Cyclotrons2013 - List of Keywords (focusing)

Paper	Title	Other Keywords	Page
MOPPT019	A Compact, GeV, High-Intensity (CW) Racetrack FFAG	cyclotron, acceleration, extraction, synchrotron	73
	C. Johnstone Fermilab, Batavia, Illinois, USA M. Berz, K. Makino MSU, East Lansing, Michigan, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	High-intensity and energy compact proton accelerators, especially those requiring milliamp currents, imply both CW operation and high acceleration gradients to mitigate losses. Above a few hundred MeV, losses must be under a per cent to avoid massive shielding and unmanageable activation. As relativistic energies are approached, the orbit separation on consecutive acceleration turns decreases for isochronous performance and to achieve higher acceleration gradients and orbit separation, RF modules must be employed rather than Dees, resulting in the larger separated-sector cyclotron footprint. However, the addition of strong focusing – with reversed gradients to capture both transverse planes – to conventional cyclotron fields promote inclusion of long synchrotron-like straight sections and implementation of high-gradient RF, even SCRF. The nsFFAG design has evolved into a a recirculating linear accelerator form with FFAG arcs. An ultra-compact, 0.2 – 1 GeV RLA FFAG design will be discussed (with a 3m x 5-6m footprint) that uses SC RF cryomodules achieving complete orbit separation at extraction and CW operation.

MOPPT024	Radial-Sector Cyclotrons with Different Hill and Valley Field Profiles	cyclotron, proton, betatron, TRIUMF	82
	M.K. Craddock UBC & TRIUMF, Vancouver, British Columbia, Canada
	A new class of isochronous cyclotron is described in which more general radial field profiles B(r) are allowed than the simple proportionality to total energy found in conventional radial- and spiral-sector cyclotrons. Isochronism is maintained by using different field profiles in the hills and valleys. Suitably chosen profiles will produce high flutter factors and significant alternating-gradient focusing, enabling vertical focusing to be maintained up to 1 GeV or more using radial rather than spiral sectors.

MO3PB01	An Inverse Cyclotron for Muon Cooling	extraction, cyclotron, injection, simulation	97
	T.L. Hart, D.J. Summers UMiss, University, Mississippi, USA
	The production of intense high energy muon beams for muon colliders is an active area of interest due to the muon's large mass and pointlike structure. The muon production and the subsequent preparation into a beam are challenging due to the large emittance of the initial beam and the short muon lifetime. Most muon cooling channels being developed are single-pass structures due to the difficulty of injecting large emittance beams into a circular device. Inverse cyclotrons can potentially solve the injection problem using single turn energy loss injection and also reduce the muon beam emittance by a large factor. An end-to-end simulation of an inverse cyclotron for muon cooling is presented performed with G4Beamline, a GEANT-based particle tracking simulation program. Muons are collected in a central trap and then all ejected together.
	Slides MO3PB01 [1.747 MB]

MO4PB02	The IBA Superconducting Synchrocyclotron Project S2C2	extraction, cyclotron, ion-source, ion	115
	W.J.G.M. Kleeven, M. Abs, E. Forton, S. Henrotin, Y. Jongen, V. Nuttens, Y. Paradis, E.E. Pearson, S. Quets, P. Verbruggen, S. Zaremba, J. van de Walle IBA, Louvain-la-Neuve, Belgium M. Conjat, J. Mandrillon, P. Mandrillon AIMA, Nice, France
	In 2009 IBA decided to start the development of a compact superconducting synchrocyclotron as a proton-source for the small footprint proton therapy system called Proteus One ®. The cyclotron has been completely designed and constructed and is currently under commissioning at the IBA factory. Its design and commissioning results will be presented.
	Slides MO4PB02 [21.175 MB]

TUPPT015	A Center Region Upgrade of the LBNL 88-Inch Cyclotron	cyclotron, ion, injection, ion-source	186
	K. Yoshiki Franzen, J.Y. Benitez, M.K. Covo, A. Hodgkinson, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, M.M. Strohmeier, D.S. Todd LBNL, Berkeley, California, USA D. Leitner NSCL, East Lansing, Michigan, USA
	This paper describes the design and results of an upgraded cyclotron center region in which a mirror field type inflector was replaced by a spiral inflector. The main goals of the design were a) to facilitate injection at higher energies in order to improve transmission efficiency and b) to reduce down-time due to the need of replacing mirror inflector wires which rapidly break when exposed to high beam currents. The design was based on a detailed model of the spiral inflector and matching center region electrodes using AMaze, a 3D finite element suite of codes. Tests showed promising results indicating that the 88-Inch cyclotron will be able to provide a 2.0 pμA beam of 250 MeV 48Ca ions.

