Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
1 "Advances in Electro polishing of Niobium Resonators" Axel
Matheisen, DESY Hamburg for the CARE JARI WP 5 collaboration
partners
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
2 Short overview on Status at start of Jari 1 Hardware problems and
improvements Quality control (acid management) Sulfur segregation
and ethanol rinse Summary
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
3 Status of EP facilities at Start of Care Jari 1 @ DESY multi cell
EP bench: hardware set up in 2003 and operational in study mode
Chemistry lab: under construction to be modified for EP test set up
@ CEA Saclay and INFN Legnaro Sample test facilities available
Single cell setup to be ordered and to be installed at project
start Changes in respect o proposal during the Program of WP 5 Set
up and legal procedures for single cell EP apparatus took more time
than expected For WP 5 the DESY EP bench is use to optimize
parameters for EP processes.
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
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6 To study best parameters the following problems needed to be
fixed System not operational due to high HF System operation: out
gassing of HF from the acid mixture is extremely high commercial HF
absorbers not sufficient Life time of acid and its influence on
cavity gradients and the process Hardware problems and
improvements
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
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8 Operation data of DESY EP bench beginning of 2005
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
9 View on commercial wet Gas scrubber View on gas exhausting pipes
of commercial gas scrubber Commercial EP absorber limits treatment
time (low efficiency for large amounts of HF gases)
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
10 1 / liter ; Volume 8*10 l in cascade cartige / life time
8*10Hours of EP Dry HF absorbent installed at the point of
appearance HF Absorbent COSA D in commercial cartridge HF Absorbent
COSA D in cascade cartridge (Part of Ouality control of acid
mixtures)
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
12 Receipt most common and in use at DESY * Mix 9 volumes of H2SO4
(>96%) and 1 volume of HF (>45%) Apply 17 Volt DC voltage
Studies in test mode showed best parameter for shine surfaces and
optimized process time 1a) theory of acid mixture Quality control
(Acid management) Electro chemical reaction of the ep process
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
13 HF Evaporation 1:9 [HF(45%) / H2SO4 (96%) ] + H2O due to
hygroscopic reaction of H2SO4! H2SO4 + H2O ----> H2SO3 + H2SO4 +
HF ----> FSO3H + H2O HF +H2OFSO3H H2SO3 H2SO4 HF 1.bReality of
the EP prescription HF Consumption
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
14 It was found that Out gassing strongly depending on way of
mixing the acid procedure to be fixed for acid mixing Observation
a) strong differences in gaseous HF evaporation from batch to batch
b) Differences in removal rates / current from batch to batch c)
Differences in gaseous HF evaporation from supplier to
supplier
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
15 2) Analysis of H2 content of acid mixture for different
procedures of mixing
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
16 Conclusion from observations: QC methods have to be installed to
control delivered acid!! define and control acid parameters to
study the EP process
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
17 Diagramm 2:Versuch 1 bei 30C, HF-Gehalt relativ zur frischen
Sure 3a) Determine acid mixture by U/ I on test apparatus SRF
Documents 2004-001 HF content in Mixture U/I diagram at 30 C
treatment temperature
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
18 SRF Documents 2004-001 U/I diagram at 30 C treatment temperature
3a) Determine acid mixture by U/ I on test apparatus
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
19 3b)Measure removal rates indicator for aging of acid Removal
rate calculated from weight difference before and after EP (
treatment time of more than 120 Min)
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
20 SRF Documents 2004-001 3c) Aging of acid studied with U/I test
apparatus
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
21 for large scale production find industrial acid management and
instruments to be applied as QC and process control instrument
Study on acid management by industry launched (Henkel
Lohneletropolitur) Study to be done in 3 phases 1: Define best
instruments for research and production 1.1 Overview of commercial
systems 1.2 examine commercial systems with standardized mixture 1.
3 evaluate best candidates 2: Define sensitivity and
reproducibility of evaluated systems 3: Apply systems in process
and examine handling
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
22 Part 1 published at TTC Meeting 26.9.06 WG 3 by C.Hartmann
TTC-Meeting at KEK 2006 Sept.25-28, 2006 Analysis technique of the
HF-H2SO4-electrolyte Christian Hartmann Henkel Lohnpoliertechnik
GmbH
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
23 Conclusion of study part 1 VerfahrenAnalyse Gertekosten in
AnalysedauerAnalysekosten Empfehlung Henkel AASElementanalyse
15.000 bis 50.000,- 2 min / Analyse fr 10 Elemente 128,- /Std.
Labor nein ICP-OESElementanalyse Alle Elemente parallel ca.
60.000,- 3 min / Analyse fr 20 Elemente 128,- /Std. Labor ja IC
Ionenchromatographie Ionen (SO4, F-, FSO3H) 15.000,- bis 20.000,-
20 min / Analyse 128,- /Std. Labor ja TOC Total Carbon Org.
