Åke Andersson | Stikes Muhammadiyah Lhokseumawe (original) (raw)
Papers by Åke Andersson
In the scope of the LEG Project [1] it has been decided to build a 100 keV gun test stand. In thi... more In the scope of the LEG Project [1] it has been decided to build a 100 keV gun test stand. In this test stand, we attempt to compensate emittance blow-up due to space charge forces with a solenoid magnet. The solenoid magnet has recently been manufactured to our specifications at PSI. In the test stand, the solenoid is sealed off from the vacuum surroundings by a UHV-compatible welded steel casing. We wanted to measure the solenoid properties and verify that it fulfills design specifications, before it was definitely welded into the steel casing. The measurement procedures and results are presented in this paper.
1996 IEEE International Conference on Acoustics, Speech, and Signal Processing Conference Proceedings
In the present paper a second order recursive algorithm for subspace tracking is proposed. The tr... more In the present paper a second order recursive algorithm for subspace tracking is proposed. The tracking capabilities of the proposed algorithm is demonstrated via some simulation examples and the algorithm is compared with the corresponding first order algorithm. The proposed algorithm has good tracking capabilities, such as smooth behavior of the trajectories and fast adaptation. The proposed algorithm has the same computational complexity as has the first order algorithm, but some extra memory storage is required.
The MAX IV 3 GeV storage ring based on a multibend achromat lattice allows for horizontal emittan... more The MAX IV 3 GeV storage ring based on a multibend achromat lattice allows for horizontal emittances from 330 pm rad down to 180 pm rad, depending on the number of insertion devices. The diagnostics used during commissioning will be described, with emphasis on the emittance diagnostics. This will involve two diagnostic beam lines to image the electron beam with infrared and ultraviolet synchrotron radiation from bending magnets, in order to determine also beam energy spread. The scheme for horizontal emittance measurements looks promising also for an order of magnitude lower emittance. Bunch lengthening with harmonic cavities is essential for the low emittance machine performance. We have used a radiation-based sampling technique to verify individual bunch distributions. (Less)
The emittances of the electron beams at the MAX-laboratory accelerator system have been studied. ... more The emittances of the electron beams at the MAX-laboratory accelerator system have been studied. Apart from the build-up of the diagnostic tools for precise determination of the beam spatial profiles, the objectives have been: a) to verify the accelerator design emittances at low currents and to try to determine the emittances also at high currents; b) to investigate possibilities to manipulate the emittances. The method for emittance determination was optical measurements of the electron beam profiles. Then, by different means the accelerator lattice functions were estimated at the observation point. From this knowledge and from measurements of the synchrotron frequency, the emittances in all three dimensions were determined. As a consequence of the desire to determine very low transverse emittances, a theoretical model for the emission and focusing of synchrotron radiation had to be employed. A model based on classical electrodynamics and wave-optics was chosen. The accuracy of th...
The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required... more The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required a beam size monitor with the ability to verify a sub-pm·rad vertical emittance. This corresponds to a beam height of less than 4 µm. Within the TIARA Work Package ’SLS Vertical Emittance Tuning’ a new beam size monitor was designed and built. The monitor is based on the imaging of the �-polarized synchrotron radiation (SR) in the visible and UV spectral ranges. Besides imaging, the monitor provides interferometric methods using vertically or horizontally polarized SR. With these complementary methods the consistency of beam size measurements is verified. An intermediate configuration of the monitor beamline using a lens as the focusing element has been commissioned in 2013. With this setup a vertical beam size of 4.8± 0.5 µm, corresponding to a vertical emittance of 1.7± 0.4 pm·rad has been measured. During 2014 the monitor was commissioned in its final configuration with a toroidal mir...
At synchrotron light storage rings there is demand for serving both high-brilliance and timing us... more At synchrotron light storage rings there is demand for serving both high-brilliance and timing users simultaneously. At many rings this is commonly achieved by operating fill patterns with gaps of sufficient length, but this is not favorable for rings that operate with passive harmonic cavities to damp instabilities and increase Touschek lifetime by lengthening the bunches. For such rings, gaps in the fill pattern could severely reduce the achievable bunch lengths. For the MAX IV 3 GeV storage ring, sufficient bunch lengthening is also essential for conserving the ultralow emittance and reducing heat load on vacuum components at high current. It is therefore of interest to study methods to serve timing users while operating without gap in the fill pattern. Once such method is PPRE, where the transverse emittance of one bunch in the bunch train is increased by an incoherent betatron excitation. This paper presents simulations for the MAX IV 3 GeV storage ring and discusses the machin...
