Development of the 40 GHz Bunch Arrival Time Monitor Pickup · Nils Mildner Antonio des Zubiaurre Wagner Jens Tiessen ! MSK (Beam control) Christopher Gerth Holger Schlarb Martin

Development of the 40 GHz Bunch Arrival Time Monitor Pickup

Dr.-Ing. Michael Bousonville DESY, MDI techn. Forum, 27.09.2013

Dr.-Ing. Michael Bousonville | Development of the 40 GHz BAM Pickup | 27.09.2013 | Page 2

>  Introduction §  Person involved

§  Measurement Principle

>  Goal

>  Status 2010 – 10 GHz BAM-Pickup

>  40 GHz BAM-Pickup §  New Design

§  Manufacturing

>  Cabling §  New Requirements

>  Signal Measurement §  Deviations

>  Results

>  Outlook

Overview


>  Funding: BMBF §  Weiterentwicklung eines Ankunftszeitmonitors, TU Darmstadt §  Ultrakurze Elektronenpakete bei FLASH, Universität Hamburg und DESY

>  Time frame: §  1 September 2010 to §  28 February 2012

>  Project leader from mid 2011 on: Michael Bousonville

Basic Condition


>  TU Darmstadt §  IMP (Institut für Mikrowellentechnik und Photonik)

Andreas Penirschke Aleksandar Penirschke

§  GSC (Graduate School of Computational Engineering) Alexander Kuhl Sascha Schnepp

>  Uni Hamburg Juliane Roensch-Schulenburg

>  DESY §  MDI (Diagnostic Group)

Silke Vilcins-Czvitkovits Jürgen Kruse Anke Ziegler Maike Siemens Holger Sokolinski

§  MVS (Vacuum Group)

Nils Mildner Antonio des Zubiaurre Wagner Jens Tiessen

§  MSK (Beam control) Christopher Gerth Holger Schlarb Martin Schäfer Marie Kirstin Czwalinna Cezary Sydlo Michael Bousonville

§  ZM

Josef Gonschior

Person Involved


Measurement Principle

Courtesy of Marie Kristin Czwalinna

Accuracy = f (slope)

Slope = f (bandwidth)


>  Current BAM design: bandwidth limited by 10 GHz

>  Goal for new BAM design: bandwidth ≈ 40 GHz

>  Purpose: detection of bunches with lower charges

Goal


10 GHz BAM-Pickup – Design

Alexander Kuhl, TU Darmstadt.

>  Status 2010


>  Signal of a Single BAM-Feedthrough (simulation) §  Standard Bunch:

Charge = 20 pC Length = 2.35 mm Gaussian shaped

§  Slope = 71 mV/ps

§  Ringing = 62 %

10 GHz BAM-Pickup – Performance

Alexander Kuhl, TU Darmstadt.


=> measurement resolution ↓

10 GHz BAM-Pickup – Measurement Resolution

>  measurement resolution = f (slope of pickup signal)

>  slope = f (bunch charge)

>  slope = f (bandwidth of pickup)

bandwidth ↑

bunch charge ↑

Measurement resolution vs. bunch charge (measured by M. Bock)

0

10

20

30

40

50

0 0.2 0.4 0.6 0.8 1

Mea

sure

men

t Res

olut

ion

[fs]

Bunch Charge [nC]

Higher bandwidth improves measurement resolution specially for low charged bunches


>  Slope ↑

>  Ringing ↓

>  Boundary Condition: Keep peak voltage at 1.5 V

Bandwidth ↑ => Slope ↑ => Measurement Resolution ↓

Reflections in pickup ↓ => Ringing ↓

Parameters to improve


>  Pickup Design by TU Darmstadt

New Design – 40 GHz BAM Pickup

=> Low reflections

40 GHz waveguide


>  Pickup Design by TU Darmstadt


Angelovski et al., TU Darmstadt, IPAC 2011



>  Improvement of performance (simulated)

old

new


>  No vacuum suitable Prototype




>  Verification of simulations with s-parameter measurement



Measured values of the prototype correspond to the simulated.