TUPSH014	An Integrated Self-Supporting Mini-Beamline for PET Cyclotrons	cyclotron, target, controls, radiation	251
	M.P. Dehnel, D.E. Potkins, T.M. Stewart D-Pace, Nelson, British Columbia, Canada
	Funding: SR&ED A commercial fluorine-18 water-target can now handle 150 μA of 10-19 MeV proton current. The days of a few tens of micro-amperes bombarding a PET target with low residual activity on a self-shielded cyclotron are over. Now an integrated self-supporting mini-beamline is essential for safe, optimized and reliable operation of PET cyclotrons. The high levels of prompt/residual radiation are moved (~1 m) away from the cyclotron so that local-shielding can be placed around the target/selector assembly, which minimizes cyclotron component damage due to prompt neutrons/gammas, and ensures the high residual target radiation is attenuated, so maintenance personnel can work on the cyclotron in a “cool” environment. Beam diagnostic readbacks from baffles/collimators provide steering and focusing control of the beam. This "plug-n-play" beamline is an integrated self-supporting unit cantilevered from the cyclotron. The single aluminum sub-structure acts as mounting flange, support structure, beampipe, and magnet registration device. A diamond-shaped vacuum envelope through the compound quadrupole/steering magnets results in maximum beam throughput and optimization.

TU4PB03	Superconducting Beam Transport Channel for a Strong-Focusing Cyclotron	dipole, cyclotron, quadrupole, beam-transport	278
	K.E. Melconian, S. Assadi, K.C. Damborsky, J.N. Kellams, P.M. McIntyre, N. Pogue, A. Sattarov Texas A&M University, College Station, Texas, USA
	Funding: The Mitchell Family Foundation and Texas ASE Fund A superconducting strong focusing cyclotron is being developed for high current applications. Alternating-gradient focusing is provided by an array of ~ 6T/m superconducting beam transport channels which lie in the sectors along the arced beam trajectory of each orbit of the cyclotron. The ~1T sector dipoles, corrector dipoles, and Panofsky type quadrupoles utilize MgB2 superconductor operating in the range 15-20 K. The quadrupole windings make it possible to produce strong focusing of the transverse phase space throughout acceleration. The trim dipole makes it possible to maintain isochronicity and to open the orbit spacing at injection and extraction. The design, development and prototype progress will be presented.
	Slides TU4PB03 [4.020 MB]

WE1PB02	The Rutgers Cyclotron: Placing Student's Careers on Target	cyclotron, ion, simulation, proton	291
	K.J. Ruisard Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA G.A. Hine, T.W. Koeth UMD, College Park, Maryland, USA A.J. Rosenberg Stanford University, Stanford, California, USA
	The Rutgers 12” Cyclotron is an educational tool used to introduce students to the multifaceted field of accelerator physics. Since its inception, the cyclotron has been under continuous development and is currently incorporated into the modern physics lab course at Rutgers University, as a semester-long mentored project. Students who participate in the cyclotron project receive an introduction to topics such as beam physics, high voltage power, RF systems, vacuum systems and magnet operation. Student projects have led to three different focusing pole geometries, including, most recently, a spiral edged azimuthally varying field (AVF) configuration. The Rutgers Cyclotron is often a student’s first encounter with an accelerator, and has inspired careers in accelerator physics.
	Slides WE1PB02 [14.090 MB]

