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Accelerators 2017
Highlights an Annual Report
Dear Colleagues and Friends of DESY,
The year 2017 was a year of truly outstanding achievements
at DESY as one of the world’s leading accelerator centres,
especially regarding the European XFEL X-ray laser project.
The beam commissioning of the European XFEL accelerator
complex, the demonstration of first hard X-ray free-electron
laser (FEL) radiation and the provision of first photon beams
to users are the most prominent highlights of this remarkably
successful period.
In 2016, the completion of the European XFEL accelerator
construction, the beginning of its technical commissioning
and the successful beam commissioning of the injector had
laid the foundation for the progress that was to follow in
2017. The sections of the superconducting linear accelerator
were successively put into operation, and by April 2017, most
of the radio frequency (RF) sections were active and the
electron beam had reached the beam dump after the accelerator
tunnel. Transport of the beam through the first undulator
line (SASE1) was then quickly established, and after steering
optimisation, a clear FEL radiation signal was observed for
the first time on 2 May. The first lasing was an unplanned, but
most welcome timely match with the concluding meeting of
the DESY-led Accelerator Consortium on 4 May at DESY. At
that event, the 17 institutes involved in the construction of the
accelerator complex reviewed their joint work of the past
seven years and celebrated the completion of their mission.
All involved DESY staff members together with their
colleagues from the collaborating institutes could look with
pride and satisfaction on the achievements in one of the
largest and most challenging projects in the history of DESY.
During the following months, the beam parameters were
further improved, and a photon beam wavelength of 0.13 nm
and a pulse energy of up to about 1 mJ were reached, both
already close to the European XFEL specification. An electron beam energy of 14.9 GeV was achieved with two RF stations
still inactive, which are to be commissioned in 2018. Ramping
up the beam intensity has to be done with care to minimise
radiation damage risk, and in this initial phase, FEL operation
was limited to 30 bunches per accelerator pulse. In machine
studies, however, operation with 300 bunches (3 kHz average
bunch rate) was already successfully demonstrated. The
rapid progress of the beam commissioning was achieved
thanks to reliable and well-performing subsystems, including
diagnostics and controls, and thanks to the strongly committed
and competent operations team. Last but not least, the
very open and constructive cooperation between the DESY
XFEL team and the colleagues from European XFEL has been
– and will continue to be – a crucial component for the
achievements at this new world-leading facility.
Much of the success story of the European XFEL accelerator
is based on past developments for and experience with the
FLASH soft X-ray FEL facility at DESY. FLASH itself had
again an excellent year of user operation with high availability
and performance. By now, the parallel operation of the two
undulator beamlines FLASH1 and FLASH2 has become
routine. A refurbishment and improvement programme,
supported by additional investment funding, started in 2017,
and a few items on the to-do list were already completed.
Operation with short bunches (down to single-spike photon
pulses) has been further developed and is now being made
available to users. The sFLASH seeding experiment produced
several new results, including the extraction of detailed and
otherwise hardly accessible properties of the electrons using
time-resolved measurements with the LOLA deflecting structure,
which enables a precise characterisation of the seeded
FEL pulse properties. In the course of the DESY strategy
process, the mid- and longer-term perspectives for improvements
and upgrades at FLASH are being developed and willbe further sharpened, taking into account the scientific priorities
and boundary conditions regarding available resources.
The PETRA III synchrotron radiation source had a very good
operation year, with the highest figure for the availability
(98%) since the facility served its first users in 2010. The
achievement demonstrates that previous improvements in
component and subsystem reliability have paid off. Further
efforts are under way to systematically address the reliability
challenge and stabilise the availability at such an internationally
competitive high level.
