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CEA-Saclay Activities - TESLA Technology Collaboration - Desy

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<strong>CEA</strong>-<strong>Saclay</strong> <strong>Activities</strong><br />

• CARE / SRF<br />

– Suface Preparation - Electropolishing<br />

– Cold Piezo-Tuners<br />

– Horizontal cryostat CRYHOLAB tests<br />

– Cold reentrant BPM<br />

• TTF2 : Beam loss electronics<br />

• TTF2 : HOM<br />

• EuroTeV : Collider design<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 1


CARE-SRF : Surface Preparation - EP<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 2


CARE-SRF : Surface Preparation - EP<br />

Electropolishing of single-cell cavities<br />

• Single-cell EP Set-up, purchased from CERN<br />

• Installation and upgrading is underway<br />

• Commissionning in <strong>Saclay</strong> foreseen early 2005<br />

5.- EP on single cell<br />

5.1.1 EP on samples<br />

5.1.1.1 Establishing method of surface characterization<br />

(roughness, reflectometry)<br />

5.1.1.2 Surface characterization fixed<br />

5.1.1.3 Series of EP with samples for surface investigation<br />

5.1.1.4 Best EP parameters<br />

5.1.2 Single cell cavities<br />

5.1.2.1 Order Nb and fabricate 3 cavities<br />

5.1.2.2 3 cavities fabricated<br />

5.1.3 EP chemistry on single cells<br />

5.1.3.1 Design of EP set up<br />

(90%)<br />

5.1.3.2 Fabrication of EP set-up<br />

5.1.3.3 Commissioning of EP set-up<br />

5.1.3.4 First operation of EP set-up<br />

5.1.3.5 Operation of EP set-up<br />

(30%)<br />

(50%)<br />

(20%)<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 3


CARE-SRF : Surface Preparation - EP<br />

Series of EP with samples<br />

• Gloss measurements allow fast evaluation of surface state<br />

• No correlation between etching rate and surface state<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 4


CARE-SRF : Surface Preparation - EP<br />

Rotating sample holder<br />

@ 16 V :<br />

• t = 470mn, d A-C<br />

=22 mm,<br />

Rem.Thick. = 160 µm<br />

• t = 470mn, d A-C<br />

= 92mm,<br />

Rem.Thick. = 80 µm<br />

EP bath<br />

• t = 300mn, d A-C<br />

=2.2mm,<br />

Rem.Thick. = 157 µm<br />

• Standard sample holder<br />

Rotating sample holder:<br />

(reproduces cavity<br />

geometry, exposure to air,<br />

rotation….)<br />

• Rotating anode: surface state differ considerably from what usually found<br />

on samples => better tool to estimate optimal conditions on cavities<br />

• Several bath compositions will be tested with design of experiment<br />

techniques (statistical tool => modelisation of the behavior of any bath<br />

composition)<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 5


Surface Preparation<br />

Other activities : Replica @ the quench site<br />

a) b) c)<br />

Contour line of replicas, modelling of the edge profile and β (field<br />

enhancement factor) for a) first quench site, b) same area after 20 µm<br />

etching, c) new quench location.<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 6


CARE-SRF : Cold Piezo Tuner<br />

•Old design : last batch of 16+3 tuners sent to DESY<br />

•New design of cold tuner: pre-study finished<br />

includes 2 piezos<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 7


CARE-SRF : Cold Piezo Tuner<br />

New design of cold tuners with:<br />

• SOLEIL upgrades<br />

• larger rigidity<br />

• Fabrication of 2 tuners (beginning of 2005)<br />

• 12 NOLIAC piezos, 2 PHYTRON stepping motors ordered<br />

• Coll. with IPN Orsay: <strong>CEA</strong> send NOLIAC piezos to IPN for<br />

characterization, and IPN send P.I. piezos for tests on tuners<br />

• Coll. with INFN-Milano for measurement with stress sensors @ 2K<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 8


CARE-SRF : Cold Piezo Tuner<br />

New design of cold tuner<br />

The preload on the piezos is defined by the cavity<br />

compression strength, therefore by the cavity frequency<br />

tuning:<br />

1 - before chemical treatment (field flatness)<br />

2 - pre tuning before cooling<br />

Rough estimation on the uncertainty of the preload<br />

value at cold from 300 N to 2000 N<br />

(« optimum » preload for the piezo NOLIAC ~ 600N)<br />

⇒ Need to optimize the frequency tuning<br />

⇒ Integrated Cavity Tests in CRYHOLAB<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 9