>  Tolerance study for manufacturing §  Result: Tolerances for critical RF component parts

± 0.02 mm and ± 0.5° => Deviation:

→ Slope < 2 % → Ringing < 2 %


Aleander Kuhl et al. IPAC2011


The Problem

>  Build in the Anritsu Feed Through §  Fit in the cylinder vacuum-tight – this means 10-10 mbar*l/s

§  Mounting the cone

Glass bead


The Problem

>  Very small dimensions of §  Glass bead and

§  Cone



The Problem

>  Laser welding test §  Company Escotec

§  Welding process damages the glass (hairline cracks) => no longer vacuum tight

Courtesy of Silke Vilcins


The Problem

>  Further attempts to fit in the glass bead §  Laser welding by company Lasertec → failed

§  Hard-soldering eutectic (780°C) → failed: 10-5 mbar*l/s

§  E-beam welding → not promising

§  Soft-soldering → in general not suited for vacuum applications at DESY, because of flux material,

§  but there is a special soft solder that works without flux material → no success until know


The Surprise

>  Jens Tiessen suppose such a form will be good for welding

>  I ask Orient Microwave and they say that’s possible

>  Silke Vilcins: they should manufacture the complete feedthrough


>  In the end we asked 2 companies to build up the complete feedthroughs §  Orient Microwave

§  Times Microwave

>  S. Vilcins said this increase our chance to get one which really works. We know from experience that it would not be easy.

>  Orient Microwave claim they can do it almost exactly according to our plans

>  Times Microwave can do it with some modifications

>  We found our last design failure – K connector jut out not long enough

Manufacturing of the Pickup


>  Times Microwave - Version X5 §  Slope: 71 mV/ps → 400 mV/ps → 566 mV/ps

§  Ringing: 62 % → 5 % → 6.8 %

§  Theoretical improvement of measurement resolution by factor 8, but ringing slightly higher


The modification of the original design has an effect.

Correction for K connector


>  Costs (Times Microwave) §  Initial fee: 5,865 $

§  Pickup for 4 pieces: 1,120 $/each

§  Pickup for 40 pieces: 810 $/each

§  Pickup for 100 pieces: 630 $/each

>  For prototype = 5,865 + 8 x 1,120 = 14,825 $ ≈ 11 k€

=> 2 complete BAMs, if all ok

Ordered October 2011

engineer drawings (Rev. A) approved (complicate 5 iterations)

Promised delivery time 12 to 14 weeks

One year later we set an ultimatum

4 December 2012 we canceled the purchase



>  Orient Microwave §  Slope: 71 mV/ps → 400 mV/ps → 428 mV/ps

§  Ringing: 62 % → 5 % → 4.85 %

§  Theoretical improvement of measurement resolution by factor 6


The deviation from the original design (hole in the cone) has no effect.


>  Orient Microwave §  Last modification – K connector fits now


→


>  Costs (Orient Microwave) §  Initial fee: 5,300 €

§  Pickup for 4-8 pieces: 2,970 €/each

§  Pickup for 40 pieces: 735 €/each

§  Pickup for 100 pieces: 590 €/each

>  For prototype = 5,300 + 8 x 2,970 = 29 k€

=> 2 complete BAMs, if all ok

Ordered October 2011, Engineer drawings approved, Delivered March 2012

Vacuum test by MDI ok

S parameter measurements ok

Approved for XFEL by MVS – February 2013



>  Orient Microwave delivered feedthrough


Courtesy of Jürgen Kruse


>  Complete Pickup, housing by MDI



Lessons learned

>  The realization of a new pickup design needs a lot of time

>  We had to contact earlier manufacturing companies

>  It is very important to check the manufacturing drawings of the companies very carefully – we found more than one critical mistake


Cabling – New cable requirements

>  40 GHz

>  Low delay drift

>  Special requirements for installation in FELs §  Halogen free (causes toxic gases if it burns)

§  No PTFE (Teflon)

§  Radiation resistant (> 10,000 Gray)

§  Flame-retardant (Brandklasse B oder C)


Cabling – SiO2 Times Microwave

>  TCD ≈ 25 fs/m/K @ 20°C

>  α = 2.8 dB/m @ 36 GHz or α = 3.9 dB/m @ 38 GHz

>  Cut off frequency = 36 GHz or Cut off frequency = 65 GHz

>  EMI Shielding > 110 dB

>  No PTFE (Teflon), but SiO2 => Radiation resistant ( > 10,000 Gray)

>  Phase matching < 4.6 ps

>  Semi rigid


Cabling – Why we not use the old BAM Cabling?

