Abstracts Brochure - CERN

THPPA — Prize Presentations 29-Jun-06 14:00 - 15:30
THPPA — Prize Presentations
High-Gradient Superconducting Radiofrequency Cavities for Particle Acceleration
The development of radiofrequency superconductivity
for particle acceleration has L. Lilje (DESY)
reached a level where many projects consider
its use. One of the many attractive features of these accelerating structures is to achieve very high accelerating fields
efficiently. The technology has been developped to a stage where accelerating gradients of more than 25 MV/m
are being implemented in accelerator modules. In single-cell test resonators even higher gradients were already
achieved. To operate cavities at these gradients efficiently their frequency needs to be kept stable to reduce the need
for an overhead in radiofrequency power. Introducing active elements like piezoelectric actuators allows to achieve
these goals.
The First CW Accelerator in USSR and a Birth of Accelerating Field Focussing
As CW linear accelerators became required,
it appeared an absolute necessity to change V.A. Teplyakov (IHEP Protvino) R.A. Jameson (IAP)
the initial part of the accelerator. The initial
part should prepare bunches of charged particles for the further acceleration in the main part. The CW accelerator
should also be economic and reliable. The problem was solved using the principles of adiabatic capture of particles
and low energy injection with focusing by means of the RF field. The acceleration of bunches with non-increasing
charge density was the basic idea. It allowed reduction of the injection energy without reducing the current. By 1972,
initial testing in IHEP Protvino was accomplished, and the first accelerated beam was obtained in an RFQ. The URAL-
30 proton linac was commissioned in 1977 in IHEP. It applies RFQ-focusing from injection up to the top energy of 30
MeV. From 1985 until the present, this facility routinely operates as an injector to a booster proton synchrotron, this
feeding the entire accelerator complex of ITEP. Development of the first RFQ in the Western world was started at Los
Alamos in 1978 and performed a proof-of-principle test in 1980. After that there were many articles and reports and
the RFQ became widely known in the world.
Chair: N. Angert (GSI, Darmstadt) 379
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