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Status of the low beta 0.07 cryomodules for SPIRAL2
P. Bosland, M. Anfreville, P. Carbonnier, F. Eozénou, C. Madec, L. Maurice,
A. Pérolat, P. Galdemard, O. Piquet, R. Ferdinand, et al.
To cite this version:
P. Bosland, M. Anfreville, P. Carbonnier, F. Eozénou, C. Madec, et al.. Status of the low beta 0.07 cryomodules for SPIRAL2. 2nd International Particle Accelerator Conference (IPAC’11), 2011, San Sebastian, Spain. MOPC079, pp.256-258, 2011. �in2p3-00636251�
STA
P. Bos
Abstract
The status supplied by t this paper. W performed o power tests 2010 and th first cryomod CEA Sacla beta (b=0.07 SPIRAL2 ac the realisatio The first step prototype,wh In a second been tested cryomodules in the machin and cryomo chemical tr assembly, RF RF power te Saclay. The power 40 kW CW i Grenoble lab mounted on Orsay [4]. The “cryo context of th the actual on had to be cryomodules cryomodule have the pos built at Sacla facility. Two RF p qualification April 2009 September 2 campaign th room at C dissipations modification cryomodule andthe configATUS OF
sland, M. A
s of the low b the Irfu institu We summaris on the cavitiof the quali e RF power t dule of the ser
INTRO
ay has in cha ) cryomodule ccelerator [1]. on, the prepar p consisted in hich reached
step a first (“ d before th s. This qualifi ne. All the co dules) are fa reatments, H F tests of the sts of the cryo r couplers spe in travelling w boratory [3]. the high be omodule A” he moving of ne at CEA Sac used for s assembling of the series. ssibility to wo ay for the XFE ower tests cam
cryomodule for the first 2010 for th he cryomodul ERN.The re in the cavity ns. The refur was made in guration of th
THE LO
Anfreville, P
Ga
R. Ferdin
Y. Góme
beta cryomodu ute of CEA Sa se in three p es in vertica ifying cryomo tests perform ries.ODUCTION
arge the deliv es, named cryo
This includes rations and th n the manufac the required “qualification” e production cation cryom omponents of abricated in HPR rinsing cavities in ve omodules are ecified for a m wave, are deli
The same eta cavities d project began
the laborator clay. Three dif the cavities
before asse Since the en ork in the new EL project at mpaigns were :between De t one, and b he second on le was assem esults showed [2] that led u rbishment of n the IPN O he qualificatio
OW BETA
P. Carbonnie
aldemard, O
nand, PE Be
ez Martínez,
ules for SPIR aclay, is report parts the RF al cryostat,the oduleperforme med in 2011 o
N
very of the 12 omodule A, fo s the developm he RF power cturing of a c performances ”) cryomodul n of the s odule will be the series (ca industry. Ca in clean r ertical cryosta performed at maximum pow ivered by theL couplers are developed by n in 2003 in ry from one s fferent clean r preparation embling the d of year 200 w facility that DESY sharing e performed o cember 2008 between April ne. For the mbled in the d very high us to make se f the qualific Orsay clean r on cryomoduleA 0.07 CR
er, F. Eozéno
. Piquet, Irf
ernaudin SP
, LPSC Gre
RAL2, ted in tests e RF ed in on the 2 low or the ment, tests. cavity s [2]. le has series used avities avities room, at and CEA wer of LPSC also y IPN n the site to rooms and first 09 we t was g this on the 8 and l and first clean h RF everal cation room, e was the LINA Al deliv cryo room Al SDM were first mid-befo room Fi copp Fr with Figu cavit out o mou seale scatt field spec lowe of th AZ4 nom the lRYOMOD
ou, C. Made
fu, CEA Sac
IRAL2/GA
enoble, CNR
nominal one AC. ll componen vered before module of the m at Saclay anRF TEST
VER
ll cavities hav MS and Z eperformed at in the old ins -2010. The higre vertical tes ms.
gure1: Q cur per bottom cap rom all the di h cavities in ure 1 summa ties with thei of copper. Th unted with an ed with a He teringof the c d reached by ification (Eac er than foresee he Q values fr 4 cavity islow minal field (Eac limit (Q0=4E
DULES FO
ec, L. Maur
clay
ANIL Caen
RS/IN2P3
e required fo nts of the s e the end e series was a nd was tested iTS OF THE
RTICAL C
ve been delive ZANON. Th t Saclay in t stallation and gh pressure ri sts) was perfo rves of the 6 ps. ifferent tests different con arise only thoir final dismo he first cavity indium seal. elicoflex gask cavities perfor the cavities cc=6.5MV/m), en.Last result rom one test t wer than the re
c=6.5 MV/m) 10 at E acc=6.5
OR SPIR
rice, A. Péro
or the install serial cryom of year 20 assembled in t in July 2011.E CAVITIE
CRYOSTAT
ered by two m he chemical two different then in the n insing (and th formed in 3 d cavities test that have bee nfigurations, tose correspon ountable botto
y AZ1 has it All the othe ket. RF tests rmances. The is always we , but Q leve ts seem to sho to the next.Th equired specif andthat of AZ 5MV/m). The
RAL2
olat, P.
