Review of SC spokes cavities for low-medium energy. Evgeny Zaplatin (FZ Jülich)

2. !quot; # %%&
$
'( )* (+ !quot; , , - . quot;/ ) quot; $%%&
01 -) 0 2 - !quot; , , - . quot;/ ) quot; $%%&
01 0 2 / ) !quot; , , - . quot;/ ) quot; $%%&
Low-beta SC Nb Community
Juelich
Spoke
Community
2

3. ) 6
* 2
*
78 $ . ' 9
βλ / 2 A A
β: % 78
: $8 1.0
βλ;$ : <=>
0.8
Ez / Ez max
0.6
0.4
9? :% 7@βλ;$ 0.2
0.0
0 20 40 60 80 100 120 140
z / mm
z_spoke
)
3 5
3' 4 5
3

4. )
B : 78 $ . ' 9
β↑
β↓
↑
↓
↓
↑
↑
↓ 9↑
)↓ β : % 78
β : % <8
β : % 88
B
) 3<C D . ' 95
10
250 14
spoke
9
240
cavity radius/length [mm]
12 hwr
B_pk / E_acc [mT/MV/m]
230 8
10
220 7
E_pk / E_acc
210 6
8
200 5
6
190 4
spoke
180 3
hwr
4 spoke
170 2
hwr
2
160 1
150 0
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0 0.1 0.2 0.3 0.4 0.5 0.6
0 0.1 0.2 0.3 0.4 0.5 0.6
beta = v/c beta = v/c
beta = v/c
4

5. A F
+ A
quot;A
→
A
)
E quot; quot;0 / - >$
5

6. A
# $ !
GE
!quot;
F
quot;
/0
6

7. A F
F
quot;
A F
3$ 75
GE
1
F
A
)
/0
$ quot; quot;
7

8. A
)
)
) <=
,)
)
quot;
)
)
,)
F
A quot;A
8

9. tsr
ssr
760MHz ssr
345MHz
β=0.2 345MHz
β=0.4 tsr
FZJ β=0.3
345MHz
ANL
hwr hwr ANL
β=0.5
176MHz 176MHz
ANL
hwr β=0.11 β=0.16
176MHz FZJ ACCEL hwr tsr
β=0.09 172.5MHz 345MHz
ACCEL β=0.26 β=0.64
tsr
ANL ANL
352MHz
ssr
dsr
β=0.3
ssr 855MHz
345MHz
IPN
350MHz β=0.5
β=0.4
β=0.175 ANL
ANL
LANL
hwr hwr
176MHz 322MHz
β=0.15 β=0.28
Legnaro MSU tsr
hwr hwr
325MHz
175MHz 175MHz ssr β=0.62
β=0.094 β=0.166 352MHz Fermilab
IFMIF IFMIF β=0.35
IPN
ssr
325MHz
β=0.22
tsr
hwr Fermilab ssr
ch ssr 352MHz
355MHz 325MHz
360MHz
β=0.12 352MHz β=0.48
β=0.4
β=0.1 β=0.15 FZJ
ANL Fermilab
FrUni IPN
β = v/c
9

10. ) ) 6
H-cavity
V. V. Vladimirsky, 1956
P. Blewett, 1956
19-gap CH 360MHz β=0.1 7-gap CH 325 MHz β=0.15,
Frankfurt Uni, 2007
FraUni, 2005
Vertical test: 7 MV/m
clean problems!
10-gap multi-spoke 700 MHz β=0.2, Juelich, 1999
10

11. A
B : 78 $ . ' 9
β : % <& β : % =& β : % >&
14 7 β:<
A+
12 6
Bpk / Eacc [mT/MV/m]
A ) A
10 5
B +
Epk / Eac
8 4
270
6 3
250
4 2
Bpk/Eacc 230
rcav [mm]
Epk/Eacc 210
2 1
190
0 0 170
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 150
beta = v/c 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
beta = v/c
11

12. )
80
14
4K
70
2K
12
60
10
Epk [MV/m]
50
Eacc [MV/m]
8 40
6 30
20
4
4K
10 2K
2 tesla @ Eacc=30
0
0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
beta = v/c
0 :3 A 1 beta = v/c
A 1 A 5;$
160
140
120
) )
100
Bpk [mT]
A )
) 80
A
60
40
4K
20 2K
tesla @ Eacc=30
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
beta = v/c
12