MAX-I11 is a 700 MeV storage ring for synchrotron radiation that is being built at MAX-lab. The r... more MAX-I11 is a 700 MeV storage ring for synchrotron radiation that is being built at MAX-lab. The ring will provide radiation in the UV and IR spectral regions. The ring will have a 100 MHz RF system combined with a 500 MHz passive Landau cavity. The lattice is compact, with combined fknction magnets. The magnets are integrated into the girder providing for ease of alignment.
An extremely small vertical beam size of 3.6 μm, corre- sponding to a vertical emittance of 0.9 p... more An extremely small vertical beam size of 3.6 μm, corre- sponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The mea- surement was performed by means of a beam size moni- tor based on the imaging of the vertically polarized syn- chrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented fur- ther emittance minimization. In the context of the work package SLS Vertical Emittance Tuning of the TIARA col- laboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.
Journal of Electron Spectroscopy and Related Phenomena, 2018
The commissioning of the MAX IV synchrotron radiation facility in Lund marks the dawn of a new ge... more The commissioning of the MAX IV synchrotron radiation facility in Lund marks the dawn of a new generation of storagering-based light sources. This new generation delivers orders-of-magnitude higher performance and allows realization of groundbreaking experiments on a variety of systems and materials at the atomic and molecular levels. This talk reviews the conceptual basis of the MAX IV design, summarizes the most recent accelerator commissioning results and explores future development paths for the MAX IV light sources aimed at achieving the diffraction limit at hard X-ray wavelengths.
Journal of synchrotron radiation, 2018
The MAX IV 3 GeV electron storage ring in Lund, Sweden, is the first of a new generation of light... more The MAX IV 3 GeV electron storage ring in Lund, Sweden, is the first of a new generation of light sources to make use of the multibend-achromat lattice (MBA) to achieve ultralow emitance and hence ultrahigh brightness and transverse coherence. The conceptual basis of the MAX IV 3 GeV ring project combines a robust lattice design with a number of innovative engineering choices: compact, multifunctional magnet blocks, narrow low-conductance NEG-coated copper vacuum chambers and a 100 MHz radio-frequency system with passively operated third-harmonic cavities for bunch lengthening. In this paper, commissioning and first-year operational results of the MAX IV 3 GeV ring are presented, highlighting those aspects that are believed to be most relevant for future MBA-based storage rings. The commissioning experience of the MAX IV 3 GeV ring offers in this way an opportunity for validation of concepts that are likely to be essential ingredients of future diffraction-limited light sources.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2018
The MAX IV 3 GeV storage ring is the first light source to make use of a multibend achromat latti... more The MAX IV 3 GeV storage ring is the first light source to make use of a multibend achromat lattice to reach ultralow emittance. After extensive commissioning efforts, the storage ring is now ramping up its user program. We present results from beam commissioning of the MAX IV 3 GeV storage ring as well as a summary of the beam dynamics studies that have so for been carried out. We report on injection and accumulation using a single dipole kicker, top-up injection, slow orbit feedback, restoring the linear optics to design, effects of in-vacuum undulators with closed gaps, adjusting nonlinear optics to achieve design chromaticity correction and dynamic aperture sufficient for high injection efficiency and large Touschek lifetime.
This study investigates the digital presence of cultural centers in three regions of Germany taki... more This study investigates the digital presence of cultural centers in three regions of Germany taking into account the theoretical framework of the knowledge age. In order to find out if the adaption of online tools has a positive influence on visitor reach, i.e. on the success of the centers, the thesis attempts to gather information on online tool usage of individual institutions via questionnaires. Taking into consideration the overall context three factors referring to traditional economic concepts namely industry size, institution size and program diversity are proposed as additional success factors. The research results indicate that digital presence, together with the other measured factors, have a positive impact on the success of the centers. Moreover, the cultural infrastructure appears to have a direct positive impact on industry size and, consequently, an indirect impact on the success of cultural centers.
Ion Implantation in Semiconductors, 1971
Silicon crystals with implanted layers of phosphorus and arsenic have been well annealed and subs... more Silicon crystals with implanted layers of phosphorus and arsenic have been well annealed and subsequently bombarded with small additional doses of phosphorus or arsenic ions and the changes in the electrical behaviour studied. For both types of implanted ions there was a decrease in the number of carriers as a result of the additional bombardment. This decrease was associated with an increase in the carrier mobility for those specimens which had originally been implanted with a high dose of phosphorus ions, but with a decrease in the mobility for those which had been implanted with arsenic ions. Some of the specimens were isochronally annealed after the additional implantation.
