• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 10
  • 1
  • 1
  • 1
  • Tagged with
  • 13
  • 5
  • 5
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

LAUE MONOCHROMATOR PERFORMANCE CALCULATIONS FOR A FUTURE CANADIAN LIGHT SOURCE DIFFRACTION BEAMLINE

Dina, Gabriel 31 October 2011 (has links)
The computational investigation of perfect and bent crystals both cylindrically and sagittaly, have led to the development of sets of optimized parameters to be used for the high energy wiggler beamline monochromator being built at the CLS. Using both Si and Ge in Bragg and Laue geometries, the developed algorithms examine parameter space for most photon flux at the crystal. Using programs in XOP, the calculation analysis for a single incident beam revealed that for symmetric flat crystals the reflection (1,1,1) in the Bragg geometry is most preferable for producing the most throughput at energies below 24keV. For cylindrically bent crystals at energies higher than 24keV, a Laue geometry is more preferred as a result of an increase in the rocking curve width and throughput. Development of a program that calculates the diffracted intensity and energy resolution of a saddle bent crystal with varying asymmetry angles are presented here.
2

A Mini-PET beamline for optimized proton delivery to the ISOTRACE™ target system

Dehnel, M. P., Jackle, P., Potkins, D., Stewart, T., Boudreault, G., Jones, T., Philpott, C. 19 May 2015 (has links) (PDF)
Introduction The ISOTRACE™ Super-Conducting Cyclotron is PMB-Alcen’s redeveloped and modernized version of Oxford Instrument’s OSCAR superconducting cyclotron [1]. Its extracted 80+ mi-croamperes of 12 MeV protons are used for the production of PET radioisotopes. Following the philosophy of Dickie, Stevenson, Szlavik [2] for minimizing dose to personnel, and as developed by Dehnel et al [3,4], and Stokely et al [5], the ISOTRACE™ shall utilize an innovative, light-weight, integrated and self-supporting Mini-Beamline. This permits the relatively high residual radiation fields around PET targets to be moved ~1 metre away from the cyclotron, and facilitates the use of local shielding (around the targets) that limits prompt gammas and neutrons, but more importantly attenuates the residual target radiation, so that maintenance/research staff can work on the cyclotron in a relatively low activity environment. In addition, the mini-beamline for PET utilizes a compound quadrupole/steerer doublet that permits active and dynamic focusing/steering of the extracted proton beam for optimized production and minimized losses [3], so it improves on the successful work of Theroux et al [6]. The integrated beamline unit is extremely small, so that it is very unlike bulky traditional PET and SPECT beamlines that require substantial support structures, such as described by Dehnel in [7,8]. Material and Methods The ISOTRACE™ cyclotron is pictured in FIG. 1. The exit port flange and gate valve to which the integrated mini-beamline for PET shall be mounted is shown. Immediately upstream of the exit port, hidden from view, is a 4 jaw collimator (called BPI for Beam Position Indicator) with spilled beam current readbacks to the control system. TABLE 1 shows the nominal beam emittance and Twiss parameter values at the exit port flange location. This ion-optical information is necessary to simulate ion beam transport, develop the mini-beamline, and determine a nominal tune (i.e. magnet settings). Results and Conclusion TABLE 2 shows the ion-optical system parameters. FIGS. 2 and 3 show the horizontal and vertical beam profiles. The Horizontally focusing Quadrupole magnet (HQ), and Vertically focusing Quadrupole magnet (VQ) aperture diameter, 33 mm, was chosen to give sufficient beam acceptance. The focusing strength is a function of BL, so the effective length, L = 150 mm, was chosen to ensure Bmax less than 0.3 Tesla, while keeping overall magnet mass down. The quad-rupole magnets are fitted with water-cooled compound coils in which the copper/mylar strip wound portion of each coil is a winding for the quadrupole focusing function, and the wire wound portion is for the steering function. To increase beam acceptance and provide additional section strength for the pipe support function, the internal aperture of the low-activation aluminium beam pipe and the external shape are in the shape of a cross. FIG. 4 shows the beam crosssection at the mid-point of the downstream quadrupole magnet, and illustrates the additional acceptance as compared to a round beampipe. In order to machine the interior profile, the pipe is comprised of two premachined pieces that are friction stirwelded together. FIG. 5 is an isometric of the mini-beamline for PET. The four upstream HQ compound coils are excited with a 75A power supply for the horizontally focusing quadrupole magnet function, and a ± 10A power supply for a vertical steering function. The same power supplies are used for the four downstream VQ compound coils for the purpose of a vertically focusing quadrupole magnet function and horizontal steering function.
3