WE1PB04	A Novel Optical Method for Measuring Beam Phase and Width in the Rutgers 12-Inch Cyclotron	cyclotron, ion, simulation, proton	299
	J.L. Gonski, S. Burcher, T.W. Koeth, J.E. Krutzler, S. Lazarov Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA J. Beaudoin UMD, College Park, Maryland, USA
	We present an experimental longitudinal measurement of beam and phase slippage as a function of magnetic field deviation in a weak focusing field, using proton acceleration data from the Rutgers 12-inch cyclotron. A gated camera was used to determine beam arrival time from the radiation emitted by a fast ZnO:Ga doped phosphor target when struck by accelerated protons. Images integrated light emitted in 9 degree increments over a full 360-degree RF cycle. Analysis of relative image brightness allowed for the successful acquisition of relative phase shift and azimuthal beam width over several magnetic field strengths. Theoretical predictions and simulation via Poisson Superfish and SIMION software show good agreement with data, validating the optical method for qualitative measurements. This new method is independent of dee voltage and allows for measurements to be taken in the central region of the cyclotron, where other electrically based methods of measurement are challenging due to high RF electric fields. Such characteristics validate the use of gated camera imaging for cyclotron research, and motivate future refinement of this technique for a variety of studies.
	Slides WE1PB04 [3.662 MB]

WE2PB03	Transverse-Longitudinal Coupling by Space Charge in Cyclotrons	emittance, space-charge, cyclotron, simulation	315
	C. Baumgarten PSI, Villigen PSI, Switzerland
	Based on a linear space charge model and on the results of PIC-simulations with OPAL, we analyze the conditions under which space charge forces support bunch compactness in high intensity cyclotrons and/or FFAGs. For this purpose we compare the simulated emittance increase and halo formation for different matched and mismatched particle distributions injected into a separate sector cyclotron with different phase curves.
	Slides WE2PB03 [3.187 MB]

WEPPT004	Feasibility Study of Intense Beam Matching at the Spiral Inflector Using Elliptical Solenoid	solenoid, emittance, space-charge, injection	326
	A. Goswami, V.S. Pandit, P. Sing Babu VECC, Kolkata, India
	Simulation results on a spiral inflector for compact cyclotron, indicate that convergent phase ellipses with different orientations in x and y planes and a comparatively smaller width in the y plane gives better beam transmission through the inflector. In order to transform the axisymmetric beam to a non-axisymmetric beam for matching at the entrance of the inflector one needs either an elliptical solenoid or a quadrupole doublet. The injection system of 10MeV-5mA proton cyclotron being developed at VECC consists of a 2.45GHz (80keV) microwave ion source and two solenoids to transport and match the beam at the spiral inflector. Due to space constraint we have planned to use an elliptical solenoid just before the spiral inflector for transverse matching of the beam. In this work the beam optical properties of an elliptical solenoid have been studied, including the effect of space charge. An envelope model based on the canonical description of motion has been developed and utilized to study the feasibility of using an elliptical solenoid for transverse matching of a space charge dominated beam to the acceptance of a spiral inflector.

WEPPT025	Beam Physics Demonstrations with the Rutgers 12-Inch Cyclotron	cyclotron, ion, betatron, resonance	369
	T.W. Koeth UMD, College Park, Maryland, USA
	The Rutgers 12-Inch Cyclotron is a research grade accelerator dedicated to undergraduate education.[1] From its inception, it has been intended for instruction and has been designed to demonstrate classic beam physics phenomena. The machine is easily reconfigured, allowing experiments to be designed and performed within one academic semester. Our cyclotron gives students a hands-on opportunity to operate an accelerator and directly observe many fundamental beam physics concepts, including axial and radial betatron motion, destructive resonances, weak and azimuthally varying field (AVF) focusing schemes, DEE voltage effects, and more.