Dynamics and Conflict in Regional Structural Change, 1990
ABSTRACT
An RF-gun structure developed at MAX-lab, and thus different from the most common BNL-structure, ... more An RF-gun structure developed at MAX-lab, and thus different from the most common BNL-structure, is in operation as a thermionic RF-gun at MAX-lab. The properties of the gun have been investigated. Especially aspects such as extractable energy range, emittance properties at various beam loading conditions and extracted current.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2000
A new pre-injector for the MXX-Laboratory is under design and constructwn. A therrnionic rf gun, ... more A new pre-injector for the MXX-Laboratory is under design and constructwn. A therrnionic rf gun, designed to operate at medium currents with hw back bombardment power, is under construction. The gun will, via a magnetic compressor and energy jilter, feed a recirculated linac consisting of two SLED-equipped structures giving 125 MeV each. The jirst will be delivered in 1999. The system is aimed as a pre-injector for the m"sting storage rings at &MX-Lab, but will aLro open up possibilities for a SASE FEL in the W reaching above 100 MW below 100 run.
Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366), 1999
In December 1998 the FRN-The Swedish Council for Planning and Coordination of Research-decided to... more In December 1998 the FRN-The Swedish Council for Planning and Coordination of Research-decided to fund a new injector and storage ring for the MAX-laboratory. The system will consist of a 50-MeV linac, a 600-MeV booster synchrotron, and a 600-MeV storage ring for VUV undulator beamlines. The system will replace an old 100-MeV racetrack microtron and will inject the two existing storage rings: the 550-MeV MAX I and the 1.5-GeV MAX II, as well as the new 600-MeV storage ring. The linac injector will also be designed with intentions to provide electrons for a future infrared free-electron laser (IR-FEL) facility. The detailed design of the system began in January 1999 with a planned first beam in the summer of 2001.
The American Journal of Surgery, 1977
Papers in Regional Science, 2005
In the scope of the LEG Project [1] it has been decided to build a 100 keV gun test stand. In thi... more In the scope of the LEG Project [1] it has been decided to build a 100 keV gun test stand. In this test stand, we attempt to compensate emittance blow-up due to space charge forces with a solenoid magnet. The solenoid magnet has recently been manufactured to our specifications at PSI. In the test stand, the solenoid is sealed off from the vacuum surroundings by a UHV-compatible welded steel casing. We wanted to measure the solenoid properties and verify that it fulfills design specifications, before it was definitely welded into the steel casing. The measurement procedures and results are presented in this paper.
1996 IEEE International Conference on Acoustics, Speech, and Signal Processing Conference Proceedings
In the present paper a second order recursive algorithm for subspace tracking is proposed. The tr... more In the present paper a second order recursive algorithm for subspace tracking is proposed. The tracking capabilities of the proposed algorithm is demonstrated via some simulation examples and the algorithm is compared with the corresponding first order algorithm. The proposed algorithm has good tracking capabilities, such as smooth behavior of the trajectories and fast adaptation. The proposed algorithm has the same computational complexity as has the first order algorithm, but some extra memory storage is required.
The MAX IV 3 GeV storage ring based on a multibend achromat lattice allows for horizontal emittan... more The MAX IV 3 GeV storage ring based on a multibend achromat lattice allows for horizontal emittances from 330 pm rad down to 180 pm rad, depending on the number of insertion devices. The diagnostics used during commissioning will be described, with emphasis on the emittance diagnostics. This will involve two diagnostic beam lines to image the electron beam with infrared and ultraviolet synchrotron radiation from bending magnets, in order to determine also beam energy spread. The scheme for horizontal emittance measurements looks promising also for an order of magnitude lower emittance. Bunch lengthening with harmonic cavities is essential for the low emittance machine performance. We have used a radiation-based sampling technique to verify individual bunch distributions. (Less)
The emittances of the electron beams at the MAX-laboratory accelerator system have been studied. ... more The emittances of the electron beams at the MAX-laboratory accelerator system have been studied. Apart from the build-up of the diagnostic tools for precise determination of the beam spatial profiles, the objectives have been: a) to verify the accelerator design emittances at low currents and to try to determine the emittances also at high currents; b) to investigate possibilities to manipulate the emittances. The method for emittance determination was optical measurements of the electron beam profiles. Then, by different means the accelerator lattice functions were estimated at the observation point. From this knowledge and from measurements of the synchrotron frequency, the emittances in all three dimensions were determined. As a consequence of the desire to determine very low transverse emittances, a theoretical model for the emission and focusing of synchrotron radiation had to be employed. A model based on classical electrodynamics and wave-optics was chosen. The accuracy of th...