Annual Report 2009/10 Rossendorf Beamline at ESRF (ROBL-CRG)

19 July 2012 (has links) (PDF)
The Rossendorf Beamline (ROBL) - located at BM20 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France - is in operation since 1998. This 7th report covers the period from January 2009 to December 2010. In these two years, 67 peer- reviewed papers have been published based on experiments done at the beamline, more than in any biannual period before. Six highlight reports have been selected for this report to demonstrate the scientific strength and diversity of the experiments performed on the two end-stations of the beamline, dedicated to Radiochemistry (RCH) and Materials Research (MRH). The beamtime was more heavily overbooked than ever before, with an acceptance rate of only 25% experiments. We would like to thank our external proposal review members, Prof. Andre Maes (KU Leuven, Belgium), Prof. Laurent Charlet (UJF Grenoble, France), Dr. Andreas Leinweber (MPI Metallforschung, Stuttgart, Germany), Prof. David Rafaja (TU Bergakademie Freiberg, Germany), Prof. Dirk Meyer (TU Dresden, Germany), who evaluated the inhouse proposals in a thorough manner, thereby ensuring that beamtime was distributed according to scientific merit. The period was not only characterized by very successful science, but also by intense work on the optics upgrade. In spring 2009, a workshop was held at ROBL, assembling beamline experts from German, Spanish and Swiss synchrotrons, to evaluate the best setup for the new optics. These suggestions was used to prepare the call for tender published in July 2009. From the tender acceptance in November 2009 on, a series of design review meetings and factory acceptance tests followed. Already in July 2010, the first piece of equipment was delivered, the new double-crystal, double-multilayer monochromator. The disassembly of the old optics components started end of July, 2011, followed by the installation of the new components. As of December 2011, the new optics have seen the first test beam and thorough hot commissioning will be continued until May 2012, since the ESRF shuts down for a major upgrade from December 2011 to April 2012. We expect that we will be ready for user operation from June 2012 on, with a better beamline than ever. The beamline staff would like to thank all partners, research groups and organizations who supported the beamline during the last 24 months. Special thanks to the FZD management, the CRG office of the ESRF with Axel Kaprolat as liaison officer and Eric Dettona as lead technician, and to the ESRF safety group members, Paul Berkvens, Patrick Colomp and Yann Pira.
4

