Commissioning Results, First

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15 Νοε 2013 (πριν από 3 χρόνια και 7 μήνες)

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Spallation Neutron Source Project:
Commissioning Results, First
Operation Experience, and Upgrade
Plans


Alexander Aleksandrov


Oak Ridge National Laboratory

Oak Ridge, USA

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Neutron scattering

Neutrons probe a broad range of length scales

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Fission



chain reaction



continuous flow



1 neutron/fission




Spallation


no chain reaction


pulsed operation


30 neutrons/proton


Time resolved exp.



Spallation
-
Evaporation Production of Neutrons

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk




The SNS began
operation in 2006


At 1.4 MW it will be

~7x ISIS, the world’s
leading pulsed
spallation source


The peak neutron flux
will be ~20
-
100x ILL


SNS will be the world’s
leading facility for
neutron scattering


It will be a short drive
from HFIR, a reactor
source with a flux
comparable to the ILL

The Spallation Neutron Source

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

The Spallation Neutron Source Partnership

~177 M$


~60 M$

~113 M$

~20 M$

Description
Accelerator
Project Support
75.6
Front End Systems
20.8
20.8
Linac Systems
315.9
315.9
Ring & Transfer Systems
142.0
142.0
Target Systems
108.2
Instrument Systems
63.3
Conventional Facilities
378.9
Integrated Control Systems
59.7
59.7
BAC
1,164.4
Contingency
28.3
TEC
1,192.7
R&D
100.0
80.0
Pre-Operations
119.0
95.2
TPC
1,411.7
713.6
~63 M$

~106 M$

SNS
-
ORNL Accelerator systems:

~167 M$

At peak : ~500 People

worked on the
construction

of the SNS accelerator

Oak Ridge, TN

35
°

49' N , 83
°

59' W

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Spring 1999

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Spring 2000

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Spring 2001

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Spring 2002

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Spring 2003

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Spring 2006

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

SNS Accelerator Complex

945 ns

1 ms macropulse

Current

mini
-
pulse

H
-

stripped
to protons

Current

1ms

Front
-
End:
Produce a 1
-
msec long,
chopped,
low
-
energy
H
-

beam

LINAC:
Accelerate
the beam to
1 GeV

Accumulator Ring:
Compress 1 msec
long pulse to 700
nsec

Deliver
beam to
Target

Chopper
system makes
gaps

Ion Source

2.5 MeV

1000 MeV

86.8 MeV

CCL

SRF,
b
=0.61

SRF,
b
=0.81

186 MeV

387 MeV

DTL

RFQ

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

The SNS Target: 2
-
MW Design


Cavitation
-
induced pitting is an issue.


Options for mitigation:


Materials, Geometry


25 kJ/pulse at 7x15cm beam size sets of
transverse and longitudinal shock wave.


Needs to be exchanged every 3 month

1 mm

Pits on inner surface
in this geometry

17 Instruments Now Formally Approved


Fundamental Physics to
Engineering


Chemistry to “Genomes to
Life”

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

The SNS Main Parameters

1.107
1.098
1.058
Ring rf frequency [MHz]
0.2
0.15
0.15
Ring space
-
charge tune spread,

Q
sc
683
691
695
Pulse length on target [ns]
70
70
68
Chopper beam
-
on duty factor [%]
6.0
6.0
6.0
Linac beam macro pulse duty factor [%]
65
42
26
Average
macropulse
H
-
current [mA]
92
59
38
Peak Current from front end system
3.9
2.5
1.6
Linac average beam current [mA]
5.0
3.0
1.4
Beam power on target,
P
max
[MW]
12 + 8 (+1 reserve)
12 + 8 (+1 reserve)
12
SRF
cryo
-
module number (high
-
beta)
1.6
1.0 / 1060
35 (+2.5/
-
7.5)
27.5 (+/
-
2.5)
33+48
11
1000
Baseline
2.5
1.0 / 1100
31
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1300
Upgrade
3.8
1.0 / 1110
34
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1400
Ultimate
Ring bunch intensity [10
14
]
Ring injection time [ms] / turns
Kinetic energy,
E
k
[MeV]
Peak gradient,
E
p
(
b
=0.81 cavity) [MV/m]
Peak gradient,
E
p
(
b
=0.61 cavity) [MV/m]
Number of SRF cavities
SRF
cryo
-
module number (med
-
beta)
1.107
1.098
1.058
Ring rf frequency [MHz]
0.2
0.15
0.15
Ring space
-
charge tune spread,

