IPAC2011 - List of Authors (Danared, H.)

Paper	Title	Page
MOPC136	The RF Power Source for the High Beta Elliptical Cavities of the ESS Linac	397
	K. Rathsman, H. Danared, R. Zeng ESS, Lund, Sweden A.J. Johansson Lund University, Lund, Sweden C. Lingwood Cockcroft Institute, Lancaster University, Lancaster, United Kingdom R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden C. de Almeida Martins IST-UTL, Lisbon, Portugal
	The European Spallation Source is an intergovernmental project building a multidisciplinary research laboratory based upon the world’s most powerful neutron source. The main facility will be built in Lund, Sweden. Construction is expected to start around 2013 and the first neutrons will be produced in 2019. The ESS linac delivers 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The 120 high beta elliptical cavities, which operate at a frequency of 704 MHz and accelerate protons from 600 MeV to 2.5 GeV, account for more than half of the total number of rf cavities in the ESS linac and three quarter of the total beam power needed. Because of the large number of rf power sources and the high power level needed, all the design and development efforts for the rf power source have so far been focused on this part of the accelerator. The design and development status of the rf power source is reported in this paper with emphasis on reliability, maintainability, safety, power efficiency, investment cost and production capacity.

WEPS059	Layout of the ESS Linac	2631
	H. Danared, M. Eshraqi, W. Hees, A. Jansson, M. Lindroos, S. Peggs, A. Ponton ESS, Lund, Sweden
	The European Spallation Source will use a 2.5 GeV, 50 mA pulsed proton linac to produce an average 5 MW of power on the spallation target. It will consist of normal-conducting part accelerating particles to 50 MeV in an RFQ and a drift-tube linac and a superconducting part with spoke resonators and two families of elliptical cavities. A high-energy beam transport takes the particles through an upgrade section and at least one bend and demagnifies the beam on to the target. The paper will present the current layout of the linac and discuss parameters that define its length from source to target.

WEPS061	ESS LINAC, Design and Beam Dynamics	2637
	M. Eshraqi, H. Danared ESS, Lund, Sweden
	The European Spallation Source, {\sc ESS}, will use a linear accelerator delivering a high intensity proton beam with an average beam power of 5~MW to the target station at 2.5~GeV in long pulses of 2~msec. The ESS {\sc Linac} will use two types of superconducting cavities, spoke resonators at low energy and elliptical cavities at high energies. The possibilities to upgrade to a higher power {\sc Linac} at fixed energy are considered. This paper will present a review of the superconducting {\sc Linac} design and the beam dynamics studies.

WEPS062	Design and Beam Dynamics Study of Hybrid ESS LINAC	2640
	M. Eshraqi, H. Danared, W. Hees, A. Jansson ESS, Lund, Sweden
	The European Spallation Source, {\sc ESS}, will use a superconducting linear accelerator delivering high current long pulses with an average beam power of 5~MW to the target station at 2.5~GeV. A new cryomodule architecture is proposed which allows for a transition between cryomodules in the sub-100~K region, this region can work even at room temperature. This new hybrid design will generate a lower heat load with respect to a fully segmented design - while still providing easy access to individual cryomodules for maintenance and repair. This paper will present a review of the {\sc linac} design, beam dynamics studies and a preliminary cryogenic analysis of the transition region.

WEPS064	Upgrade Strategies for High Power Proton Linacs	2646
	M. Lindroos, H. Danared, M. Eshraqi, D.P. McGinnis, S. Molloy, S. Peggs, K. Rathsman ESS, Lund, Sweden R.D. Duperrier CEA/DSM/IRFU, France J. Galambos ORNL, Oak Ridge, Tennessee, USA
	High power proton linacs are used as drivers for spallation neutron sources, and are proposed as drivers for sub-critical accelerator driven thorium reactors. A linac optimized for a specific average pulse current can be difficult, or inefficient, to operate at higher currents, for example due to mis-matching between the RF coupler and the beam loaded cavity, and due to Higher Order Mode effects. Hardware is in general designed to meet specific engineering values, such as pulse length and repetition rate, that can be costly and difficult to change, for example due to pre-existing space constraints. We review the different upgrade strategies that are available to proton driver designers, both for linacs under design, such as the European Spallation Source (ESS) in Lund, and also for existing linacs, such as the Spallation Neutron Source (SNS) in Oak Ridge. Potential ESS upgrades towards a beam power higher than 5 MW preserve the original time structure, while the SNS upgrade is directed towards the addition of a second target station.

THPS047	New Injection and Extraction at CRYRING for FLAIR	3529
	A. Simonsson, L. Brännholm, S. Das, A. Källberg, P. Löfgren, A. Paal, J. Sjöholm MSL, Stockholm, Sweden H. Danared ESS, Lund, Sweden D. Reistad Intégro Utbildnings AB, Sigtuna, Sweden
	As a preparation for a future transfer of CRYRING to FLAIR at FAIR in Darmstadt, Germany, we have installed and tested a slow extraction system. At FLAIR CRYRING will be used for deceleration of antiprotons from 30 MeV to 0.3 MeV. The tests of the slow extraction show that the beam can be extracted during 2 s with 30-60% efficiency and with rather constant amplitude, apart from noise from 50 Hz harmonics. A new injection system has also been designed. It will be able to inject 30 MeV antiprotons from NESR as well as 0.3 MeV/u ions created in a separate ion source and accelerated in an RFQ.