A Mini-PET beamline for optimized proton delivery to the ISOTRACE™ target system

Dehnel, M. P., Jackle, P., Potkins, D., Stewart, T., Boudreault, G., Jones, T., Philpott, C. January 2015 (has links)
Introduction The ISOTRACE™ Super-Conducting Cyclotron is PMB-Alcen’s redeveloped and modernized version of Oxford Instrument’s OSCAR superconducting cyclotron [1]. Its extracted 80+ mi-croamperes of 12 MeV protons are used for the production of PET radioisotopes. Following the philosophy of Dickie, Stevenson, Szlavik [2] for minimizing dose to personnel, and as developed by Dehnel et al [3,4], and Stokely et al [5], the ISOTRACE™ shall utilize an innovative, light-weight, integrated and self-supporting Mini-Beamline. This permits the relatively high residual radiation fields around PET targets to be moved ~1 metre away from the cyclotron, and facilitates the use of local shielding (around the targets) that limits prompt gammas and neutrons, but more importantly attenuates the residual target radiation, so that maintenance/research staff can work on the cyclotron in a relatively low activity environment. In addition, the mini-beamline for PET utilizes a compound quadrupole/steerer doublet that permits active and dynamic focusing/steering of the extracted proton beam for optimized production and minimized losses [3], so it improves on the successful work of Theroux et al [6]. The integrated beamline unit is extremely small, so that it is very unlike bulky traditional PET and SPECT beamlines that require substantial support structures, such as described by Dehnel in [7,8]. Material and Methods The ISOTRACE™ cyclotron is pictured in FIG. 1. The exit port flange and gate valve to which the integrated mini-beamline for PET shall be mounted is shown. Immediately upstream of the exit port, hidden from view, is a 4 jaw collimator (called BPI for Beam Position Indicator) with spilled beam current readbacks to the control system. TABLE 1 shows the nominal beam emittance and Twiss parameter values at the exit port flange location. This ion-optical information is necessary to simulate ion beam transport, develop the mini-beamline, and determine a nominal tune (i.e. magnet settings). Results and Conclusion TABLE 2 shows the ion-optical system parameters. FIGS. 2 and 3 show the horizontal and vertical beam profiles. The Horizontally focusing Quadrupole magnet (HQ), and Vertically focusing Quadrupole magnet (VQ) aperture diameter, 33 mm, was chosen to give sufficient beam acceptance. The focusing strength is a function of BL, so the effective length, L = 150 mm, was chosen to ensure Bmax less than 0.3 Tesla, while keeping overall magnet mass down. The quad-rupole magnets are fitted with water-cooled compound coils in which the copper/mylar strip wound portion of each coil is a winding for the quadrupole focusing function, and the wire wound portion is for the steering function. To increase beam acceptance and provide additional section strength for the pipe support function, the internal aperture of the low-activation aluminium beam pipe and the external shape are in the shape of a cross. FIG. 4 shows the beam crosssection at the mid-point of the downstream quadrupole magnet, and illustrates the additional acceptance as compared to a round beampipe. In order to machine the interior profile, the pipe is comprised of two premachined pieces that are friction stirwelded together. FIG. 5 is an isometric of the mini-beamline for PET. The four upstream HQ compound coils are excited with a 75A power supply for the horizontally focusing quadrupole magnet function, and a ± 10A power supply for a vertical steering function. The same power supplies are used for the four downstream VQ compound coils for the purpose of a vertically focusing quadrupole magnet function and horizontal steering function.
5

Annual Report 2009/10 Rossendorf Beamline at ESRF (ROBL-CRG)

Scheinost, Andreas, Baehtz, Carsten January 2011 (has links)
The Rossendorf Beamline (ROBL) - located at BM20 of the European Synchrotron Radiation Facility (ESRF) in Grenoble, France - is in operation since 1998. This 7th report covers the period from January 2009 to December 2010. In these two years, 67 peer- reviewed papers have been published based on experiments done at the beamline, more than in any biannual period before. Six highlight reports have been selected for this report to demonstrate the scientific strength and diversity of the experiments performed on the two end-stations of the beamline, dedicated to Radiochemistry (RCH) and Materials Research (MRH). The beamtime was more heavily overbooked than ever before, with an acceptance rate of only 25% experiments. We would like to thank our external proposal review members, Prof. Andre Maes (KU Leuven, Belgium), Prof. Laurent Charlet (UJF Grenoble, France), Dr. Andreas Leinweber (MPI Metallforschung, Stuttgart, Germany), Prof. David Rafaja (TU Bergakademie Freiberg, Germany), Prof. Dirk Meyer (TU Dresden, Germany), who evaluated the inhouse proposals in a thorough manner, thereby ensuring that beamtime was distributed according to scientific merit. The period was not only characterized by very successful science, but also by intense work on the optics upgrade. In spring 2009, a workshop was held at ROBL, assembling beamline experts from German, Spanish and Swiss synchrotrons, to evaluate the best setup for the new optics. These suggestions was used to prepare the call for tender published in July 2009. From the tender acceptance in November 2009 on, a series of design review meetings and factory acceptance tests followed. Already in July 2010, the first piece of equipment was delivered, the new double-crystal, double-multilayer monochromator. The disassembly of the old optics components started end of July, 2011, followed by the installation of the new components. As of December 2011, the new optics have seen the first test beam and thorough hot commissioning will be continued until May 2012, since the ESRF shuts down for a major upgrade from December 2011 to April 2012. We expect that we will be ready for user operation from June 2012 on, with a better beamline than ever. The beamline staff would like to thank all partners, research groups and organizations who supported the beamline during the last 24 months. Special thanks to the FZD management, the CRG office of the ESRF with Axel Kaprolat as liaison officer and Eric Dettona as lead technician, and to the ESRF safety group members, Paul Berkvens, Patrick Colomp and Yann Pira.
6

