The MAX IV transverse
deflecting cavity
IBIC – September 2023
Erik Mansten

Context – connection to previous work
RF driven deflector performance overview

Normalized resolution [fs/(GeV)1/2]

51.2

Fermi@Elettra

25.6
12.8

DESY LOLA

6.4

LCLS LOLA

3.2

MAX IV current

1.6
0.8

MAX IV design

0.4Raiden

PSI C-band

PolariXLCLS X-band

0.2
0.10

Sept 2023

2468
RF frequency [GHz]IBIC ̶ Saskatoon

1012

Motivation – longitudinal dia. @ MAX IV
Femtomax pump-probe results

Soft X-ray Laser at MAX IV1A02-0.4-100Sept 2023

40100
Time [fs]IBIC ̶ Saskatoon

00.4
0-0.4

1B42

Current [kA]

ΔE/E [%]

0.4

0-20 -10 0 10 20
Time [fs][SXL CDR]RF deflectors for longitudinal dia. – kickx

θ𝐸𝐸𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 = 𝑒𝑒𝑒𝑒𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏

RFout

RFin
L𝑉𝑉𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑

Angular deflection: 𝜃𝜃 =Spatial deflection:

Sept 2023

IBIC ̶ Saskatoon

𝑉𝑉𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
sin 𝜔𝜔𝜔𝜔 + 𝜑𝜑
𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏

𝑉𝑉𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
𝑥𝑥 = 𝜃𝜃𝐿𝐿 =𝐿𝐿 sin 𝜔𝜔𝜔𝜔 + 𝜑𝜑
𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏

RF deflectors for longitudinal dia. – streakx

RFout

RFin
L

Spatial deflection
speed:

Sept 2023

IBIC ̶ Saskatoon

𝑉𝑉𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
𝑑𝑑𝑑𝑑
𝐿𝐿𝜔𝜔 cos 𝜔𝜔𝜔𝜔 + 𝜑𝜑 𝑚𝑚/𝑠𝑠=𝑑𝑑𝑑𝑑 𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏

RF deflectors for longitudinal dia. – focusing
x

Quad

RFout

RFin
L

Sept 2023

Beta focus:

𝛽𝛽𝑥𝑥 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 =Focus size:

𝜎𝜎𝑥𝑥 =IBIC ̶ Saskatoon

𝐿𝐿2

𝛽𝛽𝑥𝑥 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑.

𝑚𝑚

𝛽𝛽𝑥𝑥 𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 𝜀𝜀𝑥𝑥 =𝜀𝜀𝑥𝑥

𝛽𝛽𝑥𝑥 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑

𝐿𝐿 𝑚𝑚Temporal resolution
x

Quad

RFout

RFin
LDeflection speed:

𝑉𝑉𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
𝑑𝑑𝑑𝑑
𝐿𝐿𝜔𝜔 𝑚𝑚/𝑠𝑠=
𝑑𝑑𝑑𝑑 𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏(at the zero crossing)𝜎𝜎𝑥𝑥
𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
𝜀𝜀𝑥𝑥
𝑠𝑠
=
Temporal resolution: 𝜎𝜎𝑡𝑡 = 𝑑𝑑𝑑𝑑
𝑉𝑉𝜔𝜔𝛽𝛽
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
𝑥𝑥 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑�𝑑𝑑𝑑𝑑
Sept 2023

IBIC ̶ Saskatoon

Time

Experimental implementation
QuadRFout

Energy*

RFin
L

𝜎𝜎𝑥𝑥
𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
𝜀𝜀𝑥𝑥
𝑠𝑠
=
Temporal resolution: 𝜎𝜎𝑡𝑡 = 𝑑𝑑𝑑𝑑
𝑉𝑉𝜔𝜔𝛽𝛽
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑
𝑥𝑥 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑�𝑑𝑑𝑑𝑑

*Requires a spectrometer dipole

Sept 2023

IBIC ̶ Saskatoon

ESS

Introduction – MAX IV facility
3 GeV storage ring

1.5 GeV storage ringElectron guns

Short Pulse facility
BeamlinesBeamlines

Office building• Two storage rings• 15 beamlines• Full energy injection• Top-up• Short Pulse Facility• Femtomax beamline
Sept 2023