Further progress was obtained in the design studies for an
upgrade of PETRA towards an ultralow-emittance storage
ring (PETRA IV). The challenging task of conceiving a layout
with an emittance of <20 pm rad at 6 GeV beam energy and
still sufficient dynamic aperture is being addressed using
different lattice design approaches. A final design decision on
which the further detailed technical layout will be based will
be taken after careful investigation and comparison of the
different options and is foreseen for the end of 2018 or early
2019. Studies of an improved version of the DESY II synchrotron
(DESY IV) have also started, and first preliminary results
indicate that the emittance could be reduced by at least one
order of magnitude with respect to the present machine, an
improvement required for efficient electron injection into the
new PETRA IV ring. In parallel to the lattice design and beam
dynamics studies, first investigations of magnet, girder,
vacuum and RF system concepts were also launched in the
technical groups of the Accelerator Division.
Novel accelerator concepts have become a rapidly growing
field at DESY. The LUX experiment led by the University of
Hamburg demonstrated undulator radiation from an electron
beam with an energy of several hundred MeV produced in alaser-driven plasma wakefield. Moreover, a continuous 24 h
run showed that the accelerated beam had 98% uptime and
was reproducible in energy to a few percent, an important
step towards usable beams from plasma accelerators. Much
progress was obtained with the installation of the electronbeam-
driven plasma wakefield experiment FLASHforward,
and a first electron beam was injected into the FLASHforward
beamline in the FLASH2 tunnel. At the PITZ photoinjector test
facility at DESY in Zeuthen, self-modulation experiments of
the electron bunch in a plasma cell were continued. The
EU-funded multi-GeV laser plasma wakefield acceleration
design study EuPRAXIA, coordinated at DESY, picked up
momentum. Preparations and necessary refurbishments for
the construction of the SINBAD accelerator R& D infrastructure
in the former DORIS building at DESY were completed,
and the first components for the ARES linear accelerator
were ordered. The research perspectives on plasma acceleration
will be strongly boosted by the ATHENA project, for which
the final funding decision within the Helmholtz Association is
expected for the first half of 2018. The SINBAD infrastructure
also integrates the EU-funded AXSIS experiment for THzdriven
acceleration as well as the activities at DESY and the
University of Hamburg within the ACHIP collaboration for
laser-driven microstructure acceleration funded by the
Gordon and Betty Moore Foundation.
The year 2017 was a year of truly outstanding achievements
at DESY as one of the world’s leading accelerator centres,
especially regarding the European XFEL X-ray laser project.
The beam commissioning of the European XFEL accelerator
complex, the demonstration of first hard X-ray free-electron
laser (FEL) radiation and the provision of first photon beams
to users are the most prominent highlights of this remarkably
successful period.
In 2016, the completion of the European XFEL accelerator
construction, the beginning of its technical commissioning
and the successful beam commissioning of the injector had
laid the foundation for the progress that was to follow in
2017. The sections of the superconducting linear accelerator
were successively put into operation, and by April 2017, most
of the radio frequency (RF) sections were active and the
electron beam had reached the beam dump after the accelerator
tunnel. Transport of the beam through the first undulator
line (SASE1) was then quickly established, and after steering
optimisation, a clear FEL radiation signal was observed for
the first time on 2 May. The first lasing was an unplanned, but
most welcome timely match with the concluding meeting of
the DESY-led Accelerator Consortium on 4 May at DESY. At
that event, the 17 institutes involved in the construction of the
accelerator complex reviewed their joint work of the past
seven years and celebrated the completion of their mission.
All involved DESY staff members together with their
colleagues from the collaborating institutes could look with
pride and satisfaction on the achievements in one of the
largest and most challenging projects in the history of DESY.
During the following months, the beam parameters were
further improved, and a photon beam wavelength of 0.13 nm
and a pulse energy of up to about 1 mJ were reached, both
already close to the European XFEL specification. An electron beam energy of 14.9 GeV was achieved with two RF stations
still inactive, which are to be commissioned in 2018. Ramping
up the beam intensity has to be done with care to minimise
radiation damage risk, and in this initial phase, FEL operation
was limited to 30 bunches per accelerator pulse. In machine
studies, however, operation with 300 bunches (3 kHz average
bunch rate) was already successfully demonstrated. The
rapid progress of the beam commissioning was achieved
thanks to reliable and well-performing subsystems, including
diagnostics and controls, and thanks to the strongly committed
and competent operations team. Last but not least, the
very open and constructive cooperation between the DESY
XFEL team and the colleagues from European XFEL has been
– and will continue to be – a crucial component for the
achievements at this new world-leading facility.
