SNS Linac experience 

1. ! quot; ##
$ % quot;

2. March 2000
Dec. 15, 1999
Sept.
2005
2 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

3. ORNL was responsible for integration,
installation, commissioning and
operation
Need a strong central team to take
intellectual ownership of the accelerator
3 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

4. 2003
2002 2004 2006
2005
Front-End DTL/CCL
SCL
DTL Tank 1
Ring
DTL Tanks 1-3
Target
• & quot;quot; ' quot; ' ( ' # ) & quot; *
quot; '( ' #) +,
•- quot; ) # ' ' & (
4 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

5. ! quot; # $%
1177 MW-hrs
Fluence (MW-hrs)
Power (kW)
480 MW-hrs
210 MW-hrs
127 MW-hrs
•. / ' ' ( ) ( ( %'
/ &
5 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

6. !$&
output
Ion Source
• 402.5 MHz
Radio-Frequency Quadrupole
• # 0/ & 1( / '2 (
•./ & # ( 3 45 ( ' 5
– *) ' ),
6 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

7. ' %
output
• 6 Tanks
•210 drift tubes
•PM quadrupoles
• 2.5 MW klystrons
(402.5 MHz), 1 per
tank
• Experience with PM quadrupoles is fine
• Minimal beam loss / activation observed
• Robust structure
7 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

8. output
• 4 modules
• 48 segments
•5 MW klystrons (805
MHz), 1 per module
CCL is also a robust structure
- Issues with RF induced gate-valve failures
Some beam loss near the CCL entrance and exit
8 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

9. % %
• 6- quot;#quot;
7
• 6- # 8
" (/
• %) ' quot; / (
Medium beta – 0.61
( '
•9 :
• & * ; <= ; ,
High beta – 0.81
• SCL is flexible
• Issues with accessories (HOM couplers, piezo tuners, …)
• Unexpected low level of beam loss
9 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

10. 10
Eacc (MV/m)
Eacc (MV/m)
0
0
2
2
4
4
6
6
8
8
10
10
12
12
14
14
16
16
18
18
1a 1a
•$
•9
•>
•6
1c 1c
2b 2b
(
3a 3a
3c 3c
&'
Aug_08
Aug_08
Managed by UT-Battelle
)
4b 4b
design
design
5a 5a
(
/(
(
for the U.S. Department of Energy
5c 5c
6b 6b
7a 7a
'
Nov_08
Nov_08
7c 7c
8b 8b
3 ?5
#quot;
9a 9a
9c 9c
)#@
'
10 10
bb
11 11
aa
11 11
cc
12 12
bb
12 12
dd
/
13 13
bb
quot; ( /quot; β
+ 25%
+ 25%
13 13
dd
'& '
14 14
bb
Presentation_name
14 14
dd
Cavity number
Cavity number
15 15
bb
/#quot;
*4 A
15 15
dd
16 16
bb
16 16
(
dd
17 17
bb
17 17
dd
'
18 18
bb
7,
18 18
dd
19 19
bb
#quot;
19 19
dd
20 20
bb
20 20
dd
'
21 21
bb
21 21
dd
β
22 22
bb
22 22
dd
23 23
bb
23 23
dd

11. quot;
•6 quot; 0/ '
“( ” •6
;5 ) & #quot; quot;
( (/ quot;
–B (quot; *quot; C quot; '
• # ,
' quot;
–6 /
' quot; ' '
' (
–9
30
No limits up to 22 MV/m
60 Hz collective limit
Individual limit or low rep rate collective limit (<20 Hz) in
25 closed loop
Lorentz force detuning
Individual limit or low rep rate collective limit (<20 Hz) in
open loop
Average Eacc (MV/m)
20
Quench (hard, Eacc<10 MV/m))
15
HOM
(1cavity disabled,
5 limited by large coupling)
10
Coupler Heating
5
Electron loading
0
(EG heating, gas burst, quench)
Medium beta cavity High beta cavity
0 10 20 30 40 50 60
No. of cavities
11 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

12. !$ %
402.5 MHz, 2.5 MW klystron
805 MHz, 5 MW klystron
DTL
RFQ CCL
805 MHz, 0.55 MW klystron
DTL Klystron
CCL Klystron
(6)
(1) (4)
Warm
Linac
86.8 MeV
2.5 MeV
SCL KlystronsMeV
1000
SRF, ß=0.81, 48 cavities
379 MeV
186 MeV SRF, ß=0.61, 33
cavities
SCL from
CCL
Linac
• Warm linac has 10 independently powered cavities
1 (81 total powered)
• SCL has 81 independently powered cavities
Many values to set w.r.t. the beam
A lot of Equipment to keep running!!!
12 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