CARE-SRF : CRYHOLAB tests<br />

Adaptation :<br />

cavity handling<br />

and support<br />

Preparation : → April 2005<br />

1 st series (Magnetostrictive & <strong>CEA</strong> tuners): summer 2005<br />

2 nd series ( IN2P3 activity – LAL coupler) : spring 2006<br />

3 rd series ( INFN tuner ) : autumn 2007<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 10


Cold Reentrant BPM<br />

Measurements in ACC1<br />

(D. Noelle, M. Wendt)<br />

• Raw signals (measured directly<br />

with an oscilloscope at the output<br />

cables) are clean.<br />

• (Analog) electronics will be<br />

connected next month.<br />

New cavity design<br />

• A new reentrant cavity will be<br />

fabricated with some changes<br />

(easier cleaning, mechanical<br />

interfacing).<br />

• Reliability of feedthroughs during<br />

thermal cycles will be improved.<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 11


Beam Loss Electronics<br />

TTF 2 beam loss protection electronic board<br />

BIS<br />

Upstream<br />

Downstream<br />

Toroids<br />

<strong>TESLA</strong> collaboration meeting -LAL Orsay<br />

07/09/2004 12


Beam loss Electronics<br />

Beam Tests on (T1-T2) toroids across ACC1<br />

SACM/LESAR / September 2004 - Orsay<br />

07/09/2004 13


Amplitude [dBm]<br />

−25<br />

−30<br />

−35<br />

−40<br />

−45<br />

−50<br />

−55<br />

−60<br />

HOM (coll. with DESY)<br />

Beam Measurements on ACC1<br />

• Studies on alignment in the <strong>TESLA</strong> cavities based on<br />

the signals from the HOM couplers started on ACC1<br />

Dipole<br />

passband<br />

1 (TE-like)<br />

2 (TM-like)<br />

Cavity 1, HOM coupler 1<br />

Passband 1, mode #6<br />

Pol. 1: 1703.363 MHz<br />

Pol. 2: 1704.223 MHz<br />

Mode #<br />

6<br />

7<br />

4<br />

5<br />

Frequency<br />

(simulation) [MHz]<br />

1713.7<br />

1738.3<br />

1864.7<br />

1872.7<br />

R/Q<br />

[MW/m 2 ]<br />

11.21<br />

15.51<br />

6.54<br />

8.69<br />

Polarisation axes<br />

randomly oriented<br />

in the transverse<br />

plane<br />

1.703 1.7035 1.704 1.7045<br />

Frequency [GHz]<br />

SACM/LESAR / September 2004 - Orsay<br />

07/09/2004 14


HOM (coll. with DESY)<br />

Beam Measurements on ACC1<br />

• Beam based alignment resolution of 50 µm w.r.t.<br />

cavity HOM axes<br />

Cav.: 1, Passb. 1, mode #6, Pol. 1<br />

Cav.: 1, Passb. 1, mode #6, Pol. 2<br />

y<br />

HOM Ampl. [a.u.]<br />

20<br />

15<br />

10<br />

5<br />

0<br />

x = −1.75 mm<br />

1→2<br />

a<br />

←y = 0.766 mm<br />

−2 −1 0 1 2 3<br />

25<br />

20<br />

15<br />

10<br />

5<br />

0<br />

y = 0.797 mm<br />

2 →3<br />

b<br />

←x = −4.83 mm<br />

−6 −5 −4 −3 −2<br />

polarization<br />

directions<br />

2<br />

3<br />

5<br />

4<br />

1<br />

x<br />

HOM Ampl. [a.u.]<br />

4<br />

3<br />

2<br />

1<br />

0<br />

2<br />

x = −4.85 mm<br />

y = 0.452 mm<br />

1.5<br />

3 →4 4 →5<br />

0.5<br />

c<br />

←y = 0.441 mm<br />

d<br />

←x = −4.85 mm<br />

0<br />

0.4 0.6 0.8 1<br />

−5 −4.9 −4.8 −4.7<br />

y [mm]<br />

x [mm]<br />

1<br />

SACM/LESAR / September 2004 - Orsay<br />

07/09/2004 15


EUROTeV : Collider Design<br />

<strong>Collaboration</strong> with Daresbury and LAL-Orsay<br />

• New Collimation and Final Focus designs<br />

• New IR design with crossing angle options<br />

IP<br />

QD<br />

QF<br />

2 mrad<br />

Nb3Sn SC quadrupole:<br />

prototype under construction (1m), will be tested in 2T<br />

external solenoid<br />

SACM/LESAR / September 2004 - Orsay<br />

07/09/2004 16

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