| 1. |
- Bengtsson, Lars, 1963
(författare)
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Generation and measurement of pulses and delays with RISC-controllers
- 1997
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Ingår i: Measurement Science and Technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 8, s. 679-683
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Tidskriftsartikel (refereegranskat)abstract
- An instrument for the generation of pulses and delays has beendeveloped for applications in laserspectroscopy experiments. The pulses from achopped laserbeam are counted, and when a preset value is reached, two signalsare generated: one delayed trigger pulse with constant length and one delayed‘shutter pulse’ (referred to as the ‘shutter window’ below) which opens a light shutterand allows one light pulse to enter the experimental region and excite the sample.The delays of the trigger pulse and the shutter window and the width of the shutterwindow can all be set independently to any value from 0 up to 50 ms with 0.05 mssteps. A separate microcontroller measures the width of the shutter window with anaccuracy of 1micro seconds. The pulse delays and the width of the shutter window are setwith thumbwheel potentiometers connected as voltage dividers. A microcontrollerreads the set values with a four-channel, 12-bit AD converter. This techniquesaves a lot of hardware wiring as well as software writing when compared to thealternative of using separate, BCD-coded thumbwheels for each timesetting.In total, the instrument consists of two independent RISC-controllers: onePIC16C55 for counting chopper pulses and generating pulses and delays, and onePIC16C74 for measuring (and displaying) the width of the shutter window. Thewidth of the shutter window is measured with 1micro second resolution by taking fulladvantage of two different peripherial I/O devices in the PIC16C74: the 16-bit ‘inputcapture’ module and the external interrupt facility.
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| 2. |
- Sorensen, S.L., et al.
(författare)
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A normal-incidence beam line at the MAX storage ring
- 1990
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0168-9002. ; 297:1-2, s. 296-300
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Tidskriftsartikel (refereegranskat)abstract
- A 1-m normal-incidence monochromator has been designed and installed on a bending-magnet beam line at the MAX storage ring in Lund. The optical properties of the beam line have been investigated via ray-tracing studies and with flux measurements of the beam line-monochromator combination. A resolution of 0.9 Å at 919.8 Å was measured in first-order diffraction with an argon hollow-cathode lamp for slit openings of 100 μm. A photon flux of 2.0 × 1010 at 550 Å with 250 μm slits was measured with a calibrated GaAs photodiode through a 1.5-mm diameter aperture in an aluminum mask on the photodiode. The new instrument has a microcomputer controlled mechanism which optimizes focussing requirements for a scanning monochromator with the requirement of fixed slits and fixed exit beam.
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| 3. |
- Bengtsson, Lars, 1963
(författare)
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Avancerad Elektrisk Mätteknik
- 1996
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Boken är avsedd för fortsättnigskurser i elektrisk mätteknik på högskolenivå. Den lämpar sig också väl som kompletteringslitteratur för kurser i signalbehandling. Innehållet är framför allt koncentrerat till analog och digital frekvensanalys, brusreducerande mätmetoder och AD/DA-omvandlingsmetoder. Ett kapitel tar upp signalbehandling och sambanden mellan analys i tid och rum. Fouriertransformen och faltningsintegralen gås igenom i detalj. Boken avslutas dels med ett kapitel om snabba förlopp i transmissionsledningar, dels med ett kapitel om GPIB-bussen. I appendix finns även en beskrivning av RS-232-kommunikation.
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| 4. |
- Adler, Jan-Olof, et al.
(författare)
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A broad range tagging spectrometer for the MAX-laboratory
- 1997
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 388:1-2, s. 17-26
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Tidskriftsartikel (refereegranskat)abstract
- A broad range tagging spectrometer together with a new beam transport system for photonuclear experiments at the MAX-laboratory in Lund is described. The spectrometer consists of a quadrupole followed by an Elbek-type dipole and has a large momentum acceptance. It can produce both polarized and unpolarized tagged photons in the energy range 10–80 MeV with an energy resolution of about 300 keV.
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| 5. |
- Almehed, Sverker, et al.
