Undulator
survey / realignment of the accelerator components
installation of the undulators PU 22, 23 and 24
new coil configuration for PDE magnets
Shut down July / Aug
installation of an new absorber in the wiggler section North
2017: installation of a chicane,
and front end components
front end components installed in 2015/16
2017: installation of undulators,
realignment of accelerator components
2017 July: new absorber + front end
components
installed in 2015

16. In-vacuum undulators Two in-vacuum undulators
PETRA III: 14 Beamlines in the Max von Laue Hall
Two in-vacuum undulators
(One undulator for P21)
have been ordered
delivery of the first undulator
is scheduled for 2017
Number
ID Type
Energy range (keV)
Cell
P01
10 m U32 (2 x 5 m)
5 – 40
P02
2 m U23
20 – 100 1
P03
2 m U29
8 – 25
P04
4 m U65 (APPLE)
0.2 – 3.0 2
P05
8 – 50 3
P06
2 m U32
2.4 – 50
P07 (option
low beta)
4 m U19 (IV)
(pres. 2m)
50 – 300 4
P08
5.4 – 30 5
P09
P10
5 m U29
4 – 25 6
P11
8 – 35 7
P12
4 - 20
P13
5 – 35 8
P14
5 - 35
another one is foreseen for P07
High bx
Low bx
High beta: bx = 20 m by = 4 m
Low beta : bx = 1.4 m by = 4 m
Max von Laue Hall: 14 beam lines
8 DBA cells ( length 23 m)

17. Thank you for your attention !