Beamline-Instrumentierung und Experimentautomatisierung fuer ROBL an der ESRF/Grenoble (F)

Brendler, Vinzenz, Claussner, Juergen, Proehl, Dieter, Reichel, Peter, Matz, Wolfgang, Dienel, Siegfried, Reich, Tobias, Funke, Harald, Schell, Norbert, Strauch, Udo, Berberich, Florian, Oehme, Winfried, Hennig, Christoph, Prokert, Friedrich, Neumann, Wolfgang, Krug, Hans, Bernhard, Gert 31 March 2010 (has links) (PDF)
Durch das Forschungszentrum Rossendorf wurde in den Jahren 1996-1998 ein eigenes Strahlrohr fuer Experimente mit Synchrotronstrahlung an der ESRF (European Synchrotron Radioation Facility) in Grenoble/Frankreich aufgebaut. Das Strahlrohr verfuegt ueber zwei alternativ nutzbare Messplaetze fuer die Untersuchung von radioaktiven Proben mittels Roentgenabsorptionsspektroskopie und fuer Materialstrukturuntersuchungen mit Roentgendiffraktion. Der Bericht konzentriert sich auf die Arbeiten, die fuer die Steuerung der Optik und die Nutzung der Messplaetze hinsichtlich der Elektronik, Rechentechnik und Software erforderlich waren. Nach einer Beschreibung der Randbedingungen und einer Kurzcharakteristik der geraetetechnischen Basis werden wichtige Hardwarekomponenten fuer die Instrumentierung der Systeme vorgestellt. Die rechentechnische Basis wird anschliessend beschrieben. Die angewendeten Software-Grundprinzipien werden erlaeutert und diskutiert sowie an einigen Applikationen beispielhaft verdeutlicht. Abschliessend werden spezifische Probleme bei der Programmierung von Applikationen mit grafischer Bedienoberflaeche in Verbindung mit Geraetezugriffen behandelt. Tabellen, in denen die benutzten Hardware-Module und die Softwarekomponenten zusammengestellt sind, ermoeglichen einen Ueberblick ueber das Gesamtsystem. Das Literaturverzeichnis dient als Leitfaden fuer die Detaildokumentationen.
7

Beamline-Instrumentierung und Experimentautomatisierung fuer ROBL an der ESRF/Grenoble (F)