Q
sc
683
691
695
Pulse length on target [ns]
70
70
68
Chopper beam
-
on duty factor [%]
6.0
6.0
6.0
Linac beam macro pulse duty factor [%]
65
42
26
Average
macropulse
H
-
current [mA]
92
59
38
Peak Current from front end system
3.9
2.5
1.6
Linac average beam current [mA]
5.0
3.0
1.4
Beam power on target,
P
max
[MW]
12 + 8 (+1 reserve)
12 + 8 (+1 reserve)
12
SRF
cryo
-
module number (high
-
beta)
1.6
1.0 / 1060
35 (+2.5/
-
7.5)
27.5 (+/
-
2.5)
33+48
11
1000
Baseline
2.5
1.0 / 1100
31
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1300
Upgrade
3.8
1.0 / 1110
34
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1400
Ultimate
Ring bunch intensity [10
14
]
Ring injection time [ms] / turns
Kinetic energy,
E
k
[MeV]
Peak gradient,
E
p
(
b
=0.81 cavity) [MV/m]
Peak gradient,
E
p
(
b
=0.61 cavity) [MV/m]
Number of SRF cavities
SRF
cryo
-
module number (med
-
beta)
A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk


65 kV, 45 mA H
-

ion
source


Electrostatic LEBT
with pre
-
chopper


2.5 MeV 402.5 MHZ
RFQ



3.6 m long MEBT
with chopper and
beam diagnostics

Front End (injector)

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

402.5 MHz

Drift Tube Linac (DTL)



DTL accelerates beam to 87 MeV



System includes 210 drift tubes in
six separate tanks (37m total
length)



Inside drift tubes: permanent
magnet quadrupoles,
electromagnetic dipole correctors,
strip
-
line beam position monitors
(BPM)

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Drift Tube Linac in the tunnel

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

805 MHz Coupled
-
Cavity Linac (side coupled)



CCL accelerates beam to 187 MeV



System consists of 48 accelerating segments, 48 quadrupoles,
32 steering magnets and diagnostics (55 m total length)


Bridge Coupler 44 final machining

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Coupled
-
Cavity Linac in the tunnel

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

805MHz Super Conducting RF Linac (SCL)



SCL accelerates beam from 187 to 1000 MeV


81 6
-
cell superconducting cavities in 23 cryo
-
modules (157m)


Cavities are operated at 2.1K or 4.2K


Two cavities geometries are used to cover broad range in particle
velocities


Cavities are assembled
into strings


Medium beta cavity

High beta cavity

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

S
uperconducting Cavity Performance

Nr of Cavities

Nr of Cavities

High Beta
0
2
4
6
8
10
12
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
E0 (MV/m)
Frequency
Medium Beta
0
1
2
3
4
5
6
7
0
2
4
6
8
10
12
14
16
18
20
22
24
E
0
(MV/m)
Frequency
A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Super Conducting Linac in the Tunnel

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk


High
-
Power RF Systems


Compact High Voltage Converter
Modulators using solid state devices
(IGBT)


High
-
Power RF System: klystrons,
waveguides, circulators


7 402.5 MHz 2.5 MW klystrons


4 CCL 5 MW Klystrons


81 SCL 550 kW klystrons


A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Cavity field and phase droop with
feedback alone (left) and feedback
+ feedforward (right) beam loading
compensation.

