Overview of Thesis 1. Design of the room temperature QWR for PXIE - - PowerPoint PPT Presentation

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Overview of Thesis 1. Design of the room temperature QWR for PXIE - - PowerPoint PPT Presentation

Oct 05, 2023 48 likes •491 views

Overview of Thesis 1. Design of the room temperature QWR for PXIE MEBT 2. Studies of the slow frequency tuner for 650 MHz cavities 3. Analysis of the LFD compensation in long pulse operation test in CM1 at NML Roman Kostin APC Beam Physics

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SLIDE 1

Overview of Thesis

Roman Kostin

APC Beam Physics Meeting, May 18, 2012

  • 1. Design of the room temperature QWR for

PXIE MEBT

  • 2. Studies of the slow frequency tuner for

650 MHz cavities

  • 3. Analysis of the LFD compensation in long

pulse operation test in CM1 at NML

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SLIDE 2

Overview of Thesis

  • 1. Design of the room temperature QWR for

PXIE MEBT

  • 2. Studies of the slow frequency tuner for

650 MHz cavities

  • 3. Analysis of the LFD compensation in long

pulse operation test in CM1 at NML

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SLIDE 3

Mechanical Design of Room Temperature Quarter Wave Buncher

Tuners ports

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SLIDE 4

Main RF Parameters

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SLIDE 5

Tuner

Goal: Range of frequency change 200 kHz for two tuners

Length, L (mm) Detuning range vs. tuner insertion for two different diameters of tuner Frequency detuning (kHz)

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SLIDE 6

Frequency change due to Atmospheric pressure

Units mm inches Thickness of cylindrical wall 7,937 5/16 Thickness of Up and Bottom walls 9,525 3/8

Total displacement (left) and von Mises stresses

  • f CW re-buncher under

1 atm pressure.

Frequency of undeformed cavity, MHz 162,420376 Frequency of deformed cavity, MHz 162,416223 Frequency shift, kHz

  • 4,1

Yield Stress 250 MPa

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SLIDE 7

Termo Analysis for two designs of cooling channel in the spoke (Voltage 130 kV)

Inside spoke In cylindrical Inner diameter of cooling channel d, mm 4,73 5,95 Temperature of cooling water, оС 30 30 Velocity of water, m/s 3 3 Convection coefficient, W/(m2оС) 14700 14100

*Note: Nominal Voltage is 70 kV “All around tubing” design (left) and “V-Channel” design (right) Two types of cooling channels:

  • Inside spoke
  • In cylindrical part of cavity

Table: Parameters of cooling system

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SLIDE 8

Geometry

“V-channel” Design

Temperature distribution ( T° C) Voltage 130 kV

64.7 30.5

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SLIDE 9

Displacements, m Von Mises Stress, Pa

Frequency of undeformed cavity, MHz 162,420336 Frequency of deformed cavity, MHz 162,371870 Frequency shift, kHz

  • 48,466

Deformation and stresses

8E6 4000 0.95E-4

Yield Stress 250 MPa

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SLIDE 10

“All around tubing” Design

Geometry Temperature distribution ( T° C) Voltage 130 kV

50.5 30.5

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SLIDE 11

Displacements, m Von Mises Stress, Pa

Frequency of undeformed cavity, MHz 162,421487 Frequency of deformed cavity, MHz 162,383582 Frequency shift, kHz

  • 37,9

“All-around tubing”: Deformation and stresses

120E6 8910

Yield Stress 250 MPa

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SLIDE 12

“All Around Tubing” Design for V=100 kV

Displacements (m) Temperature distribution (T° C)

0.3E-4 41.5 30.3

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SLIDE 13

Von Mises Stress, Pa

Frequency of undeformed cavity, MHz 162,421487 Frequency of deformed cavity, MHz 162,400165 Frequency shift, kHz

  • 21,3

6.72E6 5003

Yield Stress 250 MPa

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SLIDE 14

Spoke Vibration: Stability requirements

  • Determine frequencies of mechanical modes
  • Determine Amplitude of ground motion and evaluate

amplitude of the spoke oscillation

  • Determine a value of spoke shift to exceed the criteria of

stability

Goals: RF constrains from Beam dynamics:

  • Shift of the Phase < 1 degree
  • Reduction of the Gain < 1 keV
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SLIDE 15

Natural frequencies of QWR

Perpendicular Oscillations

134 Hz 351 Hz 418 Hz

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SLIDE 16

110 Hz 342 Hz 418 Hz

Longitudinal Oscillations

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SLIDE 17

Stiffness of the Spoke k, MN/m 0.2 Ground Motion Amplitude Ag, nm 1 Q 1000 Mass of the Spoke m, kg 2.5 Resonance frequency f0, Hz 110 Spoke Amplitude Xmax, mkm 0.6

Ground Motion data

Simplified mechanical model: Was taken the most noisy case, i.e. HERA.