13. tsr 345 MHz
ssr 325 MHz
β=0.5-0.64
β=0.22
ANL
Fermilab
<5 , ) $ A ) ) )
<% % ) ) <8 % *(
) 3, :7% -quot; K <$ <& K quot; 7%
; $ quot; & 8 H<% H) 5
5) ) A ) )
' (* ) ) ,) )
37% % 7 5 A L7 A ) A <$
*( ) ) ) ' (*
,) ) L8 % C 8
5 /0 <8 % H
A)
A5 ) ) ) ) ) 2-( ) ' H' / 7H' 7( <H<H$ 1* ) C% >%
=
A ) ) ) ,) 2 A quot; ) )
) A ) M M) + )A 3/ A I <% ; 5 <8 > -
) ) <= > - <C - ) 4 ) <<>
5 '( ) *(N A A )
) )
A5 ' ( /0- <% <8 % H
5 <% 2-( )
3 ) * OM ) *(M5 H 99 )D + quot; ) J=8 quot; > % =8
5, ) ) )) ) ) ) ) 3$ A J7 1 4 A 1 13
5 L< ) ) L<% % A 99 <8 ) 5 A 7 ; E ) D
P) A $% ) -
) ) $ ) 3 5 - <% )
M. Kelly, Jan., 2009 R.Wagner, HB2008
) 3 quot; 2A 5
13

14. ssr 352 MHz tsr 760 MHz
β=0.35 β=0.2 FZJ
Jlab test
IPN Orsay
1.E+10
FE
M ultipacting
1.E+09
Q0
test 2 (T=2 K)
test 2 (T=4.2 K)
test 1 (T=2 K)
test 1 (T=4.2 K)
1.E+08
0 2 4 6 8 10 12 14
Eacc [MV/m]
2-( -* $%%$H ) ) After test 1 the cavity was warmed up, disassembled, degreased and heat
A) treated at 600 C for 10 hrs. After furnace treatment, degreased and bcp
A, with 1:1:3 in steps of 5 min each ( on sample app. 0.9 microns/min); total
H ) A <8 % Q time of bcp 30 min; then HPR in 2 locations axially with cavity rotating,
app. 30 min each, R@D hpr system. Cavity dried in class 10 clean room
'( $%%$ -* ; H
over night and assembled next morning (PK); attached to test stand and
) )A HA =8 <);A (
evacuated; prior to cooldown, p~ 1.2e-8 mbar, cont'd next day after
& % ;<% %
Helium top off. P. Kneisel, Feb., 2008
G. Olry, HIPPI Meeting, Sept., 2004
A
14

15. ) A 6
C % = . ' 9quot; β : % =C quot; / /
C % = . ' 9quot; β : % =C quot; -* 78 $ . ' 9quot; β : % =& quot; G E
stiffening rings
0
0
1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
-10
-200
-20
-400
K_L [Hz/(MV/m)**2]
K_V [Hz/mbar]
-30
-600
fzj tsr
-40
-800
infn
fzj tsr
saclay one.ring
infn
saclay tw o.rings
-50
-1000 saclay one.ring
saclay tw o.rings
-60
-1200
K_ext [N/m m ]
K_ext [N/m m ]
15

16. A
) ;
1A ;
3
quot;
5
2 A
2 *
A A
2 *
A A
tuning in
max b-
field
16

17. )) A
15 0.0
1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
10
-1.0
tsr.0.98_lhe.vessel
5
tsr.0.48_lhe.vessel
-2.0
K_L [Hz/(MV/m)**2]
0
K_V [Hz/mbar]
1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07
-5 -3.0
-10 tsr.0.98_lhe.vessel
-4.0
tsr.0.48_lhe.vessel
tsr.0.98_no.lhe.vessel
-15
tsr.0.48_no.lhe.vessel
-5.0
-20
-25 -6.0
K_ext [N/m m] K_ext [N/m m ]
external pressure deformations lorenz forces deformations
17

18. * - A -, - quot; -0 (. !quot; ' ((
. quot; $D $C A quot; $ % % C quot; (/ F 0 / -=quot; > % <D % . K
- - C%= = . ' 9 →) ) )
3J5 ) ) B
3J5
3 5A A
35 ) B )
( 78 $ $ . ' 9
3J5 )
3J5
3J5 B )
35 )
9 L% 8 λ 3L% > λ 5→
3J5 ,. )
-, - 78 $ $ . ' 9
→
9) B
→A →+
3J5 = ;
> % <D % . K
3J5 B )
35 1
18