[Neutron] J-PARC Special News
masaarai at hotmail.co.jp
Wed Jan 24 16:51:25 CST 2007
J-PARC Project Newsletter
_______ January 23, 2007_______
Japan Proton Accelerator Research Complex under construction jointly
by the Japan Atomic Energy Agency (JAEA) and
the High Energy Accelerator Research Organization (KEK)
We are very pleased to inform you that at 0:54 am on January 24th
in Japanese time the J-PARC linac accelerated the H-minus beam
up to the energy of 181 MeV, which is the design value, and it will
be used for the injection to the J-PARC Rapid-Cycling Synchrotron
(RCS). The beam energy was measured by means of time-of-flight.
The peak current, the beam pulse length, and the repetition rate were
5 mA, 20 micro s and 2.5 Hz, respectively. These values were selected
for the purpose of the initial beam study, to avoid a possible damage
in accelerator components, if something wrong happened at a high beam
The J-PARC linac was ready for the acceleration up to 181 MeV at midnight
last Friday. Afterwards, an amplitude/phase scan for each pair of the
separated drift-tube linacs has been tried by using one klystron and,
finally, the scan through fifteen pairs were completed this week.
In each scan the beam energy was measured by the time-of-flight
During the beam commissioning, both RF power source and cavity
system have been very stable. This stability together with a very
accurate alignment of all the magnets, especially in the drift-tube linac,
were the two major elements to allow a rapid tuning of the linac.
We would like to thank all of you who have been supporting us.
The above result could be accomplished only by the help and the
contribution of all of you. On behalf of the J-PARC accelerator team,
we would like to express our sincere appreciation. In particular,
all workers, technicians, and engineers from industries, who have been
involved in manufacturing, construction and commissioning of the
J-PARC linac, are highly appreciated.
Thank you again,
Division Leader, Accelerator Division, J-PARC Center
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