13. ( % ) %
Longitudinal phase advance
•Each cavity has a
through 1st DTL tank
unique response
Different RF
(signature) to phase and
amplitudes
amplitude scans
TOF Change
•Phase scan signature
matching method uses
model to match
measurements and
determine RF amplitude
and phase setpoints
RF Cavity Phase
•- ' ( * ' /( , ( '& '
' //
• ' >B (quot; /( '
13 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

14. % ) %
Downstream Pickup
TOF
Black = measured
Red = sine fit
RF Phase
δβ
• quot; (quot; ' /( ( &
–6 ( >B ' A & /( ( >B ) quot;
•$ / '# &D
– &quot; /( # quot; @ quot; /quot; #' (
–B@ & >B /
14 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

15. % % !$ %
Arrival
Time:
Cavity:
• ( ( ( # '
() quot; >B / ( ' / quot;
>B quot; /( (E
–F ' ( ( quot;
–G/ & #quot;/ quot; >B '
• (/ quot; &
–% 6- )( # # &
' quot;quot; >B
15 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

16. * + $%
! + quot;
300 6
Phase Change
200 4
Measured Error
Measured Error (deg)
Phase Change (deg) 100
2
0
0
-100
-2
-200
-4
-300
-400 -6
1 7 13 19 25 31 37 43 49 55 61 67 73 79
Cavity
• ' ( / ( ##
quot; /( (/ (# # &) / (
•% #/ & quot; ) (1 2
•H ( ') ) 4( '
• Managed(by UT-Battelle
$ ' quot;
16
for the U.S. Department of Energy Presentation_name

17. * , %
-./
Consider this
part of the scan
•6 / ' /( # 6-
•F ' ' 0/ #quot;
(quot; / quot;
17 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

18. , % *
From Beam Loss
From Current
Transmission
•6 quot; / quot; #quot;
18 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

19. * 0
% -./
RMS Bunch Length
Halo tail ???
• quot; # / quot; '&
– / quot; ( quot; / * quot;,
– / quot;- * ( ,
19 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

20. Total Expected Beam Loss & Hottest
Expected Spot Meet Requirement
4
E xpected Total B eam Loss quot;H ot spotsquot;
100 Linacs, all errors 100 Linacs, all errors
3
w orst case
Beam Loss (W)
expected loss
Frequency
2
1
0
0 1 2 345 6 7 8 0 40 80 12 0 16 0 20 0
P tota l (W ) W (M eV )
20 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

21. ) %
25
DTL-CCL Transition CCL-SCL Transition
1 0 L in a cs , a ll e rro rs
20 + m is m a tc h
Beam Loss (W)
P m in
15 Pave
Pm ax
10
5
0
0 20 40 60 80 100 120 140 160 180 200
W (M e V )
21 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

22. )
• quot; quot; . %- E6 6 -
•$ quot; ( ( 6-
22 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

23. +
Residual activation @ 1ft after ~ 48h
Prompt radiation due to beam loss
Integral BLM dose [Rad]
Beam Loss monitor #
•
–
–
•
•!
– quot; ! #$ % &' quot; (
–) % (
–! quot; % (
23 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

24. 24
•-
Rad/C
Rad/C
• . ##
SC
L_
-50
0
50
100
150
200
250
SC Di a
0
50
100
150
200
g:
L_ B
D LM
SC i ag 00
)
L_ :B
LM
Di
Managed by UT-Battelle
01
SC ag
L_ :B L c
M
D
02
SC i ag
c
L_ :B
LM
Di
for the U.S. Department of Energy
03
SC ag
L_ :B L c
M
' /(
Di
04
SC ag
c
L_ :B
D LM
05
SC i ag
Beam Loss =
L_ :B L c
M
D
06
SC i ag
c
L_ :B
LM
Di
(
07
SC ag
c
L_ :B
LM
Di
08
ag
SC
L_ :B L c
1/24/08 300 kW
M
D
09
6/17/08 - 480 kW
SC i ag
c
)
L_ :B
12/15/08 - 650 kW
LM
Di
10
SC ag
L_ :B L c
M
Di
11
SC ag
c
L_ :B
LM
Di
13
ag
SC
Warm Section
L_ :B L b
M
D
14
SC i ag
c
L_ :B
SCL Loss
LM
BLM
SCL Beam Loss
Di
16
SC ag
L_ :B L b
M
Di
17
SC ag
c
L_ :B
D LM
19
SC i ag
L_ :B L b
Presentation_name
D M
20
SC i ag
L_ :B L c
M
D
22
SC i ag
beam loss signal
L_ :B L b
M
Di
+
23
SC ag
L_ :B L c
M
D
beam power on target
25
SC i ag
b
L_ :B
D LM
26
SC i ag
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76
dt
L_ :B L c
M
D
2
SC i ag
:B 8b
L_
LM
Di
29
SC ag
c
L_ :B
LM
Di
ag 31
b
:B
LM
32
c
1/6/2009
11/2/2008
12/15/2008
11/24/2008
10/13/2008
over 3 week run