WE3PB02	Improvement of the Current Stability from the TRIUMF Cyclotron	cyclotron, TRIUMF, injection, space-charge	414
	T. Planche, R.A. Baartman, Y.-N. Rao TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	The ν_r=3/2 resonance, driven by the third harmonic of the magnetic gradient errors, causes modulation of the radial beam density in the TRIUMF cyclotron. Since extraction is by H^- stripping, this modulation induces unwanted fluctuations of the current split between the two high-energy beam lines. To compensate field imperfections, the cyclotron has sets of harmonic correction coils at different radii, each set constituted of 6 pairs of coils placed in a 6-fold symmetrical manner. The 6-fold symmetry of this layout cannot create a third harmonic of arbitrary phase, and so a single set of harmonic coils cannot provide a full correction of third harmonic errors driving the ν_r=3/2 resonance. However, the outermost two sets of harmonic correction coils are azimuthally displaced. We took advantage of it to achieve a full correction of the resonance. This greatly improved the beam current stability in the high-energy beam lines. To further improve the current stability in the high-energy beam lines, we implemented an active feedback system. This feedback system acts on the amplitude of the first harmonic Bz correction produced by outermost set of harmonic coils.
	Slides WE3PB02 [1.007 MB]

WE4PB03	Optimizing the Radioisotope Production with a Weak Focusing Compact Cyclotron	cyclotron, ion-source, ion, vacuum	429
	C. Oliver, P. Abramian, B. Ahedo, P. Arce, J.M. Barcala, J. Calero, E. Calvo, L. García-Tabarés, D. Gavela, A. Guirao, J.L. Gutiérrez, J.I. Lagares, L.M. Martinez Fresno, T. Martínez de Alvaro, E. Molina Marinas, J. Munilla, D. Obradors-Campos, F.J. Olivert, J.M. Perez Morales, I. Podadera, E. Rodriguez, L. Sanchez, F. Sansaloni, F. Toral, C. Vázquez CIEMAT, Madrid, Spain
	A classical weak focusing cyclotron can result in a simple and compact design for the radioisotope production for medical applications. Two main drawbacks arise from this type of machine. The energy limit imposed by the non RF-particle isochronism requires a careful design of the acceleration process, resulting in challenging requirements for the RF system. On the other hand, the weak focusing forces produced by the slightly decreasing magnetic field make essential to model the central region of the machine to improve the electric focalization with a reasonable phase acceptance. A complete analysis of the different beam losses, including vacuum stripping, has been performed. The main cyclotron parameters have been obtained by balancing the maximum energy we can obtain and the maximum beam transmission, resulting in an optimum radioisotope production.
	Slides WE4PB03 [2.904 MB]

Paper

Title

Other Keywords

Page

MOPPT019

A Compact, GeV, High-Intensity (CW) Racetrack FFAG

cyclotron, acceleration, extraction, synchrotron

73

C. Johnstone
Fermilab, Batavia, Illinois, USA
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

High-intensity and energy compact proton accelerators, especially those requiring milliamp currents, imply both CW operation and high acceleration gradients to mitigate losses. Above a few hundred MeV, losses must be under a per cent to avoid massive shielding and unmanageable activation. As relativistic energies are approached, the orbit separation on consecutive acceleration turns decreases for isochronous performance and to achieve higher acceleration gradients and orbit separation, RF modules must be employed rather than Dees, resulting in the larger separated-sector cyclotron footprint. However, the addition of strong focusing – with reversed gradients to capture both transverse planes – to conventional cyclotron fields promote inclusion of long synchrotron-like straight sections and implementation of high-gradient RF, even SCRF. The nsFFAG design has evolved into a a recirculating linear accelerator form with FFAG arcs. An ultra-compact, 0.2 – 1 GeV RLA FFAG design will be discussed (with a 3m x 5-6m footprint) that uses SC RF cryomodules achieving complete orbit separation at extraction and CW operation.

MOPPT024

Radial-Sector Cyclotrons with Different Hill and Valley Field Profiles

cyclotron, proton, betatron, TRIUMF

82

M.K. Craddock
UBC & TRIUMF, Vancouver, British Columbia, Canada

A new class of isochronous cyclotron is described in which more general radial field profiles B(r) are allowed than the simple proportionality to total energy found in conventional radial- and spiral-sector cyclotrons. Isochronism is maintained by using different field profiles in the hills and valleys. Suitably chosen profiles will produce high flutter factors and significant alternating-gradient focusing, enabling vertical focusing to be maintained up to 1 GeV or more using radial rather than spiral sectors.