Much of the success story of the European XFEL accelerator
is based on past developments for and experience with the
FLASH soft X-ray FEL facility at DESY. FLASH itself had
again an excellent year of user operation with high availability
and performance. By now, the parallel operation of the two
undulator beamlines FLASH1 and FLASH2 has become
routine. A refurbishment and improvement programme,
supported by additional investment funding, started in 2017,
and a few items on the to-do list were already completed.
Operation with short bunches (down to single-spike photon
pulses) has been further developed and is now being made
available to users. The sFLASH seeding experiment produced
several new results, including the extraction of detailed and
otherwise hardly accessible properties of the electrons using
time-resolved measurements with the LOLA deflecting structure,
which enables a precise characterisation of the seeded
FEL pulse properties. In the course of the DESY strategy
process, the mid- and longer-term perspectives for improvements
and upgrades at FLASH are being developed and willbe further sharpened, taking into account the scientific priorities
and boundary conditions regarding available resources.
The PETRA III synchrotron radiation source had a very good
operation year, with the highest figure for the availability
(98%) since the facility served its first users in 2010. The
achievement demonstrates that previous improvements in
component and subsystem reliability have paid off. Further
efforts are under way to systematically address the reliability
challenge and stabilise the availability at such an internationally
competitive high level.
Further progress was obtained in the design studies for an
upgrade of PETRA towards an ultralow-emittance storage
ring (PETRA IV). The challenging task of conceiving a layout
with an emittance of <20 pm rad at 6 GeV beam energy and
still sufficient dynamic aperture is being addressed using
different lattice design approaches. A final design decision on
which the further detailed technical layout will be based will
be taken after careful investigation and comparison of the
different options and is foreseen for the end of 2018 or early
2019. Studies of an improved version of the DESY II synchrotron
(DESY IV) have also started, and first preliminary results
indicate that the emittance could be reduced by at least one
order of magnitude with respect to the present machine, an
improvement required for efficient electron injection into the
new PETRA IV ring. In parallel to the lattice design and beam
dynamics studies, first investigations of magnet, girder,
vacuum and RF system concepts were also launched in the
technical groups of the Accelerator Division.
Novel accelerator concepts have become a rapidly growing
field at DESY. The LUX experiment led by the University of
Hamburg demonstrated undulator radiation from an electron
beam with an energy of several hundred MeV produced in alaser-driven plasma wakefield. Moreover, a continuous 24 h
run showed that the accelerated beam had 98% uptime and
was reproducible in energy to a few percent, an important
step towards usable beams from plasma accelerators. Much
progress was obtained with the installation of the electronbeam-
driven plasma wakefield experiment FLASHforward,
and a first electron beam was injected into the FLASHforward
beamline in the FLASH2 tunnel. At the PITZ photoinjector test
facility at DESY in Zeuthen, self-modulation experiments of
the electron bunch in a plasma cell were continued. The
EU-funded multi-GeV laser plasma wakefield acceleration
design study EuPRAXIA, coordinated at DESY, picked up
momentum. Preparations and necessary refurbishments for
the construction of the SINBAD accelerator R& D infrastructure
in the former DORIS building at DESY were completed,
and the first components for the ARES linear accelerator
were ordered. The research perspectives on plasma acceleration
will be strongly boosted by the ATHENA project, for which
the final funding decision within the Helmholtz Association is
expected for the first half of 2018. The SINBAD infrastructure
also integrates the EU-funded AXSIS experiment for THzdriven
acceleration as well as the activities at DESY and the
University of Hamburg within the ACHIP collaboration for
laser-driven microstructure acceleration funded by the
Gordon and Betty Moore Foundation.