cell coupled drift tube linac n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Cell-Coupled Drift Tube Linac PowerPoint Presentation
Download Presentation
Cell-Coupled Drift Tube Linac

Loading in 2 Seconds...

play fullscreen
1 / 24

Cell-Coupled Drift Tube Linac - PowerPoint PPT Presentation


  • 124 Views
  • Uploaded on

Cell-Coupled Drift Tube Linac. M. Pasini, CERN AB-RF. Contents. CCDTL concept and design Beam parameters Layout Test and measurements of the CERN pre-prototype Test and measurements of the ISTC prototype Summary. • • •. bl. bl. bl. bl. 3/2 bl. CCDTL concept and design.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Cell-Coupled Drift Tube Linac' - julio


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
cell coupled drift tube linac

Cell-Coupled Drift Tube Linac

M. Pasini, CERN AB-RF

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

contents
Contents
  • CCDTL concept and design
  • Beam parameters
  • Layout
  • Test and measurements of the CERN pre-prototype
  • Test and measurements of the ISTC prototype
  • Summary

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

ccdtl concept and design

• • •

bl

bl

bl

bl

3/2 bl

CCDTL concept and design
  • CCDTL = Cell Coupled Drift Tube Linac
  • Accelerating gap and Drift Tubes do not change within the single tank
  • Quads are placed between the tanks not inside the DTs
  • Intertank spacing is constant (250 mm)

The resonating mode is π/2

250 mm

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

ccdtl mechanical design 1 2
CCDTL mechanical design (1/2)

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

ccdtl mechanical design 2 2
CCDTL mechanical design (2/2)
  • Each accelerating tank is split in two halves
  • The CCDTL half-tanks are made out of copper-plated stainless steel, with cooling channels directly machined in the external part of the tank cylinder
  • Each half-tank contains a drift tube made in copper and cooled via the supporting stem
  • Vacuum seals and RF joints between half tanks and coupling cell are provided by “Helicoflex” type of gasket

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

mechanical details
Mechanical details

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

beam parameters
Beam Parameters

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

ccdtl layout
CCDTL layout

CCDTL module

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

ccdtl layout 50 102 5 mev
CCDTL Layout 50-102.5 MeV

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

slide10

Geometry details

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

coupling factors field stability
Coupling factors – field stability
  • Measured coupling factors from the prototypes at low energy (40 MeV) k = 0.89% (simulated was 0.88%)
  • Simulated coupling factors at high beta (100 MeV) k = 0.52%

50 kHz tuning error in 5 resonating cell

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

tuning requirements
Tuning requirements
  • 1 fixed tuner per half tank and 2 per coupling cell
  • 1 moving tuner at low energy to compensate for temperature drift
  • 2 moving tuners at high energy to compensate for temperature drift

∆T of 10 degrees should give a frequency variation of about 40 kHz (estimate)

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

cern pre prototype
CERN pre-prototype

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

measurements results
Measurements results

Q0=27281 which is 79% of Superfish (the plating is only

in one half of the Helicoflex joint groove)

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

spectrum measurements
Spectrum Measurements

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

high power test area
High power test area

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

high power measurements
High Power Measurements
  • Started with vacuum level of 10-8 mbar
  • Conditioning lasted less then 2 days
  • Max field achieved is 34.2 MV/m on the drift tube
  • Kp = 1.72
  • E0 = 4 MV/m
    • The temperature on the cavity was monitored: at 0.1% duty cycle the temperature was stabilized at around 30 deg with a minimum of 5 l/min water flow only in the drift tube. 7 kHz shift was observed in the resonance frequency
  • At SPL duty cycle temperature reached 58, 76 and 80 degrees in the drift tube holder, coupling iris and plunger tuner. In particular the temperature rise in the coupling iris is due to the over-coupled matching between waveguide and cavity; the resonant frequency decreased by 128 kHz from cold to hot condition.

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

status of the istc prototype
Status of the ISTC prototype

RFNC-VNIITF, Snezhinsk

BINP, Novosibirsk

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

measurements results1

Comparison of the field profile measurements done at CERN and at BINP (green)

Measurements results

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

alignment checks
Alignment checks

Alignment shaft

Alignment flange

2

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

waveguide coupling measurements
Waveguide coupling measurements

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

installation in the bunker and final tuning
Installation in the bunker and final tuning
  • Frequency: 0-mode 350.974 MHz
  • π/2-mode 352.060 MHz
  • π-mode 353.219 MHz
  • k = 0.9%
  • The frequency change of the π/2-mode after vacuum was +84 kHz.
  • Q0=36700 which is 84% of Superfish value.

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

high power measurements1
High power measurements
  • Conditioning of the cavity lasted about 1 week. (An increased pumping capacity with an automatic conditioning routine will probably decrease the time for conditioning)
  • After the conditioning we could easily put power inside the cavity in excess of 330kW at both Linac4 duty cycle (0.1%) and SPL duty cycle (5%). Nominal gradient requires 310 kW.
  • The power was limited by the high voltage power supply (60kV instead of 100kV)
  • The temperature on the cavity was monitored: at 5% duty cycle the temperature on the external part of the drift tube raised by 40 degrees, while tuners in the accelerating cells went up to 100 deg. C. The resonant frequency decreased about 80 kHz.

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008

summary
Summary
  • A new layout of the CCDTL has been optimized
  • Test and measurements of the CERN pre-prototype and ISTC prototype are completed. The cavities didn’t show any limitation in reaching the nominal field and beyond.
  • For the LINAC4 duty cycle a limited amount of cooling water (~5l/m) is required for the drift tubes
  • For the SPL duty cycle additional cooling must be added in the tuners

LINAC4 Machine Advisory Committee 1st meeting CERN January 29-30, 2008