superc o nduc t ing 112 m hz q w r elec t ron g u n*f time and liq ellen t. hode rod was uple r...
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![Page 1: SUPERC O NDUC T ING 112 M HZ Q W R ELEC T RON G U N*f time and liq ellen t. hode rod was uple r (FPC) e cryomodul n in Figure 2 surrounded b, another laye metal). ycles: weldin nner](https://reader035.vdocuments.us/reader035/viewer/2022071501/612069c579e8f637f433e902/html5/thumbnails/1.jpg)
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S. Belome
Abstract Brookhaven
have designed quarter-wave cold test of thNiowave. Thepresents the cothe cryomodudifferent photocooling proof-options, one foone for a diam
A quarter-wRF (SRF) eleccooling hadronsufficiently cowavelengths). long electron effects and enshould be suitacurrent electro
A 112 MHzcold-tested in [3]. This is thsuccessfully. Infabrication, prplans. This guSRF gun to bhadrons in eRH
112
The cavity gFigure 1 showparameters, suappear nearly(recessed cathfocus the beamthe high intenshape has higbut these field
__________________________
* Work is supporContract No. DEBrook UniversityU.S. DOE. Workcontract No. DE-#sbelomestnykh@
SUPERCO
stnykh#,1, I. B. Sieg
1) Brook2) St
n National Laand fabricatedresonator (QWe QWR cryome paper descriold test results,ule. Future expocathodes and -of-principle exfor multi-alkali
mond-amplified
INTRODwave resonatorctron gun was n beams in RHompact even a
The long wabunches, thu
nabling high buable for experi
on beams. z QWR gun w
collaboration he lowest freqn this paper wresent the coldun will also serbe used for cHIC.
MHZ GUNFABRIC
geometry was ws the model usummarized in Ty electrostaticode, as shownm and compennsity electron her electric filevels are cont
__________________
rted by BrookhaveE-AC02-98CH108y is supported undk at Niowave is [email protected]
ONDUCT
Ben-Zvi1,2, Cgel3, J. Skaritkhaven Natiotony Brook
3) Niowa
aboratory and d a superconduWR) electron module has beeibes the cryom, and outline pperiments incluse for the co
xperiment. Twi photocathode photocathode,
DUCTION r concept of sproposed at BN
HIC [1, 2]. QWRat low RF freavelength allous minimizingunch charge. Aiments requirin
was designed, between BNL
quency SRF ge describe the
d test results, arve as a prototycoherent elect
N DESIGN ACATION designed usingsed to calculatTable 1. Sincec, a Pierce-t
n in the figure)nsate for the sbeam. The P
elds away frotrolled in the d
en Science Associa86 with the U.S. D
der grant DE-SC00pported by the U.S1
TING 112 M
C.H. Boulwtka1, R. Thanonal LaboratUniversity, Save, Inc., La
Niowave, Incucting 112 MH
gun. The firsen completed amodule design
plans to upgradlude studies ooherent electro
wo cathode stales and the othe, are discussed
superconductinNL for electroRs can be madequencies (lonows to producg space chargAlso, such gunng high averag
fabricated, anL and Niowavgun ever testegun design anand outline ouype for a futurron cooling o
AND
g Superfish [4]te the cavity RFe the fields witype geometr can be used t
space charge oPierce electrodm the cathode
design.
ates, LLC under DOE. Work at Ston005713 with the S. DOE under SBI
MHZ QW
are3, X. Chan1, M. Winotory, Upton, Stony Brook
ansing, MI 48
c. Hz
st at n, de of on lk er d.
ng n
de ng ce ge ns ge
nd ve ed nd ur re of
]. F ll
ry to of de e,
Table 1:
Paramet
Frequenc
R/Q (lina
Geometry
Quality f
Operating
Epk/Vacc
Epk/Ecath
Bpk/Vacc
Length
Aperture
Maximum
Figure 1:
Fig
ny
IR
WR ELECT
ang1, T.L. Grwski3, Q. WNY 11973-5
k, NY 117948906, U.S.A
RF parameter
ter
cy
ac definition)
y factor G
factor Q0 w/o cat
g temperature
m diameter
Cavity geome
gure 2: 112 MH
TRON GU
rimm3, X. LiWu1, T. Xin1,2
5000, U.S.A4, U.S.A. A.
rs of the 112 M
thode insert
etry used in Sup
Hz electron gun
UN*
iang1,2, T. Ra
A.
MHz SRF gun c
Value
112 MH
126 Ohm
38.2 Oh
> 3.51
4.5 K
19.1 m-1
2.63
36.4 mT
1.1 m
0.1 m
0.42 m
perfish calcula
n cryomodule.
ao1,
avity
Hz
m
hm
09
1
T/MV
ations.