BAM Pickup

Combiner ATM P213H 1 to 18 GHz

SMA Combiner

ATM P213H 1 to 18 GHz

SMA

SM

A S

MA

SMA SMA

SM

A S

MA

Semi rigid (outer diameter = 3.58 mm) Suhner Y5 (UT-141A) or Radiall C 291 860 066

Konfektioniert, flexibel: Pastanack PE 3481 LF (Cable type: PE-SR402FL) Wird auf die passende Länge durch eine Kombination vom kurzen Kabelstücken gebracht.

SMA

SMA Limiter

Agilent N9356C, 25 dBm

Pastanack PE 3481 LF, L = 20 cm

Electro Optical Modulator Covega Mach-10 081

SMA

SMA Attenuator

Minicircuits BW-S15W2+ 10 to 20 dB

Electro Optical Modulator Covega Mach-10 081

SMA feed through SMA feed through

BAM-Box

SMA right angle plugs on all UHV feed throughs

SMA right angle plugs on the modulator

Right angle plugs => 10 GHz difficult 40 GHz big reflections

Bandwidth < 18 GHz

Bandwidth < 18 GHz PTFE (Teflon) inside TCD ≈ 1 ps/m/K


Cabling – Supposed by TU Darmstadt

ATM P213H 1 to 18 GHz

PS2-55-450/17S Pulsar Microwave 40 GHz

50 GHz


Cabling – Phase matching of the combined signals

>  Cables between pickup and combiner have to be matched

>  Length of relevant slope ca. 10 ps

>  Phase matching < 4.6 ps specified for SiO2 cables

>  Cables have to be bended ones => delay shift

>  After bending they have to be fixed => no more delay shift

=> Best type: semi-rigid

10 ps


Cabling – Fixing Concept

Metal plate


Cabling – Fixing Concept

>  Design by Josef Gonschior (ZM)

>  Improved by Anke Ziegler und Holger Sokolinski (MDI)


Cabling – Bending Concept

>  Bending each cable equal to get an equal delay shift

>  Designed by Josef Gonschior (ZM)

>  Manufactured by Uni HH Workshop

>  Rolls improved by Martin Schäfer

>  Checked by Thomas Weber elspec


Cabling – Bending Concept

>  Bended cable

>  Delay difference due to bending for the first lot of 8 pieces §  Mean = 3.5 ps

§  Standard Deviation = 0.7 ps


Cabling – Matching Results

>  Considering measurement accuracy §  Network analyzer Rohde und Schwarz ZVK 40 GHz

§  2° @ 36 GHz = 154 fs

§  => Maximum measurement error comparing both branches = 2 * 154 fs = 308 fs = limit

>  Matching for the last 3 cable sets including combiner (40 GHz branch) §  Measured < 300 fs

§  Guarantied < 608 fs (including maximum error)


First Installation

>  FLASH

>  SFELC

>  Position 185 m


First Installation – Details

>  FLASH – SFELC, Position 185 m


Cabling – Attenuation

>  Choosing the cable we have a looked at the attenuation

>  SiO2 cable type had been chosen, because it’s the only one that combines §  40 GHz transmission and

§  radiation resistance

>  But in general: fcutoff é => cable diameter ê => attenuation é


Cabling – Attenuation

>  Therefore I ask the coworkers form TU Darmstadt to calculate the slope reduction

>  Based on this we chose the 3.58 mm cable with fcutoff = 36 GHz which is below our original goal, in order to get more slope

>  In the mean time it turns out that it was difficult to get Mach-Zehnder-Modulators with 40 GHz bandwidth

Internal Documentation:Development of a new 40 GHz Pickup Aleksandar Angelovski, Aleksander Kuhl, Andreas Penirschke, Sascha Schnepp


Signal Measurement

>  Measurement with a scope at 16 pC by C. Sydlo

Fit mit:

Slope = 71.4 +- 5 mV/ps Amplitude = 0.435 +- 0.02 V (null-peak) Ringing >> 5 %


Slope [mV/ps] Upp [V] Ringing [%]

Measurement @ 16 pC: 71.4 0.87

Scaled up to 20 pC: 89.3 1.09 >> 5

Expected something about: 264 3.22 5

Question: Why it deviates so much?