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SLIDE 18

Deviation of cavity amplitude and phase vs. amplitude of spoke shift.

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SLIDE 19

Summary

  • The tuner design is fixed to 40 mm dia. Two of them

will provide the frequency up to 200 kHz.

  • Frequency shift because of the atmosphere pressure

is -4.1 kHz

  • Expected frequency shift due to heating for 100 kV is
  • 21.3 kHz
  • Expected amplitude of vibration of the spoke

because of the ground motion is far away to exceed criteria of stability (0.6 mkm << 600 mkm)

  • The QWR design meets all requirements
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SLIDE 20

Overview of Thesis

  • 1. Design of the room temperature QWR for

PXIE MEBT

  • 2. Studies of the slow frequency tuner for

650 MHz cavities

  • 3. Analysis of the LFD compensation in long

pulse operation test in CM1 at NML

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SLIDE 21
  • Oct. 19-29, 2008

Lecture 7: SCRF & ILC

Tuners tested in HoBiCaT

Modified piezo holder frame: Higher wall thickness

Principle (similar to Saclay I tuner)

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SLIDE 22
  • Oct. 19-29, 2008

Lecture 7: SCRF & ILC

Tuners tested in HoBiCaT

Modified piezo holder frame: Higher wall thickness

Principle (similar to Saclay I tuner)

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SLIDE 23

Tuner for 650 MHz elliptical cavity with β=0.61

Frequency range, kHz 200 Advantage (transformation ratio) 30 Cavity Sensitivity, Hz/mkm 300 Cavity Stiffness, kN/mm 19

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SLIDE 24

Geometry of Half Model

Joint 1 Joint 2 Joint 3 Main Lever Driving Lever Driving Pin Pins for Driving Motor Bars

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SLIDE 25

Displacements, m

Analysis without Cavity

Displacements

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SLIDE 26

Von Mises Stress, Pa

Stress

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SLIDE 27

Displacements, m

Analysis with Cavity

Displacements

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SLIDE 28

Von Mises Stress, Pa

Stress

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SLIDE 29

Summary

Without Cavity With Cavity Advantage 32.5 38.9 Max Stress, MPa 9.4 56

  • ANSYS Analysis shows that proposed model is fully operational
  • Advantage is about 30
  • Maximum value of stress is far away from yield stress of stainless

steel ( 400 MPa)

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SLIDE 30

Overview of Thesis

  • 1. Design of the room temperature QWR for

PXIE MEBT

  • 2. Studies of the slow frequency tuner for

650 MHz cavities

  • 3. Analysis of the LFD compensation in long

pulse operation test in CM1 at NML

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SLIDE 31

Project X Pulsed Linac requirements

  • TESLA-style cavity. Gradient 25 MV/m,

QL=1·107;

  • LFD below 20 – 30 Hz
  • Long RF Pulse 9 ms, were fill time is 4 ms and

flattop is 5 ms

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SLIDE 32

Collected data consist 3 cases

QL: 3·106; 6·106; 1·107; Eacc: 18MV/m; 25 MV/m; 24.5 MV/m; RF power per cavity: 40 kW; 50 kW, 60 kW

Data were collected from CM1 in NML

Was used only one 120 kW klystron, because of that

  • nly two cavities were powered (#5 and #6)
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SLIDE 33

LORENTZ FORCE COMPENSATION FOR LONG PULSES IN SRF CAVITIES

LFD Compensation in C5 and C6 during a 9ms RF pulse at Eacc=25MV/m and QL = 6*107. (A): Baseband envelopes of the forward and cavity field probe signals. (B): Residual detuning using following compensation. Adaptive LFD algorithm. (C): Piezo drive waveforms.

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SLIDE 34
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SLIDE 35
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SLIDE 36
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SLIDE 37
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SLIDE 38
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SLIDE 39
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SLIDE 40
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SLIDE 41
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SLIDE 42

Summary

  • In all 3 cases detuning pk-to-pk is about ±10

Hz

  • Analyzing shape of forward signal were

discovered that were used wrong settings for cavity gradient

  • Vector Sum of Amplitude and Phase much

more stable than for individual cavities

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SLIDE 43

Special thanks to:

  • N. Solyak
  • V. Yakovlev
  • W. Schappert
  • Y. Pischalnikov
  • I. Gonin
  • G. Romanov
  • E. Borisov

I am very pleased to work with you!

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SLIDE 44

Thank you for watching