Proceedings of SRF2011, Chicago, IL USA MOPO054
05 Cavity design 223
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F
The compleThe niobium cthe superinsulof superinsulat
Electron bethe niobium bconductor halvall niobium we
Figure 3: El
The stainlescavity prior to cooling jacket.pressure rinsecryomodule’s steel. The vessshield. Due tcryomodule wcarry out anassembly. Thecleanroom wipick-up probethe cryomoduchecked and co
The cooldosupply to theovernight witapproximatelyflanges to jusliquid nitrogenflanges were c130 K, with threaching 100 Khelium took pcooled at a ratthe time in thvessel sensor and the liquidsummary, the transition in apof the liquid cavity cooldowto boiling) was
For this testfundamental RFigure 4. An
te cryomodulecavity in a heation, liquid ntion, and magnam welding in
beam tube; weves; welding telding of the ca
lectron beam w
ss steel heliumchemical etch
. The cavity waed in the Cvacuum vesse
sel is demagneto the size of
was easier and n intermediate cavity was ith the cathode and beamlineule was compold shocked w
FIRST COown began we thermal shth exhaust gay 150 K. This t below 200 Kn pre-cool of tcooled at a ratehe temperatureK in about 2 hoplace after thte of 2 K/min fhe “Q diseasereached 4.4 K
d helium vesscavity was co
pproximately nitrogen pre-
wn (in terms os therefore exct, a copper catRF power coexternal (to th
e design is showlium vessel is nitrogen shieldnetic shield (muncluded four celding of the ithe subassembavity shown in
welded 112 MH
m vessel was whing of niobiumas chemically eClass 100 clel is made froetized and actsf this cavity, more efficient
te test beforhermetically
de assembly, pe vacuum complete, it was ith liquid nitro
OLD TEST with opening lhield. It was as from the s
procedure cooK. This was fothe helium vese of 10 K/min de monitors on tours. The switcat. The cavityfrom 130 K toe” range. The
K in approximsel was full inooled to the s3.5 hours from-cool. The effof time and liqcellent. thode rod wasoupler (FPC) he cryomodul
wn in Figure 2surrounded b
d, another layeu metal). cycles: weldininner and outebly; completinn Figure 3.
Hz Nb cavity.
welded onto thm and acted as etched and higleanroom. Thom low carbos as a magneti
testing in tht than trying tre cryomodul
sealed in thpower couple
mponents. Oncvacuum lea
ogen.
liquid nitrogecooled stabl
shield tubes aoled the cavit
followed by thssel. The cavitdown to arounthe vessel itselchover to liquiy flanges wero 10 K, limitine liquid helium
mately one houn 1.5 hours. I
superconductinm the beginninficiency of th
quid helium los
also used as as shown i
e) RF networ
2. y
er
ng er ng
he a
gh he n ic he to le he r,
ce ak
en ly at ty he ty nd lf id re ng m ur In ng ng he st
a in rk
was usedresonant observed The difficthe extremmode wa476.5 MHfundamenposition ocavity. Re
Figur
F
RF powof loadedbe easily Q of as hto the gaimposed 2 mrem/haround thcathode/cregion asconsistentsimulationQ at ~ 0.5cavity qufield emiQ degraconfidenc1.5 to 2.5helium bo
d for fine-tunimodes. The at 113.0 MHz
culty in locatinmely narrow bas also obserHz. The adjusntal mode wof the cathode esults are show
re 4: Testing se
Figure 5: Load
wer scans wered Q. The observ
conditioned awhigh as 109 waap voltage up
by the radhr, as there wahe cryomodule.coupler is inses shown in tht with the ns. Further, ve5 MV due to fi
uenches at highssion sites cou
adation at thce that this gun5 MV. The staoil-off, is less t
ing the couplfundamental
z within 2 houng the mode frandwidth of thrved at high stability of th
was measured and observing
wn in Figure 5.
etup for first cr
ded Q vs. catho
e performed atved multipactinway. As showns observed at to about 0.5
diation safetyas no dedicated. The cavity Q erted further
he lower curvone expecte
ery little degraield emission wh field were seuld potentially hese field len can perform atic heat leak, than 7 W
ling and searccavity mode
urs of the coolrequency was he mode. The “
Q and locathe coupling t
by changing the loaded Q
ryogenic RF tes
de position.
t two extreme vng barriers pron in Figure 6, fields correspoMV. The limi
y requiremend radiation shiis reduced whinto the high
ve. The reducted from comadation of the was observed aeen. Condition
eliminate all evels, giving
in the desired estimated fro
ch for e was ldown. due to “5λ/4” ted at to the g the of the
st.
