WP 9.2: DDS Status

WP 9.2 DDS Status, R.M. Jones, 25th Oct 2010, WebEx Phone-in, GenevaWP 9.2 DDS Status, R.M. Jones, 25th Oct 2010, WebEx Phone-in, Geneva 1

WP 9.2: DDS Status

Roger M. JonesCockcroft Institute and

The University of Manchester

WP 9.2 DDS Status, R.M. Jones, 25th Oct 2010, WebEx Phone-in, Geneva


192 cells8-fold interleaving

24 cellsNo interleaving

192 cells8-fold interleaving

Manifold

Coupling slot

Dipole mode Manifold mode

∆fmin = 65 MHz∆tmax =15.38 ns∆s = 4.61 m

∆fmin = 8.12 MHz∆tmax =123 ns∆s = 36.92 m

∆f=3.6 σ =2.3 GHz∆f/fc=13.75%

Summary of CLIC_DDS_C

Meets design Criterion?


14.4ε 2.07ε

Circular Square

ε=-8.28ε=-4.14

ε=-2.07

Convex ellipticity

Concave ellipticity

Single undamped cell Iris radius=4.0 mm

CLIC_DDS_E Elliptical Design –E Fields

1ε ε

1.38ε


Circular Rectangular Elliptical(Convex)

Elliptical(Concave)

of cavity 1 ∞ 4.14 2.07 1.38 0.82 0.41 -8.28 -4.14 -2.07

facc(GHz) 12.24 12.09 11.98 12.0 11.99 11.98 11.98 11.9911 11.9919 11.9935

Eacc(V/m) 0.43 0.43 0.42 0.43 0.43 0.42 0.42 0.43 0.43 0.42

Hsur max /Eacc

(mA/V)3.64 4.86 4.71 4.54 4.29 3.75 3 4.94 4.99 5.11

Esur max /Eacc 2.27 2.27 2.33 2.28 2.28 2.33 2.33 2.27 2.27 2.33

Iris radius = 4. 0 mmIris thickness = 4.0 mm

CLIC_DDS_E Elliptical Design, Single Undamped Cell Dependence of Fields on

Chosen design




Undamped

Damped

Qavg ~1700

CLIC_DDS_A WakeWake of a non-interleaved 24 cell structure –first structure of 8-fold interleaved structure chosen.Motivated by high gradient testingWake is measurable and provides a useful comparison to simulations (but will not, of course, meet beam dynamics criteria)

WP 9.2 DDS Status, R.M. Jones, 25th Oct 2010, WebEx Phone-in, GenevaWP 9.2 DDS Status, R.M. Jones, 25th Oct 2010, WebEx Phone-in, Geneva

Matching CLIC_DDS_A

Firstly, match-out either end of structure with regular cells: Structure for test will utilise a mode launcher Initially, simulate a structure with one regular cell and two matching cells at

either end and we study the minima in S11 as a function of the geometrical parameters of the matching cells (a, L –adopt L variation, rather than b, from space considerations)

Add additional (2, then 3) identical standard cells (const. imp) and follow the same procedure and modify parameters of matching cells to minimise S11

The matching condition (on a, L) is that which coincident with all 3 simulations. Secondly, once complete, match-out the full, tapered structure based on this

match.

I/P


Beam

Port11Port 2 E-field

CLIC_DDS_A Match-out the full, tapered structure E-field and S11 shown

~198.6mm

Matching cell

Surface E-Field Axial E-Field

5.0

A. D’Elia

7.5

E s (V/

m x

104 )

E z (V/

m x

104 )

z (mm) 0 300

7

z (mm) 0 225


CLIC_DDS_A Eng. Design


Water pipes for cooling Vacuum flange

Vacuum flange

Power input

Power outputTuning holes

Cutaway-view

Beam

V.Soldatov

Mechanical Eng. Design of DDS_A


DDSA, Reverse Side View

CLIC_DDS_A Prototype Disks

DSA, Front View

VDL Fabricated.G. Riddone, Oct 15th 2010!.

8mm


• Shape accuracy 5 µm 1.7 µm achieved• Roughness Ra 0.025Iris region achieved Ra 0.010

Low-force probe: some disks show measuring indents (20 nm depth) after probing on the CMM Local hardness of the material is not constant.

Cell Qualification of CLIC_DDS_AVDL (NL) have machined and measured several cells –end cells. New!(recvd by CERN Oct 2010)Global profiles made with Zeiss CMM, free state measurement are illustrated for disk 24Design, tolerance bounds and achieved profile shownETA of all cells –December 2010Bonding of complete structure by 1st quarter of 2011.


I/P at/2=15.9GHz

Work in Progress/R&D Opportunities CLIC_DDS_A is equipped with mode

launchers CLIC_DDS_B includes full HOM

ports Initial studies on matching the HOM

coupler for CLIC_DDS_B in progress (dipole band ~ 15.9 GHz – 18 GHz)

Sic

Sic

Moving to a high phase advance (HPA) structure allows other parameters to be optimised

5/6 phase advance structure design in progress (for initial design see Linac2010)

In the HPA design further features being explored

Additional manifold (8) Influence of SiC rods on overall Q

EnhancedCoupling

Standard DDS Manifold

Additional Manifold


Status CLIC_DDS_A : RF (inc. mode launcher) and mechanical design has been completed.

Qualifications cells fabricated Oct 2010! (VDL, NL)–all cells expected Dec 2010 Structure will be subsequently bonded in the first quarter of 2011 -ready for high power

testing in 2011 at the CLIC test stand. Status CLIC_DDS_B: Equipped with HOM couplers –design underway New CLIC_DDS R&D in progress: HPA : High phase advance (5/6) design is being studied. Allows optimisation of

remaining parameters –minimise surface fields, wakefields at stipulated vg, maximise luminosity and efficiency

Novel enhancements to wakefield optimisation with a view to optimising efficiency and increasing luminosity –additional manifolds, SiC rods.

Submitted joint (CERN et al) proposal to participate in FACET wakefield tests (important to verify DDS wakefield simulations)

More details here:http://ilcagenda.linearcollider.org/getFile.py/access?

contribId=526&sessionId=83&resId=1&materialId=slides&confId=4507

Final Remarks

WP 9.2: DDS Status

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