MO3PB01

An Inverse Cyclotron for Muon Cooling

extraction, cyclotron, injection, simulation

97

T.L. Hart, D.J. Summers
UMiss, University, Mississippi, USA

The production of intense high energy muon beams for muon colliders is an active area of interest due to the muon's large mass and pointlike structure. The muon production and the subsequent preparation into a beam are challenging due to the large emittance of the initial beam and the short muon lifetime. Most muon cooling channels being developed are single-pass structures due to the difficulty of injecting large emittance beams into a circular device. Inverse cyclotrons can potentially solve the injection problem using single turn energy loss injection and also reduce the muon beam emittance by a large factor. An end-to-end simulation of an inverse cyclotron for muon cooling is presented performed with G4Beamline, a GEANT-based particle tracking simulation program. Muons are collected in a central trap and then all ejected together.

Slides MO3PB01 [1.747 MB]

MO4PB02

The IBA Superconducting Synchrocyclotron Project S2C2

extraction, cyclotron, ion-source, ion

115

W.J.G.M. Kleeven, M. Abs, E. Forton, S. Henrotin, Y. Jongen, V. Nuttens, Y. Paradis, E.E. Pearson, S. Quets, P. Verbruggen, S. Zaremba, J. van de Walle
IBA, Louvain-la-Neuve, Belgium
M. Conjat, J. Mandrillon, P. Mandrillon
AIMA, Nice, France

In 2009 IBA decided to start the development of a compact superconducting synchrocyclotron as a proton-source for the small footprint proton therapy system called Proteus One ®. The cyclotron has been completely designed and constructed and is currently under commissioning at the IBA factory. Its design and commissioning results will be presented.

Slides MO4PB02 [21.175 MB]

TUPPT015

A Center Region Upgrade of the LBNL 88-Inch Cyclotron

cyclotron, ion, injection, ion-source

186

K. Yoshiki Franzen, J.Y. Benitez, M.K. Covo, A. Hodgkinson, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, M.M. Strohmeier, D.S. Todd
LBNL, Berkeley, California, USA
D. Leitner
NSCL, East Lansing, Michigan, USA

This paper describes the design and results of an upgraded cyclotron center region in which a mirror field type inflector was replaced by a spiral inflector. The main goals of the design were a) to facilitate injection at higher energies in order to improve transmission efficiency and b) to reduce down-time due to the need of replacing mirror inflector wires which rapidly break when exposed to high beam currents. The design was based on a detailed model of the spiral inflector and matching center region electrodes using AMaze, a 3D finite element suite of codes. Tests showed promising results indicating that the 88-Inch cyclotron will be able to provide a 2.0 pμA beam of 250 MeV 48Ca ions.

TUPSH014

An Integrated Self-Supporting Mini-Beamline for PET Cyclotrons

cyclotron, target, controls, radiation

251

M.P. Dehnel, D.E. Potkins, T.M. Stewart
D-Pace, Nelson, British Columbia, Canada

Funding: SR&ED
A commercial fluorine-18 water-target can now handle 150 μA of 10-19 MeV proton current. The days of a few tens of micro-amperes bombarding a PET target with low residual activity on a self-shielded cyclotron are over. Now an integrated self-supporting mini-beamline is essential for safe, optimized and reliable operation of PET cyclotrons. The high levels of prompt/residual radiation are moved (~1 m) away from the cyclotron so that local-shielding can be placed around the target/selector assembly, which minimizes cyclotron component damage due to prompt neutrons/gammas, and ensures the high residual target radiation is attenuated, so maintenance personnel can work on the cyclotron in a “cool” environment. Beam diagnostic readbacks from baffles/collimators provide steering and focusing control of the beam. This "plug-n-play" beamline is an integrated self-supporting unit cantilevered from the cyclotron. The single aluminum sub-structure acts as mounting flange, support structure, beampipe, and magnet registration device. A diamond-shaped vacuum envelope through the compound quadrupole/steering magnets results in maximum beam throughput and optimization.