ation on the modules were 010.The first the new cleanES IN
T
manufacturers: l treatments installations: new one since he assembling different clean
ted with their en performed the results in nding to the om cap made s bottom cap er cavities are show a large e accelerating ell above the els are often ow a decrease he Q0 value of fication at the Z6 cavity is at ese 2 cavities e e t n : s : e g n r d n e e p e e g e n e f e t s
MOPC079 Proceedings of IPAC2011, San Sebastián, Spain
256 Copyright c○ 2011 by IP A C’11/EPS-A G — cc Cr eati v e Commons Attrib ution 3.0 (CC BY 3.0) 07 Accelerator Technology T07 Superconducting RF
will be test treatment. Analyses a Q decrease th look at possi of the ultra-p a cryomodul after the RF be repaired.A was damaged be repaired.O on the Helico pressure up possible to r 11MV/m. At present assembly in mounted in mounted in th
RF
QUAL
The quali beginning of 2008 to Apri IPN Orsay c Aprilto Sept polluted the at the beginn have been pe The static expected from the helium d valve. A sec gas outlet flo copper therm natural temp nitrogen valv The RF co to 10 kW fir cooling down also observed a power hig pulsed mode lower than commissioni Amaximum reached, lim field emissio that polluted higher than th the pollution cavity to ab times higher nominal field The cavit frequency of a short per ted a second are in progres hat is not yet u ible dissipatio pure water. AS le because a l test in vertic A bellow of th d during hand On the third c oflex gasket c to about 1.10 reach the exc t only 2 cavit a cryomodu the qualificat he first cryomF POWER
LIFICATIO
ification cryo f year 2008 an il 2009. After clean room,it tember 2010.I cavity vacuum ning of the te erformed. cryogenic co m calculation decrease rate cond method ow at 300 K. T mal screen, perature incr ve. onditioning of rst with the c nthe cavity at d that no mult gher than 1 kW e was used fo 1 kW. The C ing from 1 to m acceleratin mited by a queon. This may d the cavity. T
he nominal va n of the cavity out 35 W at r than the spe d). ty was corr f 88.0525 MH riod of runn d time after ss to determin understood. S ons on the gas S5 cavity can eak appeared al cryostat. T he helium tank dling. This ca cavity AS9, a caused an inc 0-6 mbar. Fortu cellent maxim ties are compl ule: AZ1 and tion cryomodu module of the s
R TESTS OF
ON CRYO
omodule was nd it was teste a complete re was tested a In spite of a m of the qual ests period, al onsumption w . The measure after closing used the corr The heat load 25W, was d rease after c f the power coucavity at 300 t 4 K.It had b tipacting occu W. That is th or conditionin CW mode wa 10 kW. ng field of ench due to a have been c The maximum alue of 6.5 MV y increased th 6.5 MV/m;th ecifications (1 rectly tuned Hz. The cold t ning, becaus a new chem ne the cause o ome investiga sket, contamin nnot be mount on anNb/Nb The cavity nee k of the AZ6 c avity needs al small helium rease of the c unately it was mum field of a letely qualifie d AS13. AZ1 ule and AS13 series.
F THE
MODULE
s mounted a ed from Dece efurbishment i second time a serious leak lifying cryomo ll theforeseen was about 4.5 ement method the liquid he responding he on the cryomo determined by closing the lupler was mad 0 K and then een calculated urs in the coup he reason wh ng only at a p as applied fo f 7.8 MV/m an intense ele caused by the m gradient was V/m. Neverth he RF losses o his is more th 10 W maximu at the nom tuner blocked se the multi mical of the ations nation ted in weld eds to cavity lso to m leak cavity s still about ed for was 3 was t the ember in the from k that odule n tests W,as d used elium elium odule y the liquid de up after d and pler at y the power or the was ectron e leak s still eless, of the han 3 um at minal d after ilayer insul repai arise and relia runn could sensi back with of th to be frequ the meas A [8] h The respe field (spec woo The this s an ef Fi 400 contr acce Th and begin intro was RF p St sligh (4.5 work could frequ meas lation wrappe ir and proper e again, the tu short ranges ability over lo ning the moto d be observe itivity measu kslash is very h a high accur he helium bath e around 1 H uency adjustm frequency to sured to be 3.2 LLRF system has been succ
phase shift c ect to the RF d amplitude cifications: 1% fer fixed on th mode at 399 H system. The L fficiency of 29 gure 2: rejec Hz by the L rol – blue lerating field
RF POWE
CRYOM
he first cryom assembled in nning of year oducedin the c mounted in t power tests wa tatic cryogen htlyhigher th W) but lower ks as well as d be tuned wi uency of 88 sured with a ed around the modification uner worked c were perform ong periods. N or up to17.106 ed on any o ured was 0.1 small, and it w acy because o h that caused Hz, and it nev ment during t the liquid h 2 Hz/mbar; th m prototype de essfully tested could be mai F pilot (speci in the %).Microphon he vacuum ta Hz was the m LLRF system c 9 dB (see Figu ction of a m LLRF system curve: wit is 1.6 MV/mER TESTS
MODULE O
module of the s n the new insr 2011. Some cryogenic pipe this cryomodu as performed i nic load at an for the r than the spec s the qualific ith the require 8.0525 MHz. a better accur e screw of the ns avoiding th correctly. Cyc med in order No problem o 6 motor steps of the critica 4 Hz per mo was difficult to of the pressur frequency sh ver caused any
the tests.The helium bath he calculated w
eveloped for th d with the fre intained withi ifications: ±0 cavity with nics were ana ank in order to more easy to be could reject th ure 2). microphonics m (yellow cu th control).