IBIC ̶ Saskatoon

The MAX IV linear accelerator

probepumpCompression and linearization

Photo cathodeRF gun

BC1 @ 260 MeV

EΔEE0

ΔE

φΔt

BC2 @ 3 GeV

E0 ∆E 
 ∆E 
∆z = R56 
 + T566 
 E  E tΔt2SPF

Arc and chicane type compressors
EΔE

𝑅𝑅56 < 0E0ΔEChicane type bunch compression• R56<0• Pre crest acceleration• T566>0• Linearize with harmonic cavity• Harmonic non-linearized tuning

E0tφΔtΔt

𝑅𝑅56 > 0EΔEE0ΔEφΔt

𝑇𝑇566 > 0E0tΔt

 ∆E  ∆E 
∆z = R56 
 + T566 
EE




2Arc type bunch compressor• R56>0• Post crest acceleration• T566>0• Magnetic linearization• Magnetic non-linear tuningPhoto cathodeRF gunLinearization tuning

Sextupole tuning

BC1 @ 260 MeV

EΔEE0ΔE

φΔt

BC2 @ 3 GeVE0SPF

 ∆E  ∆E 
∆z = R56 
 + T566 EE




t

2Δt

Arc type bunch compressor• R56>0• Post crest acceleration• T566>0• Magnetic linearization• Magnetic non-linear tuning

Compression tuning

Photo cathodeRF gun

BC1 @ 260 MeV

EE0ΔE

φ

BC2 @ 3 GeV

E0SPF ∆E 
 ∆E 
∆z = R56 
 + T566 
EE




t

2ΔtΔt

Arc type bunch compressor• R56>0• Post crest acceleration• T566>0• Magnetic linearization• Magnetic non-linear tuning

MAX IV TDC setup

30m

Femtomax
Linac

TDC setup

Beta [m]30002000• 1 fs resolution target• S-band (3 GHz)
• 100 MV integrated field1000• Long setup• Spectrometer dipole

𝑉𝑉𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
𝜀𝜀𝑥𝑥
𝜎𝜎𝑡𝑡 =𝑠𝑠𝑉𝑉𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑 𝜔𝜔 𝛽𝛽𝑥𝑥 𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑

RF design•

Scandinova K2 modulator•

SLED RF pulse compressor•

2 x 3m structures•

Switchable polarization(phase II)David Olsson

Installation

Installation

Installation

Installation

Beam commissioning results• Temporal resolution measurement• Compression scans• Linearization scans

September 2023

IBIC Saskatoon

Beam centroid pos. [mm]Temporal resolution𝑑𝑑𝑑𝑑= 8 𝑚𝑚𝑚𝑚�𝑝𝑝𝑝𝑝𝑑𝑑𝑑𝑑𝜎𝜎𝑡𝑡 =𝜎𝜎𝑥𝑥 = 24 𝜇𝜇𝑚𝑚

𝜎𝜎𝑥𝑥
𝑑𝑑𝑑𝑑�
𝑑𝑑𝑑𝑑= 3 𝑓𝑓𝑓𝑓

TDC phase delay [ps]Johan Lundquist
September 2023

IBIC Saskatoon

Compression scanEEE

Johan Lundquist
September 2023

IBIC Saskatoon

Compression scan

Johan Lundquist
September 2023

IBIC Saskatoon

Linearization scan
EE

0.4

0.4

0.2

0.2

0.2

0-0.2
-0.4

-0.1

0t [ps]

September 2023

0.1

ΔE/E [%]

0.4

ΔE/E [%]

ΔE/E [%]

E0-0.2-0.4-0.1

0t [ps]0.1

IBIC Saskatoon

0-0.2-0.4-0.10t [ps]0.1Linearization scan
Quadratic component
0.12

d2t/dE2 [ps2]

0.08
0.04
0-0.04
-0.08
3.5

4

4.5
5
Sextupole k2 value [m-2]5.5

6Johan Lundquist
September 2023

IBIC Saskatoon• 3 fs< 1 fs• Current streak 8 mm/ps• Target 30 mm/ps• Increase RF power• Bakout• SLED tuning

Beam centroid pos. [mm]TDC challenges and outlook

TDC phase delay [ps]• Current unstreaked beam focus 55 μm (FWHM)• Target below 30 μm• Slice Twiss parameter scans• Phase shifter to turn polarization
September 2023

𝑑𝑑𝑑𝑑
= 8 𝑚𝑚𝑚𝑚�𝑝𝑝𝑝𝑝
𝑑𝑑𝑑𝑑

IBIC Saskatoon