TU4PB03

Superconducting Beam Transport Channel for a Strong-Focusing Cyclotron

dipole, cyclotron, quadrupole, beam-transport

278

K.E. Melconian, S. Assadi, K.C. Damborsky, J.N. Kellams, P.M. McIntyre, N. Pogue, A. Sattarov
Texas A&M University, College Station, Texas, USA

Funding: The Mitchell Family Foundation and Texas ASE Fund
A superconducting strong focusing cyclotron is being developed for high current applications. Alternating-gradient focusing is provided by an array of ~ 6T/m superconducting beam transport channels which lie in the sectors along the arced beam trajectory of each orbit of the cyclotron. The ~1T sector dipoles, corrector dipoles, and Panofsky type quadrupoles utilize MgB2 superconductor operating in the range 15-20 K. The quadrupole windings make it possible to produce strong focusing of the transverse phase space throughout acceleration. The trim dipole makes it possible to maintain isochronicity and to open the orbit spacing at injection and extraction. The design, development and prototype progress will be presented.

Slides TU4PB03 [4.020 MB]

WE1PB02

The Rutgers Cyclotron: Placing Student's Careers on Target

cyclotron, ion, simulation, proton

291

K.J. Ruisard
Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
G.A. Hine, T.W. Koeth
UMD, College Park, Maryland, USA
A.J. Rosenberg
Stanford University, Stanford, California, USA

The Rutgers 12” Cyclotron is an educational tool used to introduce students to the multifaceted field of accelerator physics. Since its inception, the cyclotron has been under continuous development and is currently incorporated into the modern physics lab course at Rutgers University, as a semester-long mentored project. Students who participate in the cyclotron project receive an introduction to topics such as beam physics, high voltage power, RF systems, vacuum systems and magnet operation. Student projects have led to three different focusing pole geometries, including, most recently, a spiral edged azimuthally varying field (AVF) configuration. The Rutgers Cyclotron is often a student’s first encounter with an accelerator, and has inspired careers in accelerator physics.

Slides WE1PB02 [14.090 MB]

WE1PB04

A Novel Optical Method for Measuring Beam Phase and Width in the Rutgers 12-Inch Cyclotron

cyclotron, ion, simulation, proton

299

J.L. Gonski, S. Burcher, T.W. Koeth, J.E. Krutzler, S. Lazarov
Rutgers University, The State University of New Jersey, Piscataway, New Jersey, USA
J. Beaudoin
UMD, College Park, Maryland, USA

We present an experimental longitudinal measurement of beam and phase slippage as a function of magnetic field deviation in a weak focusing field, using proton acceleration data from the Rutgers 12-inch cyclotron. A gated camera was used to determine beam arrival time from the radiation emitted by a fast ZnO:Ga doped phosphor target when struck by accelerated protons. Images integrated light emitted in 9 degree increments over a full 360-degree RF cycle. Analysis of relative image brightness allowed for the successful acquisition of relative phase shift and azimuthal beam width over several magnetic field strengths. Theoretical predictions and simulation via Poisson Superfish and SIMION software show good agreement with data, validating the optical method for qualitative measurements. This new method is independent of dee voltage and allows for measurements to be taken in the central region of the cyclotron, where other electrically based methods of measurement are challenging due to high RF electric fields. Such characteristics validate the use of gated camera imaging for cyclotron research, and motivate future refinement of this technique for a variety of studies.

Slides WE1PB04 [3.662 MB]

WE2PB03

Transverse-Longitudinal Coupling by Space Charge in Cyclotrons

emittance, space-charge, cyclotron, simulation

315

C. Baumgarten
PSI, Villigen PSI, Switzerland

Based on a linear space charge model and on the results of PIC-simulations with OPAL, we analyze the conditions under which space charge forces support bunch compactness in high intensity cyclotrons and/or FFAGs. For this purpose we compare the simulated emittance increase and halo formation for different matched and mismatched particle distributions injected into a separate sector cyclotron with different phase curves.