Brendler, Vinzenz, Claussner, Juergen, Proehl, Dieter, Reichel, Peter, Matz, Wolfgang, Dienel, Siegfried, Reich, Tobias, Funke, Harald, Schell, Norbert, Strauch, Udo, Berberich, Florian, Oehme, Winfried, Hennig, Christoph, Prokert, Friedrich, Neumann, Wolfgang, Krug, Hans, Bernhard, Gert January 2000 (has links)
Durch das Forschungszentrum Rossendorf wurde in den Jahren 1996-1998 ein eigenes Strahlrohr fuer Experimente mit Synchrotronstrahlung an der ESRF (European Synchrotron Radioation Facility) in Grenoble/Frankreich aufgebaut. Das Strahlrohr verfuegt ueber zwei alternativ nutzbare Messplaetze fuer die Untersuchung von radioaktiven Proben mittels Roentgenabsorptionsspektroskopie und fuer Materialstrukturuntersuchungen mit Roentgendiffraktion. Der Bericht konzentriert sich auf die Arbeiten, die fuer die Steuerung der Optik und die Nutzung der Messplaetze hinsichtlich der Elektronik, Rechentechnik und Software erforderlich waren. Nach einer Beschreibung der Randbedingungen und einer Kurzcharakteristik der geraetetechnischen Basis werden wichtige Hardwarekomponenten fuer die Instrumentierung der Systeme vorgestellt. Die rechentechnische Basis wird anschliessend beschrieben. Die angewendeten Software-Grundprinzipien werden erlaeutert und diskutiert sowie an einigen Applikationen beispielhaft verdeutlicht. Abschliessend werden spezifische Probleme bei der Programmierung von Applikationen mit grafischer Bedienoberflaeche in Verbindung mit Geraetezugriffen behandelt. Tabellen, in denen die benutzten Hardware-Module und die Softwarekomponenten zusammengestellt sind, ermoeglichen einen Ueberblick ueber das Gesamtsystem. Das Literaturverzeichnis dient als Leitfaden fuer die Detaildokumentationen.
8

Radiotherapy Beamline Design for Laser-driven Proton Beams

Masood, Umar 10 October 2019 (has links)
Motivation: Radiotherapy is an important modality in cancer treatment commonly using photon beams from compact electron linear accelerators. However, due to the inverse depth dose profile (Bragg peak) with maximum dose deposition at the end of their path, proton beams allow a dose escalation within the target volume and reduction in surrounding normal tissue. Up to 20% of all radiotherapy patients could benefit from proton therapy (PT). Conventional accelerators are utilized to obtain proton beams with therapeutic energies of 70 – 250 MeV. These beams are then transported to the patient via magnetic transferlines and a rotatable beamline, called gantry, which are large and bulky. PT requires huge capex, limiting it to only a few big centres worldwide treating much less than 1% of radiotherapy patients. The new particle acceleration by ultra-intense laser pulses occurs on micrometer scales, potentially enabling more compact PT facilities and increasing their widespread. These laser-accelerated proton (LAP) bunches have been observed recently with energies of up to 90 MeV and scaling models predict LAP with therapeutic energies with the next generation petawatt laser systems. Challenges: Intense pulses with maximum 10 Hz repetition rate, broad energy spectrum, large divergence and short duration characterize LAP beams. In contrast, conventional accelerators generate mono-energetic, narrow, quasi-continuous beams. A new multifunctional gantry is needed for LAP beams with a capture and collimation system to control initial divergence, an energy selection system (ESS) to filter variable energy widths and a large acceptance beam shaping and scanning system. An advanced magnetic technology is also required for a compact and light gantry design. Furthermore, new dose deposition models and treatment planning systems (TPS) are needed for high quality, efficient dose delivery. Materials and Methods: In conventional dose modelling, mono-energetic beams with decreasing energies are superimposed to deliver uniform spread-out Bragg peak (SOBP). The low repetition rate of LAP pulses puts a critical constraint on treatment time and it is highly inefficient to utilize conventional dose models. It is imperative to utilize unique LAP beam properties to reduce total treatment times. A new 1D Broad Energy Assorted depth dose Deposition (BEAD) model was developed. It could deliver similar SOBP by superimposing several LAP pulses with variable broad energy widths. The BEAD model sets the primary criteria for the gantry, i.e. to filter and transport pulses with up to 20 times larger energy widths than conventional beams for efficient dose delivery. Air-core pulsed magnets can reach up to 6 times higher peak magnetic fields than conventional iron-core magnets and the pulsed nature of laser-driven sources allowed their use to reduce the size and weight of the gantry. An isocentric gantry was designed with integrated laser-target assembly, beam capture and collimation, variable ESS and large acceptance achromatic beam transport. An advanced clinical gantry was designed later with a novel active beam shaping and scanning system, called ELPIS. The filtered beam outputs via the advanced gantry simulations were implemented in an advanced 3D TPS, called LAPCERR. A LAP beam gantry and TPS were brought together for the first time, and clinical feasibility was studied for the advanced gantry via tumour conformal dose calculations on real patient data. Furthermore, for realization of pulsed gantry systems, a first pulsed beamline section consisting of prototypes of a capturing solenoid and a sector magnet was designed and tested at tandem accelerator with 10MeV pulsed proton beams. A first air-core pulsed quadrupole was also designed. Results: An advanced gantry with the new ELPIS system was designed and simulated. Simulated results show that achromatic beams with actively selectable beam sizes in the range of 1 – 20 cm diameter with selectable energy widths ranging from 19 – 3% can be delivered via the advanced gantry. ELPIS can also scan these large beams to a 20 × 10 cm2 irradiation field. This gantry is about 2.5 m in height and about 3.5 m in length, which is about 4 times smaller in volume than the conventional PT gantries. The clinical feasibility study on a head and neck tumour patient shows that these filtered beams can deliver state-of-the-art 3D intensity modulated treatment plans. Experimental characterization of a prototype pulsed beamline section was performed successfully and the synchronization of proton pulse with peak magnetic field in the individual magnets was established. This showed the practical applicability and feasibility of pulsed beamlines. The newly designed pulsed quadrupole with three times higher field gradients than iron-core quadrupoles is already manufactured and will be tested in near future. Conclusion: The main hurdle towards laser-driven PT is a laser accelerator providing beams of therapeutic quality, i.e. energy, intensity, stability, reliability. Nevertheless, the presented advanced clinical gantry design presents a complete beam transport solution for future laser-driven sources and shows the prospect and limitations of a compact laser-driven PT facility. Further development in the LAP-CERR is needed as it has the potential to utilize advanced beam controls from the ELPIS system and optimize doses on the basis of advanced dose schemes, like partial volume irradiation, to bring treatment times further down. To realize the gantry concept, further research, development and testing in higher field and higher (up to 10 Hz) repetition rate pulsed magnets to cater therapeutic proton beams is crucial.
9