The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required... more The Swiss Light Source (SLS) campaign on vertical emittance minimization and measurement required a beam size monitor with the ability to verify a sub-pm·rad vertical emittance. This corresponds to a beam height of less than 4 µm. Within the TIARA Work Package ’SLS Vertical Emittance Tuning’ a new beam size monitor was designed and built. The monitor is based on the imaging of the �-polarized synchrotron radiation (SR) in the visible and UV spectral ranges. Besides imaging, the monitor provides interferometric methods using vertically or horizontally polarized SR. With these complementary methods the consistency of beam size measurements is verified. An intermediate configuration of the monitor beamline using a lens as the focusing element has been commissioned in 2013. With this setup a vertical beam size of 4.8± 0.5 µm, corresponding to a vertical emittance of 1.7± 0.4 pm·rad has been measured. During 2014 the monitor was commissioned in its final configuration with a toroidal mir...
At synchrotron light storage rings there is demand for serving both high-brilliance and timing us... more At synchrotron light storage rings there is demand for serving both high-brilliance and timing users simultaneously. At many rings this is commonly achieved by operating fill patterns with gaps of sufficient length, but this is not favorable for rings that operate with passive harmonic cavities to damp instabilities and increase Touschek lifetime by lengthening the bunches. For such rings, gaps in the fill pattern could severely reduce the achievable bunch lengths. For the MAX IV 3 GeV storage ring, sufficient bunch lengthening is also essential for conserving the ultralow emittance and reducing heat load on vacuum components at high current. It is therefore of interest to study methods to serve timing users while operating without gap in the fill pattern. Once such method is PPRE, where the transverse emittance of one bunch in the bunch train is increased by an incoherent betatron excitation. This paper presents simulations for the MAX IV 3 GeV storage ring and discusses the machin...
MAX-I11 is a 700 MeV storage ring for synchrotron radiation that is being built at MAX-lab. The r... more MAX-I11 is a 700 MeV storage ring for synchrotron radiation that is being built at MAX-lab. The ring will provide radiation in the UV and IR spectral regions. The ring will have a 100 MHz RF system combined with a 500 MHz passive Landau cavity. The lattice is compact, with combined fknction magnets. The magnets are integrated into the girder providing for ease of alignment.
An extremely small vertical beam size of 3.6 μm, corre- sponding to a vertical emittance of 0.9 p... more An extremely small vertical beam size of 3.6 μm, corre- sponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The mea- surement was performed by means of a beam size moni- tor based on the imaging of the vertically polarized syn- chrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented fur- ther emittance minimization. In the context of the work package SLS Vertical Emittance Tuning of the TIARA col- laboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.
Journal of Electron Spectroscopy and Related Phenomena, 2018
The commissioning of the MAX IV synchrotron radiation facility in Lund marks the dawn of a new ge... more The commissioning of the MAX IV synchrotron radiation facility in Lund marks the dawn of a new generation of storagering-based light sources. This new generation delivers orders-of-magnitude higher performance and allows realization of groundbreaking experiments on a variety of systems and materials at the atomic and molecular levels. This talk reviews the conceptual basis of the MAX IV design, summarizes the most recent accelerator commissioning results and explores future development paths for the MAX IV light sources aimed at achieving the diffraction limit at hard X-ray wavelengths.