Paper

Title

Page

The RF Power Source for the High Beta Elliptical Cavities of the ESS Linac

397

K. Rathsman, H. Danared, R. Zeng
ESS, Lund, Sweden
A.J. Johansson
Lund University, Lund, Sweden
C. Lingwood
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
C. de Almeida Martins
IST-UTL, Lisbon, Portugal

The European Spallation Source is an intergovernmental project building a multidisciplinary research laboratory based upon the world’s most powerful neutron source. The main facility will be built in Lund, Sweden. Construction is expected to start around 2013 and the first neutrons will be produced in 2019. The ESS linac delivers 5 MW of power to the target at 2.5 GeV, with a nominal current of 50 mA. The 120 high beta elliptical cavities, which operate at a frequency of 704 MHz and accelerate protons from 600 MeV to 2.5 GeV, account for more than half of the total number of rf cavities in the ESS linac and three quarter of the total beam power needed. Because of the large number of rf power sources and the high power level needed, all the design and development efforts for the rf power source have so far been focused on this part of the accelerator. The design and development status of the rf power source is reported in this paper with emphasis on reliability, maintainability, safety, power efficiency, investment cost and production capacity.

WEPS059

Layout of the ESS Linac

2631

H. Danared, M. Eshraqi, W. Hees, A. Jansson, M. Lindroos, S. Peggs, A. Ponton
ESS, Lund, Sweden

The European Spallation Source will use a 2.5 GeV, 50 mA pulsed proton linac to produce an average 5 MW of power on the spallation target. It will consist of normal-conducting part accelerating particles to 50 MeV in an RFQ and a drift-tube linac and a superconducting part with spoke resonators and two families of elliptical cavities. A high-energy beam transport takes the particles through an upgrade section and at least one bend and demagnifies the beam on to the target. The paper will present the current layout of the linac and discuss parameters that define its length from source to target.

WEPS061

ESS LINAC, Design and Beam Dynamics

2637

M. Eshraqi, H. Danared
ESS, Lund, Sweden

The European Spallation Source, {\sc ESS}, will use a linear accelerator delivering a high intensity proton beam with an average beam power of 5~MW to the target station at 2.5~GeV in long pulses of 2~msec. The ESS {\sc Linac} will use two types of superconducting cavities, spoke resonators at low energy and elliptical cavities at high energies. The possibilities to upgrade to a higher power {\sc Linac} at fixed energy are considered. This paper will present a review of the superconducting {\sc Linac} design and the beam dynamics studies.

WEPS062

Design and Beam Dynamics Study of Hybrid ESS LINAC

2640

M. Eshraqi, H. Danared, W. Hees, A. Jansson
ESS, Lund, Sweden

The European Spallation Source, {\sc ESS}, will use a superconducting linear accelerator delivering high current long pulses with an average beam power of 5~MW to the target station at 2.5~GeV. A new cryomodule architecture is proposed which allows for a transition between cryomodules in the sub-100~K region, this region can work even at room temperature. This new hybrid design will generate a lower heat load with respect to a fully segmented design - while still providing easy access to individual cryomodules for maintenance and repair. This paper will present a review of the {\sc linac} design, beam dynamics studies and a preliminary cryogenic analysis of the transition region.

WEPS064

Upgrade Strategies for High Power Proton Linacs

2646

M. Lindroos, H. Danared, M. Eshraqi, D.P. McGinnis, S. Molloy, S. Peggs, K. Rathsman
ESS, Lund, Sweden
R.D. Duperrier
CEA/DSM/IRFU, France
J. Galambos
ORNL, Oak Ridge, Tennessee, USA

High power proton linacs are used as drivers for spallation neutron sources, and are proposed as drivers for sub-critical accelerator driven thorium reactors. A linac optimized for a specific average pulse current can be difficult, or inefficient, to operate at higher currents, for example due to mis-matching between the RF coupler and the beam loaded cavity, and due to Higher Order Mode effects. Hardware is in general designed to meet specific engineering values, such as pulse length and repetition rate, that can be costly and difficult to change, for example due to pre-existing space constraints. We review the different upgrade strategies that are available to proton driver designers, both for linacs under design, such as the European Spallation Source (ESS) in Lund, and also for existing linacs, such as the Spallation Neutron Source (SNS) in Oak Ridge. Potential ESS upgrades towards a beam power higher than 5 MW preserve the original time structure, while the SNS upgrade is directed towards the addition of a second target station.

THPS047

New Injection and Extraction at CRYRING for FLAIR

3529

A. Simonsson, L. Brännholm, S. Das, A. Källberg, P. Löfgren, A. Paal, J. Sjöholm
MSL, Stockholm, Sweden
H. Danared
ESS, Lund, Sweden
D. Reistad
Intégro Utbildnings AB, Sigtuna, Sweden

As a preparation for a future transfer of CRYRING to FLAIR at FAIR in Darmstadt, Germany, we have installed and tested a slow extraction system. At FLAIR CRYRING will be used for deceleration of antiprotons from 30 MeV to 0.3 MeV. The tests of the slow extraction show that the beam can be extracted during 2 s with 30-60% efficiency and with rather constant amplitude, apart from noise from 50 Hz harmonics. A new injection system has also been designed. It will be able to inject 30 MeV antiprotons from NESR as well as 0.3 MeV/u ions created in a separate ion source and accelerated in an RFQ.