values oved to
cavity onding it was
nts of ielding hen the h field tion is mputer cavity
and no ning of
cavity good range
om the
MOPO054 Proceedings of SRF2011, Chicago, IL USA
224 05 Cavity design
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F
P
un
F
vt
Figure 6: Cavcoupler in two
GThe near fu
gun will condiamond-amplit will be usedfor the coherenPoP) experimaforementionefollowing mod The low-c
with a stCode requ
The vacuuallow easy
A second Cryogenic
the BNL r Stainless
cryostat w Cathode s
designed diamond-
As the frequencypipe type
The FPC anused in the Nnew RF powerstalk assemblieFigure 7. The 100 kHz. Thexternal qualitdifferent CeCvoltage from 1to 3 nC at the b
vity Q vs. gao different posit
GUN MODuture experimencentrate on lified photocatd to produce hnt electron coo
ment at BNLed experimentsdifications: carbon-steel vatainless steel ouirements. um vessel willy access to insmagnetic shielc stack will brefrigeration systeel bellows
will be copper pstalks, inserts a
and fabricaamplified photCeC PoP e
y tuning, the nwill be also us
nd the cathode NPS prototype
r coupler / freqes for photocatfrequency tun
he FPC will ty factor from
C PoP operatin1 MV to 2 MVbunch repletion
ap voltage wittions.
IFICATIONents with the studies of m
thodes. Furtherhigh-charge eloling proof-of-
L [5]. To bes, the gun wi
acuum vessel wone to meet A
l have flanges ide of the cryold will be adde
be modified toystem. and beam tuplated to reducand a load lockated for mutocathodes. experiment rnew FPC of ased for tuning. stalks will be 500 MHz SRF
quency tuner athodes are bein
ner will have raprovide adjus
m 3107 to 1.2ng conditions
V and bunch chn frequency of
th the cathode
N 112 MHz SRF
multi-alkali anr down the linlectron bunchef-principle (CeCe used in thill undergo th
will be replaceASME Pressur
on both ends tostat. ed. o interface wit
ubes inside thce RF losses. k system will bulti-alkali an
equires cavita coaxial beam
similar to thosF gun [6]. Thand the cathodng designed [7]ange of at leasstability of th2108 to cove
with the gaharge from 1 nCf 78 kHz.
e/
F nd ne es C
he he
ed re
to
th
he
be nd
ty m
se he de ], st
he er ap C
Figure 7:and FPC.
We ha112 MHzThe gunperformanThe obseThere wavoltage osafety req
We plphotocathelectron c
[1] A. Fefor LAcce
[2] A. FeRHICChin
[3] S. Beof BElectPAC
[4] K. HCompCylin(1976
[5] G. WFEL-of PA
[6] S. P. 500 MFEL2
[7] T. XiCoupSupeMOP
SRF gun cryo
SUave successfulz SRF gun ban cryomodulence. RF losserved multipactas no cavity of ~ 0.5 MV wquirements. an to use th
hodes and procooling proof-o
REFedotov, et al., Low-Energy Relerator AP Noedotov, et al., “C Program,” Pa, MOM2MCIelomestnykh, eBNL Supercotron Gun A’2011, TUP051albach and Rputer Programndrical Symm6) 213-222.
Wang, et al., “P-based Coheren
AC’2011, THOBNiles, et al.,
MHz Quater-W2010, WEPB28in, et al., “Depler and Photoerconducting EPO014.
module with th
UMMARY lly designed aased on a quare demonstrates are consistenting barriers wquenches and
was limited on
his SRF gun ovide electronof-principle exp
FERENCES“Feasibility o
RHIC Operatioote C-A/AP/30“Electron Cool
Proceedings of IO01, p. 11 (20et al., “Design onducting 112Applications,”1 (2011).
R.F. Holsinger, m for Evaluationmetry,” Partic
Proof-of-Princnt Electron CoBN3 (2011). “NPS Prototy
Wave Gun Upd8 (2010). esign of the Focathode InserElectron Gun
he new cathode
and cold-testerter-wave reso
ed good cryont with simula
were easy to prd the achievenly by the rad
to study difns for the coperiment at BN
S of Electron Con,” BNL Co7(April 2008).ling for Low-E
f COOL09, Lan009).
and First Col2 MHz QWR Proceeding
“SUPERFISHn of Rf Cavitiecle Accelerato
iple Experimeooling,” Procee
ype Superconddate,” Proceedi
Fundamental Prts for the 112,” this confe
e stalk
ed the onator. ogenic ations. rocess. d gap diation
fferent oherent NL.
ooling ollider-
Energy nzhou,
ld Test R for
gs of
H – A es with ors 7
ent for edings
ducting ings of
Power 2 MHz erence,
Proceedings of SRF2011, Chicago, IL USA MOPO054
05 Cavity design 225