Design of a high performance soft x-ray emission spectrometer for the REIXS beamline at the Canadian Light Source

Muir, David Ian 28 November 2006
The optical design of a soft X-ray (90-1100~eV) emission spectrometer for the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline to be implemented at the CLS is presented. An overview of soft X-ray optical theory as it relates to diffraction gratings is given. The initial constraints and the process that led to this design are outlined. Techniques and software tools that were developed, using ray-tracing and diffraction grating efficiency calculations, are discussed. The analysis completed with these tools to compare existing soft X-ray emission spectrometer designs is presented. Based on this analysis, a new design with superior performance for this application is proposed and reviewed. This design employs Rowland circle geometry to achieve a resolving power in excess of 2,500 in the range of interest. In addition, a novel design is proposed for a larger extremely high resolution spectrometer which will provide resolving powers exceeding 10,000 throughout the higher end of this range. A review is given of research into the components, manufacturing techniques and tolerances that will be required to produce this spectrometer.
10

Design of a high performance soft x-ray emission spectrometer for the REIXS beamline at the Canadian Light Source

Muir, David Ian 28 November 2006 (has links)
The optical design of a soft X-ray (90-1100~eV) emission spectrometer for the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline to be implemented at the CLS is presented. An overview of soft X-ray optical theory as it relates to diffraction gratings is given. The initial constraints and the process that led to this design are outlined. Techniques and software tools that were developed, using ray-tracing and diffraction grating efficiency calculations, are discussed. The analysis completed with these tools to compare existing soft X-ray emission spectrometer designs is presented. Based on this analysis, a new design with superior performance for this application is proposed and reviewed. This design employs Rowland circle geometry to achieve a resolving power in excess of 2,500 in the range of interest. In addition, a novel design is proposed for a larger extremely high resolution spectrometer which will provide resolving powers exceeding 10,000 throughout the higher end of this range. A review is given of research into the components, manufacturing techniques and tolerances that will be required to produce this spectrometer.

Page generated in 0.0296 seconds