Verunreinigungen 15.000 bis 25.000,- ca. 15 min / Analyse 128,-
/Std. Labor ja FTIR-ATR (Infrarot) Ionen (SO4, F-, FSO3H ?)
82.000,- + 27.000,- 3 min / Analyse Miete 500,- / Woche Evtl.
tiefer einsteigen NMR Org. Verunreinigungen 100.000,- bis 4 Mill.
15 min / Analyse 150,- / Analyse nein CE Kapillarelektrophorese
Ionen (SO4, F-, FSO3H) 25.000 bis 53.000,- 60 min / Analyse 2.500,-
/ 10 Proben ja CE oder ITP ITP Isotachophorese Ionen (SO4, F-,
FSO3H) 26.000,- 20 min / Analyse 1.000,- + 70,- Probe ja CE oder
ITP TitrationGesamtsuregehalt 10.000 bis 15.000,- ca. 30 - 45 min /
Analyse 1000,- pro Tag sinnvoll
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
24 Care conf 05-030- srf Sulfur segregation and ethanol rinse
Electro-polishing Surface Preparation for High Gradient Cavities at
DESY A.Matheisen, H.Morales, B. Petersen, M.Schmkel, N.
Steinhau-Kuehl Deutsches Elektronen Synchrotron DESY, Hamburg,
Notkestrae 85, 22602 Hamburg, Germany PAC 2005
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
25 Observations on maintenance after 100 h of operation Electrode
N2 overlay pipe located on top of electrode
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
26 Conclusion : En milieu sulfurique concentr ([H2SO4] thor. 8,94
0,12 mol.L-1) et chaud (30 et 40C), laluminium ragit avec les
anions sulfates pour conduire : A la formation de soufre
cristallis, en quantit plus ou moins importante et partir de la
raction (8) ou (8) suivante : 2 Al + SO42 + 8 H+ 2 Al3+ + S + 4 H2O
(8) 2 Al + 4 H2SO4 conc. Al2(SO4)3 + S + 4 H2O (8) A la synthse
effective dhydrogne sulfur H2S gazeux, partir du soufre prcdemment
form et lorsque [H2SO4 / [H2O] > 1,00 0,05 (tests A, B et G).
Son mcanisme de formation scrit : 2 Al + 3 S + 6 H+ 2 Al3+ + 3 H2S
(9) ou 2 Al + 3S + 3 H2SO4 conc. Al2(SO4)3 + 3 H2S (9) IMPURETES
Aluminium et Soufre Dans Les Bains dElectropolissage (Systmes
ternaires HF H2SO4 H2O) De Matrices Niobium A. ASPART, F. EOZENOU,
C. ANTOINE DSM/DAPNIA/SACM/LESAR CARE-Pub-05-004 Origin of sulfur
in the EP process ?
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
27 PLANCHE PHOTOGRAPHIQUE8 ATTACK of Aluminumby H 2 SO 4 16.1 mol.L
-1 to T BATH = 40C t =562 min, scale = x1000, e Al = 59.2 m t =712
min, scale = x1000,e Al = 74.8 m
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
28 4 Sulfur found in test set upSulfur sediments on DESY EP set
up
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
29 PLANCHE PHOTOGRAPHIQUE6 ATTACK ofAluminumby H 2 SO 4 16.1 mol.L
-1 to T BATH = 30C:Test"A" t = 955 min, scale = x500, eAl = 37.8 m
e Al = 37.8 m t = 955 min, scale = x500, after washing by CHCl
3
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
30 Conclusion: Origin of sulfur found Not connected to Nb removal
process Sulfur is build up inside the Cavity on the electrode
Method's to cure A) Filter not effective origin is inside the
Cavity + S will plug filter B) Use inert metal for electrode
Platinum Solid electrode need: body guard for the electrode
Plating: Only on short sections; acid exit hole can not be plated
C) Dissolve without effecting the Nb surface quality
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
31 Experiments on tube with sulphur layer before after ethanol
cleaning
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
32 [fe limit = Eacc @ 1*exp-2 mGy/min in vertical tests step up @
DESY] Rf test results after fine EP treatment [no120 C bake!!!!]
Limited by weld problem
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
33 Comment: FE Limit = Max. allowed radiation level (2*10 -2
mGY/min for module acceptance of Cavities measured in vertical
insert at DESY Influence on 120 C baking on cavities with alcohol
rinse applied
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Axel Matheisen DESY Hamburg @ CARE 07 Meeting Cern Switzerland
34 Summary The multi cell apparatus at DESY is reproducible in
operation operational since a new HF absorber system with high
reliability and low cost is installed Optimized parameters for the
EP test bench of multi cell 1,3 GHz resonates are fixed Parameters
for reproducible acid mixtures are fixed. A quality control and
acid management system is launched and will be continued Source of
sulfur causing fieldemission is located Application of ethanol
rinse showed improvements on fieldemission level Basic studies
don't show limitations related to apparatus or acid if all process
parameters are set properly