Phase width of the bunch along the pulse
with feedback alone (left) and feedback +
feedforward (right)

Digital Low Level RF system

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

SNS Central Helium Liquefying Facility


Cold box
specifications are:


8300 Watts on the
shield


2400 Watts @
2.1Kelvin


15g/s Liquefaction

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Circumference


248 m

Energy


1 GeV

Revolution period 1
μ
s


Number of turns


1060

Final Intensity


1.5x10
14

Peak Current


52 A

Number of magnets >300

(bend and focusing)

The SNS Accumulator Ring

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Ring Installation Progress

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

SNS Liquid Mercury Target

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

SNS Remote Handling Manipulators

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

Commissioning Timeline

2002

2003

2004

2005

2006

DTL Tanks 1
-
3

Front
-
End

DTL Tank 1

DTL/CCL

SCL

Ring

Target

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

5x10
13
/pulse Protons Delivered to the Target

Final RTBT Beam
Current Monitor

Ring Beam Current
Monitor

Beam on Target
View Screen

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

1st “Production Run”


A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk



Transition to Operation

0
500
1000
1500
2000
2500
0
12
24
36
Months
Beam Power (kW), Production Hrs
50
55
60
65
70
75
80
85
90
95
Reliability
Beam Power Goal
Neutron Production Hours
Reliability
0
500
1000
1500
2000
2500
0
12
24
36
Months
Beam Power (kW), Production Hrs
50
55
60
65
70
75
80
85
90
95
Reliability
Beam Power Goal
Neutron Production Hours
Reliability
FY08

FY07

FY09

A. Aleksandrov RuPAC 2006 Sept. 10


14, 2006

Novosibirsk

The SNS Power Upgrade Main Parameters

1.107
1.098
1.058
Ring rf frequency [MHz]
0.2
0.15
0.15
Ring space
-
charge tune spread,

Q
sc
683
691
695
Pulse length on target [ns]
70
70
68
Chopper beam
-
on duty factor [%]
6.0
6.0
6.0
Linac beam macro pulse duty factor [%]
65
42
26
Average
macropulse
H
-
current [mA]
92
59
38
Peak Current from front end system
3.9
2.5
1.6
Linac average beam current [mA]
5.0
3.0
1.4
Beam power on target,
P
max
[MW]
12 + 8 (+1 reserve)
12 + 8 (+1 reserve)
12
SRF
cryo
-
module number (high
-
beta)
1.6
1.0 / 1060
35 (+2.5/
-
7.5)
27.5 (+/
-
2.5)
33+48
11
1000
Baseline
2.5
1.0 / 1100
31
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1300
Upgrade
3.8
1.0 / 1110
34
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1400
Ultimate
Ring bunch intensity [10
14
]
Ring injection time [ms] / turns
Kinetic energy,
E
k
[MeV]
Peak gradient,
E
p
(
b
=0.81 cavity) [MV/m]
Peak gradient,
E
p
(
b
=0.61 cavity) [MV/m]
Number of SRF cavities
SRF
cryo
-
module number (med
-
beta)
1.107
1.098
1.058
Ring rf frequency [MHz]
0.2
0.15
0.15
Ring space
-
charge tune spread,

Q
sc
683
691
695
Pulse length on target [ns]
70
70
68
Chopper beam
-
on duty factor [%]
6.0
6.0
6.0
Linac beam macro pulse duty factor [%]
65
42
26
Average
macropulse
H
-
current [mA]
92
59
38
Peak Current from front end system
3.9
2.5
1.6
Linac average beam current [mA]
5.0
3.0
1.4
Beam power on target,
P
max
[MW]
12 + 8 (+1 reserve)
12 + 8 (+1 reserve)
12
SRF
cryo
-
module number (high
-
beta)
1.6
1.0 / 1060
35 (+2.5/
-
7.5)
27.5 (+/
-
2.5)
33+48
11
1000
Baseline
2.5
1.0 / 1100
31
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1300
Upgrade
3.8
1.0 / 1110
34
27.5 (+/
-
2.5)
33+80 (+4 reserve)
11
1400
Ultimate
Ring bunch intensity [10
14
]
Ring injection time [ms] / turns
Kinetic energy,
E
k
[MeV]
Peak gradient,
E
p
(
b
=0.81 cavity) [MV/m]
Peak gradient,
E
p
(
b
=0.61 cavity) [MV/m]
Number of SRF cavities
SRF
cryo
-
module number (med
-
beta)