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February
19, 2007:
SNS Design Energy of 1 GeV Reached
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SNS superconducting linac. This section operates in conjunction with
the room-temperature drift-tube and coupled-cavity linacs.
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On February 19, 2007, the SNS
accelerator systems accelerated
beam to
1.01 GeV, a new world energy
record for proton beam acceleration
in a linear accelerator (linac).
This success breaks the previous
record of 0.95 GeV, which SNS
achieved in December 2005, and
achieves the intended design
energy of 1.0 GeV. The increase
in beam energy was made possible
by a better understanding of
the performance capabilities
and margins of the linac's superconducting
cavities, which provide the bulk
of the acceleration. The ultimate
pulsed beam power delivered by
the SNS accelerator increases
by almost an order of magnitude
compared with existing neutron
facilities.
The SNS accelerator system consists
of
- a negative hydrogen (H-)
radio-frequency volume source,
- a low-energy
beam transport housing a first-stage
beam chopper,
- a 4-vane radio-frequency
quadrupole for acceleration
up to 2.5 MeV,
- a medium-energy
beam transport housing and
a second-stage chopper,
- a 6-tank
drift-tube linac up to 87 MeV,
- a 4-module coupled-cavity
linac up to 186 MeV, and
- a
superconducting linac with
11 medium-beta cryomodules
(up to 379 MeV) and 12 high-beta
cryomodules (up to 1000 MeV).
The linac produces a 1-ms-long,
38-mA peak, chopped beam pulse
at 60 Hz for accumulation in
the ring. A high-energy beam
transport line provides for
diagnostics and collimation
after the linac injects into
a 248-m-circumference accumulator
ring to compress the 1-ms pulse
to ~700 ns for delivery onto
the target through a ring-to-target
beam transport beam line. Neutrons
are produced by spallation
in the target, dumping 27 kJ
per pulse into ~1 m3 of
circulating mercury. The neutron
energy is then moderated to
useable levels by supercritical
hydrogen and water moderators
before feeding into 24 beam
lines.
April 28, 2006: SNS Successfully
Commissioned
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Data from
the successful
SNS commissioning
run on April 28,
2006.
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After a frustrating morning of technical problems, at 2:04 p.m., an accelerated proton beam hit the SNS target. A phosphor screen attached to the front of the mercury target flashed, showing clearly that the proton beam was on target. Simultaneously, instruments in the Target Building recorded the first burst of neutrons.
The official commissioning
goal of a pulse of 1013 protons
on target was reached 90 minutes
after the initial beam on target,
a feat that was expected to take
several weeks to achieve. Having
now completed this key technical
milestone, SNS is now officially
a neutron source.
More about the SNS commissioning:
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