Signal Measurement


Signal Measurement – Verification

>  Looking for deviations in our models §  Feedthroughs are 0.5 mm off in radial positions

§  Diameter of beam pipe varies in upstream direction

§  Different cable type used, but with similar attenuation

§  Cable are a bit longer

>  Redo simulations (Alexander Kuhl)


Pickupeinschub sitzt bündig Slope: 504 mV/ps Amplitude: 4.02 V (peak peak) Ringing: 4.51 %

Mit Rohrinnenradius 34 mm (FLASH-Body) (ohne Strahrohr vorab)

Pickupeinschub sitzt 0.5 mm zu weit aussen Slope: 474 mV/ps Amplitude: 3.74 V (peak peak) Ringing: 7.34 %

Signal Measurement – Verification: Radial Displacement


Slope: 416 mV/ps

Pickupeinschub sitzt bündig Slope: 504 mV/ps Amplitude: 4.02 V (peak peak) Ringing: 4.51 %

Mit Rohrinnenradius 34 mm (FLASH-Body) (ohne Strahrohr vorab)

Pickupeinschub sitzt 0.5 mm zu weit aussen Slope: 474 mV/ps Amplitude: 3.74 V (peak peak) Ringing: 7.34 %

Signal Measurement – Verification: Radial Displacement


Rohrsprung: ovale Öffnung + Zwischenflansch

Vergleichssimulation

Signal Measurement – Verification: Beam Pipe Variation


>  Zwischen BAM und SFLASH Undulator 45 cm Rohr

>  Ovale Öffnung: 7.7 cm x 15 cm + runder Zwischenflansch 8 cm Durchmesser

Vergleichssimulation Mit Rohrsprung Slope: 475.4 mV/ps 473.3 mV/ps Amplitude: 3.38 V (peak peak) 3.32 V (peak peak) Ringing: 7.5 % 19.1 %

Signal Measurement – Verification: Beam Pipe Variation


Signal Measurement – Verification: Attenuation

>  Transmission §  Anritsu Cable 370 mm

§  Combiner

§  Anritsu Cable 2500 mm

Mit Rohrsprung Mit Transmissionsdämpfung Slope: 473.3 mV/ps 118.3 mV/ps Amplitude: 3.32 V (peak-peak) 1.36 V (peak-peak) Ringing: 19.1 %


Vergleich simuliertes Signal (blau) und gemessenes Signal (rot)

Signal Measurement – Simulation


Vergleich simuliertes Signal (blau) und gemessenes Signal (rot)

Signal Measurement – Simulation


Effekt Betrachtungspunkt Slope [mV/ps]

Reduktion Amplitude peak peak [V]

Reduktion Ringing

1 FLASH-Body d.h. 34 mm Innendurchmesser Radiale Position korrekt

Am Ausgang einer Durchführung

504.0 4.02 4,51%

2 Durchführungen 0,5 mm zu weit außen

Am Ausgang einer Durchführung

474.0 -6 % 3.74 -7 % 7,34 %

3 Mit Rohrsprung 45 cm vorher Am Ausgang einer Durchführung

473.3 -6.1% 3.32 -17.4 % 19.1 %

4 Transmission Am Ende des Kabels 118.3 -76.5 %

1.36 -66.2 %

Messung auf 20 pC hochskaliert

Am Ende des Kabels 89.3 1.09

Abweichung Simulation - Messung

Am Ende des Kabels 24.5 % 19.9 %

Signal Measurement – Simulation, Overview


>  Größe der Abweichung Simulation & Messung §  Slope = 24.5 %

§  Amplitude = 19.9 % im üblichen Rahmen

§  Gute Übereinstimmung beim Signalverlauf

§  Die Ursprüngliche Simulation mit einem Slope = 264 mV/ps scheint nicht zu stimmen

>  Gründe für Abweichungen §  Simulation:

Vereinfachungen und bei großen Modellen ungenauere Gitter

§  Messung:

a) Timingjitter durch Trigger und Scope selbst. Triggern war schwierig. b) Jeder Punkt wird durch ein neuen Bunch erzeugt -> Bunch Timingjitter

Signal Measurement – Deviation


Signal Measurement – Valuation

>  Bewertung der Messung §  Durch die geänderten Rahmenbedingungen

a) Größere Signaldämpfung: Andere und länger HF-Kabel (Anritsu K118) b) Sprung im Strahlrohr c) Durchführungen nicht etwas zu weit außen

§  Hat sich die Signalform deutlich verändert

a) Reduktion: Slope und Amplitude b) Vergrößerung des Ringings

§  Berücksichtigt man die geänderten Rahmenbedingungen in der Simulation, bekommt man ein ähnliches Ergebnis.