Journal of synchrotron radiation, 2018
The MAX IV 3 GeV electron storage ring in Lund, Sweden, is the first of a new generation of light... more The MAX IV 3 GeV electron storage ring in Lund, Sweden, is the first of a new generation of light sources to make use of the multibend-achromat lattice (MBA) to achieve ultralow emitance and hence ultrahigh brightness and transverse coherence. The conceptual basis of the MAX IV 3 GeV ring project combines a robust lattice design with a number of innovative engineering choices: compact, multifunctional magnet blocks, narrow low-conductance NEG-coated copper vacuum chambers and a 100 MHz radio-frequency system with passively operated third-harmonic cavities for bunch lengthening. In this paper, commissioning and first-year operational results of the MAX IV 3 GeV ring are presented, highlighting those aspects that are believed to be most relevant for future MBA-based storage rings. The commissioning experience of the MAX IV 3 GeV ring offers in this way an opportunity for validation of concepts that are likely to be essential ingredients of future diffraction-limited light sources.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2018
The MAX IV 3 GeV storage ring is the first light source to make use of a multibend achromat latti... more The MAX IV 3 GeV storage ring is the first light source to make use of a multibend achromat lattice to reach ultralow emittance. After extensive commissioning efforts, the storage ring is now ramping up its user program. We present results from beam commissioning of the MAX IV 3 GeV storage ring as well as a summary of the beam dynamics studies that have so for been carried out. We report on injection and accumulation using a single dipole kicker, top-up injection, slow orbit feedback, restoring the linear optics to design, effects of in-vacuum undulators with closed gaps, adjusting nonlinear optics to achieve design chromaticity correction and dynamic aperture sufficient for high injection efficiency and large Touschek lifetime.
This study investigates the digital presence of cultural centers in three regions of Germany taki... more This study investigates the digital presence of cultural centers in three regions of Germany taking into account the theoretical framework of the knowledge age. In order to find out if the adaption of online tools has a positive influence on visitor reach, i.e. on the success of the centers, the thesis attempts to gather information on online tool usage of individual institutions via questionnaires. Taking into consideration the overall context three factors referring to traditional economic concepts namely industry size, institution size and program diversity are proposed as additional success factors. The research results indicate that digital presence, together with the other measured factors, have a positive impact on the success of the centers. Moreover, the cultural infrastructure appears to have a direct positive impact on industry size and, consequently, an indirect impact on the success of cultural centers.
Ion Implantation in Semiconductors, 1971
Silicon crystals with implanted layers of phosphorus and arsenic have been well annealed and subs... more Silicon crystals with implanted layers of phosphorus and arsenic have been well annealed and subsequently bombarded with small additional doses of phosphorus or arsenic ions and the changes in the electrical behaviour studied. For both types of implanted ions there was a decrease in the number of carriers as a result of the additional bombardment. This decrease was associated with an increase in the carrier mobility for those specimens which had originally been implanted with a high dose of phosphorus ions, but with a decrease in the mobility for those which had been implanted with arsenic ions. Some of the specimens were isochronally annealed after the additional implantation.
Dynamics and Conflict in Regional Structural Change, 1990
ABSTRACT
An RF-gun structure developed at MAX-lab, and thus different from the most common BNL-structure, ... more An RF-gun structure developed at MAX-lab, and thus different from the most common BNL-structure, is in operation as a thermionic RF-gun at MAX-lab. The properties of the gun have been investigated. Especially aspects such as extractable energy range, emittance properties at various beam loading conditions and extracted current.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2000
A new pre-injector for the MXX-Laboratory is under design and constructwn. A therrnionic rf gun, ... more A new pre-injector for the MXX-Laboratory is under design and constructwn. A therrnionic rf gun, designed to operate at medium currents with hw back bombardment power, is under construction. The gun will, via a magnetic compressor and energy jilter, feed a recirculated linac consisting of two SLED-equipped structures giving 125 MeV each. The jirst will be delivered in 1999. The system is aimed as a pre-injector for the m"sting storage rings at &MX-Lab, but will aLro open up possibilities for a SASE FEL in the W reaching above 100 MW below 100 run.
Proceedings of the 1999 Particle Accelerator Conference (Cat. No.99CH36366), 1999
In December 1998 the FRN-The Swedish Council for Planning and Coordination of Research-decided to... more In December 1998 the FRN-The Swedish Council for Planning and Coordination of Research-decided to fund a new injector and storage ring for the MAX-laboratory. The system will consist of a 50-MeV linac, a 600-MeV booster synchrotron, and a 600-MeV storage ring for VUV undulator beamlines. The system will replace an old 100-MeV racetrack microtron and will inject the two existing storage rings: the 550-MeV MAX I and the 1.5-GeV MAX II, as well as the new 600-MeV storage ring. The linac injector will also be designed with intentions to provide electrons for a future infrared free-electron laser (IR-FEL) facility. The detailed design of the system began in January 1999 with a planned first beam in the summer of 2001.
The American Journal of Surgery, 1977
Papers in Regional Science, 2005