(författare)
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A Silicon-Tungsten Electromagnetic Calorimeter for LEP
- 1991
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 305:2, s. 320-330
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Tidskriftsartikel (refereegranskat)abstract
- This report describes a silicon-tungsten electromagnetic calorimeter used to determine some beam properties and luminosity in the DELPHI experiment at LEP. The polar angular range covered by this detector is 5–8 mrad, which allows the detection of a Bhabha rate about 10 times the rate of produced Z particles at the peak cross section.
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| 6. |
- Anderson, D., et al.
(författare)
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A variational approach to spherical aberrations in the thermal-wave model for beam dynamics in charged particle accelerators
- 1998
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Ingår i: Physica Scripta. - : Institute of Physics Publishing. - 0031-8949 .- 1402-4896. ; 58:6, s. 608-612
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Tidskriftsartikel (refereegranskat)abstract
- A direct variational approach involving trial functions and Ritz optimization, which has previously been found very useful in nonlinear optics, is applied to analyze the effects of spherical aberrations on the focusing properties of charged particle beams in particle colliders. As compared to conventional perturbation theory, the variational approach provides a simple and physically clear analysis. Explicit expressions are given for the transverse particle beam density, the spot size, and the luminosity reduction factor at the interaction point, in good agreement with the perturbative results.
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| 7. |
- Andersson, Åke, et al.
(författare)
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Beam profile measurements at MAX
- 1995
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 364:1, s. 4-12
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Tidskriftsartikel (refereegranskat)abstract
- An electron beam profile monitor system is described. It utilizes the visible bending magnet synchrotron radiation (SR) to form an image of the beam. A model for calculating diffraction and depth of field effects is introduced. Assuming a Gaussian distributed electron beam, the relation between beam image size and actual beam size is then calculated with this model, for a number of practical measuring situations. In a series of measurements at the MAX I electron storage ring at a current of 1 mA, the beam image size has been measured for these calculated situations. The measured values are presented, and their behaviour is in good agreement with the model. With this model the horizontal and vertical rms beam sizes were determined to σx = (203 ± 3) μm and σy = (19 ± 3) μm respectively. The corresponding vertical emittance is approximately 0.05 nm rad.
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| 8. |
- Andersson, Åke, et al.
(författare)
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Emittance manipulation by first- and second-order lattice control
- 1997
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0168-9002. ; 387:3, s. 463-470
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Tidskriftsartikel (refereegranskat)abstract
- The lattice of the MAX-I electron storage ring has been investigated and tuned towards small momentum compaction values. By measurements of the synchrotron frequency, bunch length, horizontal beam size and beam movement, the beam has been found to behave in reasonable agreement with the predictions of the lattice model up to second order in energy deviation. Both longitudinal and horizontal emittance could be varied within a relatively large range with lattice changes and/or controlled beam energy changes.
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| 9. |
- Andersson, Åke, et al.
(författare)
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Experiences with the narrow gap undulator at MAX-lab
- 1995
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 362:2-3, s. 586-591
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Tidskriftsartikel (refereegranskat)abstract
- An undulator with short poles (period 24 mm) and extremely narrow gap (magnet gap 7.7 mm) using a squeezable vacuum chamber has been installed and is in operation at the MAX-lab 550 MeV storage ring. The device operates with a vacuum chamber aperture down to 6.2 mm. The behaviour of the storage ring concerning lifetime, emittance, tune shift and closed orbit is well described by conventional models. We present here the design of the device, the influence on the storage ring and the spectral characteristics, as well as comparison with expected theoretical results and an overview of the activities at the beam line.
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| 10. |
- Andersson, Åke, et al.
(författare)
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Landau cavities at MAX II
- 1998
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 416:2-3, s. 465-474
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Tidskriftsartikel (refereegranskat)abstract
- Passive Landau cavities have been built, installed and taken into regular operation in the MAX II ring. The purpose of the Landau damping system is twofold: to decrease the energy spread of the beam induced by coupled bunch oscillations and to increase the Touschek life-time. The cavities are of the pillbox type operated at 1500 MHz, the third harmonic of the main RF. This paper describes the design, tuning and operational results of the cavities.
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