=> die Übereinstimmung zwischen Simulation und Messung ist so gut, dass davon auszugehen ist, das die Durchführungen von Orient Microwave entsprechend ihrem Design verhalten.

=> Die Tests sind mit positivem Ergebnis abgeschlossen worden.

=> Das Pickup-Design konnte planmäßig realisiert werden.

=> Die Pickups für FLASH können gefertigt werden.


Signal Measurement – Recommendations

>  Verkabelung §  SiO2-Kabel verwenden

§  Kurze Kabelwege, wenn möglich

=> Mehr Slope

>  Sprünge im Strahlrohr von klein auf groß §  Vermeiden

§  Wenn es nicht vermeidbar ist, dann Taper einsetzen

=> Weniger Ringing

>  Durchführungen plan in den BAM-Body einbauen §  Versatz nach Außen kann in Zukunft vermieden werden

=> Weniger Ringing


Results

>  First functional 40 GHz BAM pickup §  To our knowledge no one else has ever produced a feedthrough with 40 GHz

bandwidth

>  Other institutes have ordered some feedthroughs by us §  PSI: 10 already delivered, installation in November, measurements in February 2014

§  HZDR: 14 delivery in progress, installation in October, measurements in November

§  KIT: 8

>  Licensing §  Semic RF Electronic GmbH ask for a license for the feedthrough

§  They are the distributor for Orient Microwave

§  Negotiations with Uni Hamburg and TU Darmstadt are ongoing (Ilka Mahns TT)

>  Physical Review Paper


Outlook

>  The 40 GHz BAM frontend has to be realized §  Unforeseen problems with the first tested 40 GHz modulator

§  Ultimately the measurement accuracy of the BAM can only verified with a appropriate frontend

>  Idea came up to use other RF cables §  Intention lower the attenuation

§  Phase Master 160 is considered

- loss reduction maximum 1 dB => 12 % more slope and amplitude

- radiation resistance is unclear

§  Elspec want to test the radiation resistance at Fraunhofer Institut Euskirchen

>  New BMBF Antrag §  To tackle the problem of high attenuation a new project has started

§  The idea is to design an new version of the feedthrough with higher response

§  Antrag is approved and the project has started


Vielen Dank an MDI

für die gute Zusammenarbeit!


The End


Additional Slides


>  Alternative manufacturers §  Microtest Inc.

§  VACOM: Vakuum Komponenten & Messtechnik GmbH

§  allectra

§  EUROMAT GmbH



40 GHz Mach-Zehnder-Modulator – EOM

>  40 Gb/s available

>  But 40 Gb/s ≈ 25 GHz analog bandwidth

>  40 GHz bandwidth → customized

>  Specifications:

>  Manufacturer:

Specifications Comment Analog Bandwidth [GHz] 40 Much more seems not possible Connector K Low Vpi < 5 V@1GHz External RF output nice to have Insertion loss [dB] < 6 Internal polarizator on the output Needed Internal cleanup PBC (background suppression) Dual fiber output ports nice to have 2 outputs: X and bar{X} Chirp Chirp free (Bias control + differntial detection) S11 [dB] < -10 PM fibers on input and output yes

EOSpace Thorlabs Photline u2t Heinrich-‐Hertz-‐Ins0tut



One record of an existing modulator with a bandwidth > 40 GHz



>  Low cost solution –> 4300 €

>  Photline MXAN-LN-40

>  3dB-Bandwidth > 28 GHz

>  Internal photo diode


>  Attenuation by approximation of 2.5 m Times Microwave SiO2 cable

Discussion and decision about RF cables

Documents

Development of the 40 GHz Bunch Arrival Time Monitor Pickup · Nils Mildner Antonio des Zubiaurre Wagner Jens Tiessen ! MSK (Beam control) Christopher Gerth Holger Schlarb Martin