during this tes
S OF THE F
OF THE SE
series was enti stallation at S e small modif
es circuits.The ule. The first in July 2011. t 4 K is a qualification cifications (7 W cation one, an ed accuracy a The backsla racy with a e tuner. After is problem to cles over long r to check its occurred after s. No damage al parts. The otor step.The o determine it re fluctuations hifts. It seems y problem of sensitivity of pressure was was the same.
he accelerator quency tuner. in ±0.1° with 0.5°), and the hin ±0.12% alysed using a o excite them. e excited with his mode with
pollution at urve: without The cavity st.
FIRST
ERIES
irely prepared Saclay at the fications were e AS13 cavity campaign of about 6.2 W, cryomodule W). The tuner nd the cavity at the nominal ash could be stable liquid r o g s r e e e t s s f f s r . h e % a . h h t t y d e e y f , e r y l e dProceedings of IPAC2011, San Sebastián, Spain MOPC079
07 Accelerator Technology T07 Superconducting RF 257 Copyright c○ 2011 by IP A C’11/EPS-A G — cc Cr eati v e Commons Attrib ution 3.0 (CC BY 3.0)
helium bath pressure, and is about 1 Hz. The tuning sensitivity is 0.12 Hz/motor step.
The RFconditioning of the power coupler could only be performed up to 5 kW because of redundant problems with the RF solid state amplifier. The maximum accelerating field before the quench of the cavitywas limited by field emission at5.9 MV/m(lower than the specification of 6.5 MV/m). At Eac c= 4 MV/m, no field
emission occurs, and the cavity dissipation measured by the increase of the outlet helium gas flow is about 2 W. This value is not accurate, but is close to the value measured during the RF vertical test of the cavity AS13. This confirms the fact that the major source of dissipation in the cavity at nominal accelerating field is electron field emission. The pollution source is not yet understood, but is possibly coming from the power coupler.
A second campaign of RF power tests will be performed in October in order to (try to)process the cavity and to increase the maximum accelerating field.
FUTURE PLAN
The general behaviours of the two first low beta cryomodules are quite similar.Very high RF dissipationsof the cavities are due to electron field emission, and limit the maximum accelerating at a value lower than the nominal field for one of the two tested cryomodules.Except the RF dissipations, all other points are within specifications and the cryomodules would be acceptable for operationin the machine.
Before going on with the assembling of the other cryomodules, we have to understand the sources of the
pollution. Analysis is in progressto determine the pollution levels due to dust particles of all the components connected to the cavity vacuum. The next test of a cryomodule A will be performed using a cavity equipped with a =1 incident power antenna (without any power coupler).
In parallel of the improvement of the cryomodules performances, investigations will be carried out to understand the source of the Q decrease observed on the latest tests of the cavities in vertical cryostat.
REFERENCES
[1] T. Junquera, P. Bertrand, R. Ferdinand, M. Jacquemet, "The high intensity superconducting Linac for the SPIRAL 2 project at GANIL", proc LINAC 2006, Knoxville, USA, p 142-144.
[2] P.-E. Bernaudin et al., “Testsstatus of the SPIRAL 2 low beta cryomodules”, PAC’09, Vancouver, May 2009, TU5PFP041.
[3] Y. Gómez Martínez et al, "theorical study and experimental result of the RF coupler prototypes of Spiral2", EPAC 06, Edinburgh, June 2006.
[4] G. Olry et al., “SPIRAL2 cryomodules: status and first results”, SRF09, Berlin, September 2009.
ACKNOWLEDGMENT
The author would like to thank IPN Orsay for their fruitful help during the assembling of the qualifying cryomodule in their clean room.
MOPC079 Proceedings of IPAC2011, San Sebastián, Spain
258 Copyright c○ 2011 by IP A C’11/EPS-A G — cc Cr eati v e Commons Attrib ution 3.0 (CC BY 3.0) 07 Accelerator Technology T07 Superconducting RF