Slides WE2PB03 [3.187 MB]

WEPPT004

Feasibility Study of Intense Beam Matching at the Spiral Inflector Using Elliptical Solenoid

solenoid, emittance, space-charge, injection

326

A. Goswami, V.S. Pandit, P. Sing Babu
VECC, Kolkata, India

Simulation results on a spiral inflector for compact cyclotron, indicate that convergent phase ellipses with different orientations in x and y planes and a comparatively smaller width in the y plane gives better beam transmission through the inflector. In order to transform the axisymmetric beam to a non-axisymmetric beam for matching at the entrance of the inflector one needs either an elliptical solenoid or a quadrupole doublet. The injection system of 10MeV-5mA proton cyclotron being developed at VECC consists of a 2.45GHz (80keV) microwave ion source and two solenoids to transport and match the beam at the spiral inflector. Due to space constraint we have planned to use an elliptical solenoid just before the spiral inflector for transverse matching of the beam. In this work the beam optical properties of an elliptical solenoid have been studied, including the effect of space charge. An envelope model based on the canonical description of motion has been developed and utilized to study the feasibility of using an elliptical solenoid for transverse matching of a space charge dominated beam to the acceptance of a spiral inflector.

WEPPT025

Beam Physics Demonstrations with the Rutgers 12-Inch Cyclotron

cyclotron, ion, betatron, resonance

369

T.W. Koeth
UMD, College Park, Maryland, USA

The Rutgers 12-Inch Cyclotron is a research grade accelerator dedicated to undergraduate education.[1] From its inception, it has been intended for instruction and has been designed to demonstrate classic beam physics phenomena. The machine is easily reconfigured, allowing experiments to be designed and performed within one academic semester. Our cyclotron gives students a hands-on opportunity to operate an accelerator and directly observe many fundamental beam physics concepts, including axial and radial betatron motion, destructive resonances, weak and azimuthally varying field (AVF) focusing schemes, DEE voltage effects, and more.

WE3PB02

Improvement of the Current Stability from the TRIUMF Cyclotron

cyclotron, TRIUMF, injection, space-charge

414

T. Planche, R.A. Baartman, Y.-N. Rao
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

The ν_r=3/2 resonance, driven by the third harmonic of the magnetic gradient errors, causes modulation of the radial beam density in the TRIUMF cyclotron. Since extraction is by H^- stripping, this modulation induces unwanted fluctuations of the current split between the two high-energy beam lines. To compensate field imperfections, the cyclotron has sets of harmonic correction coils at different radii, each set constituted of 6 pairs of coils placed in a 6-fold symmetrical manner. The 6-fold symmetry of this layout cannot create a third harmonic of arbitrary phase, and so a single set of harmonic coils cannot provide a full correction of third harmonic errors driving the ν_r=3/2 resonance. However, the outermost two sets of harmonic correction coils are azimuthally displaced. We took advantage of it to achieve a full correction of the resonance. This greatly improved the beam current stability in the high-energy beam lines. To further improve the current stability in the high-energy beam lines, we implemented an active feedback system. This feedback system acts on the amplitude of the first harmonic Bz correction produced by outermost set of harmonic coils.

Slides WE3PB02 [1.007 MB]

WE4PB03

Optimizing the Radioisotope Production with a Weak Focusing Compact Cyclotron

cyclotron, ion-source, ion, vacuum

429

C. Oliver, P. Abramian, B. Ahedo, P. Arce, J.M. Barcala, J. Calero, E. Calvo, L. García-Tabarés, D. Gavela, A. Guirao, J.L. Gutiérrez, J.I. Lagares, L.M. Martinez Fresno, T. Martínez de Alvaro, E. Molina Marinas, J. Munilla, D. Obradors-Campos, F.J. Olivert, J.M. Perez Morales, I. Podadera, E. Rodriguez, L. Sanchez, F. Sansaloni, F. Toral, C. Vázquez
CIEMAT, Madrid, Spain

A classical weak focusing cyclotron can result in a simple and compact design for the radioisotope production for medical applications. Two main drawbacks arise from this type of machine. The energy limit imposed by the non RF-particle isochronism requires a careful design of the acceleration process, resulting in challenging requirements for the RF system. On the other hand, the weak focusing forces produced by the slightly decreasing magnetic field make essential to model the central region of the machine to improve the electric focalization with a reasonable phase acceptance. A complete analysis of the different beam losses, including vacuum stripping, has been performed. The main cyclotron parameters have been obtained by balancing the maximum energy we can obtain and the maximum beam transmission, resulting in an optimum radioisotope production.

Slides WE4PB03 [2.904 MB]