25. ! % * + !%
Linac Activation
35 1400
3
30 days after run 1 1200
<SCL>
25 1000
3
mrem/hr
MW-hrs
20 800
charge
1
15 600
10 400
5 200
0 0
Ju 7
Ju 8
M6
D7
M7
D8
8
Se 7
Se 8
-0
-0
-0
0
0
-0
0
0
-0
p-
p-
n-
n-
ar
ar
ec
ec
ec
D
Run
•I ' quot; / # quot; quot; (
• 6- J ' # ) quot; ( '
25 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

26. Ring Foil Activation
Average SCL Residual Activation
summer 07
80
Avg. Warm Section Activation
600 summer 07 08
Winter
12 hr
70 Summer 08
500 winter 08
cooldown
Fall 08
60
spring 08
400
mRem/hr
50
mRem/hr
Fall 08
40
300
30
200
20
100
10
00
7
8
8
7
8
9
07
08
4/28/200 8/6/2007 11/14/20 2/22/200 6/1/2008 9/9/2008 12/18/20 3/28/200
00
00
00
00
00
00
20
20
/2
/2
/2
2
1/2
9/2
4/
8/
6/
8
2
8
7 07 8 08 9
8/
6/
9/
4/2
2/2
3/2
/1
/1
11
12
Run
Run
• 6- (/ /(/ 0/ & (/ ' / &
•6 > ' / (/ ) quot; (&
26 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

27. ! % * + $ quot;
'
Summer 2008
1.2
1
Relative Activation
SCL 2_3
SCL_12-13
0.8
SCL 16_17
0.6
SCL 32
0.4 Ring Foil
Ring A13b
0.2
0
0.00 5.00 10.00 15.00 20.00 25.00
Days after Production
• /'' # (1 quot; 2
• ' (( ' quot;quot; quot; / quot; ( #& quot;
quot;
• & quot; /' / 6- ) &quot; /
27 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

28. ) , %
10 nsec laser pulse,
2.0E-04
20 µsec beam pulse
BckGrnd
Single electron
Bump15
Laser laser stripping is
Laser15
1.5E-04
Enhanced
Beam Loss
used for profile
loss measurements in
1.0E-04
the SCL
5.0E-05
0.0E+00
b
12
16
20
24
28
32
00
a
04
08
M
ND
ND
ND
ND
ND
ND
M
M
BL
BL
BL
:
:
:
:
:
:
ag
ag
ag
ag
ag
ag
:
ag
:
:
Di
Di
Di
Di
Di
Di
ag
ag
Di
L_
L_
L_
L_
L_
L_
Di
Di
L_
SC
SC
SC
SC
SC
SC
L_
L_
SC
SC
SC
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(/ ' (/
•6 ) / quot; #quot; ( 3@ ) quot;
*L # # 4,
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E) quot;
• for the U.S. Department of Energy quot; ;,
quot; # # quot;Presentation_name
*K ) quot;
28 Managed by UT-Battelle

29. 1 ) quot; %
7
6
Beam Loss (E-4 Rad/pulse)
5
BLM03
BLM07
4
BLM10
Linear (BLM03)
Red= CCL4 vacuum 3 Linear (BLM07)
Linear (BLM10)
Others =2 SCL beam
loss
1
~ 3 hours
0
0 2 4 6 8 10
CCL Vacuum (E-7 Torr)
• 6- quot; 66-4 //quot;
•F quot; 6- '& #/ ( &' '
•B quot; 6- () quot; &) ##
• 66-4 //quot; ) #@ ( / '
29 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

30. •
30
/quot;
*
)
Managed by UT-Battelle
•H
quot;(
relative loss
–
relative loss
SC
–<
L_
– >B
for the U.S. Department of Energy '
– 9 ##
SSC Di a
'
CL g
L__ :B
quot;
SSC DDia L M
C L i agg 2
:
L__ :BB 0
i
/
00
0.50.5
11
1.51.5
22
2.52.5
SS DDaia LL M b
CC gg M22
L :
L__ :BB 10
(
'&
,
SS DDi LL M c b
a
CC i agg M22
L_ :B 31
L_ :
L
SS DDa BL M bc
CC i ig M2
#
#
L_ a:g: 2 3
quot;
L_ BL 4
SS DDa BL c b
CC i ig M2
quot;'
6
L_ a:g M2
_ BL 4
'
SC LDD :BL bc
SC i aig M2
L_ a:g M2 B7
)
_ i LM 6
SC LDDa :BL c b
SC ig: M
L a B 29
L L7
H _Di g:B M 2bc
/
E_
3
(
SBT Daig:B LM0
H CL_ ag L 2c
EB _D :B M 9b
H T_ Dia L 3 2
H EB D iag:B M3b
E 0
i g:
H BT T_ag BL M0 c
EB _ Di :B LM 2
quot; Presentation_name
H TD a gL 3 2
E ia M
H BT _D g: :BL05 b
EB _ ia B Ma
L
T_Dia g:B M 02
0
H D g: LM7
EB iag BL 0a
*N O
)%
SCL Beam Loss with Local Bumps
T_ :B M0 5a
D LM 9
;
ia
SCL Beam Loss with Local Bumps
g: 07a
BL
M
09
'P
,
8 mm Cav on
5 mm Cav on
8 mm Cav off
5 mm Cav off
V Bump 23
H Bump 23

31. 31
Normalized loss
SC
L_
D
•
SC iag
•6
L_ :BL
M
D
0
0.5
1
1.5
04
b
SC iag
:B
)
•- )
L_
Di LM0
5c
SC ag
L_ :BL
Managed by UT-Battelle
M
D 07
b
SC iag
:B
L_ LM
Di 08
##
c
SC ag
for the U.S. Department of Energy
(/
L_ :BL
M
Di 10
b
SC ag
quot;
L_ :BL
M
Di 11
c
SC ag
L_ :BL
M
Di 13 5% reductionquot;
b
SC ag
10% reduction
15% reductionquot;
L_ :BL
M
#'
Di 14
c
SC ag
L_ :BL
M
Di
#
16
b
SC ag
()
L_ :BL
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Di 17
c
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(
# ##
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BL
L_
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c
!
SC ag
:B
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D
quot;
22
b
SC iag
Quad Strength Sensitivity
L_ :BL
M
D
quot;'
23
'&
c
SC iag
L_ :BL
M
%
D
Presentation_name
25
b
SC iag
quot;
L_ :BL
M
D 26
c
SC iag
L_ :BL
M
D
quot;/
28
quot;Q
b
SC iag
:B
L_
Di LM2
9c
SC ag
L_ :BL
M
Di 31
ag
b
&%
:B
LM
32
c
along the SCL
quadrupole strength
Progressively reduce

32. 2% ! % 3!
•< ' 7 '6 (/ *< 7 6 , quot; #quot;
–6 .6 <= / #quot; / ' ( '&
•6 quot; #quot;
–$ ) '& quot; quot; @
32 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

33. quot;%
Beam Position vs. mini-pulse slower
slow
•. ' # ' '
–- %* ) ,L % *# ,
• % // L ) / ( /
–B / ( /quot; quot;
•- %
33 Managed by UT-Battelle
–H (( ( ) )( quot;
for the U.S. Department of Energy Presentation_name

34. %
•$R ?& / C
•I# 3& # 3? quot; ) 5
&
• quot; ' ) '
–quot; quot; # quot; (E ) ' A@
/
– ) # quot; ) ) (( @
quot; ( *& ,
•! ( quot; @ ) ' (
' ' / #/( ' ' quot;quot; '
( ' ' )
34 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

35. % quot;quot;
• ( ' / quot;quot; ' (
# ' ) 1' # (2
SNS: March 2000
It is possible
35 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

36. 4 +
Ring Injection Loss correlated with RFQ resonance error
RFQ resonance
error
3 kHz
Injection
Dump Loss
Few Watts Beam Loss
7 minutes
•@ / @ (
36 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name

37. *
Accumulator Ring
Collimators
Accumulator Ring:
1 GeV
Front-End:
Compress 1 msec
LINAC Injection Extraction
Produce a 1-msec
long pulse to 700
long, chopped, RF
nsec
H- beam
1000 MeV RTBT
2.5 MeV
HEBT
Front-End LINAC
Liquid Hg
Target
Chopper system
makes gaps
945 ns
mini-pulse
Current
Current
1 ms macropulse
1ms
1 ms macropulse
1 ms
37 Managed by UT-Battelle
for the U.S. Department of Energy Presentation_name