Cyclotrons2013 - List of Keywords (radiation)

Paper	Title	Other Keywords	Page
MOPPT001	Status Report of the Cyclotrons C-30, CS-30 and RDS-111 at KFSHRC, Saudi Arabia	cyclotron, target, proton, controls	28
	F.M. Alrumayan, M.S. Shawoo, M. Vora King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Kingdom of Saudi Arabia
	Experience gained since the commissioning of the IBA C-30 Cyclotron at the King Faisal Specialist Hospital and Research Centre (KFSHRC) in 2010, has shown this facility to be viable entity. In addition to the C-30 Cyclotron, the facility includes two other Cyclotrons namely; the RDS-111 and the CS30 Cyclotrons. The latter has dual responsibilities; while is kept as a backup for the other Cyclotrons for radioisotopes production, it’s used for proton therapy researches and Bragg Peak measurements at that particular energy. During the commission of the C30 cyclotron, 700 uA dual beam were measured. Facility operating history, usage and radiopharmaceuticals productions are described.

MOPPT008	Present Status of Cyclotrons (NIRS-930, HM-18) at NIRS	cyclotron, proton, injection, ion	46
	S. Hojo, T. Honma, K. Katagiri, M. Nakao, A. Noda, K. Noda, A. Sugiura NIRS, Chiba-shi, Japan A.K. Komiyama, T. Okada, Y. Takahashi AEC, Chiba, Japan
	The cyclotron facility at National Institute of Radiological Science (NIRS) consists of a NIRS-930 cyclotron (Thomson-CSF AVF-930, Kb=110 MeV and Kf=90 MeV) and a small cyclotron HM-18(Sumitomo- Heavy- Industry HM-18). The NIRS-930 has been used for production of short-lived radio-pharmaceuticals for PET, research of physics, developments of particle detectors in space, and so on. The orbit of a beam in the NIRS-930 cyclotron was simulated with integrated approach to modelling of the cyclotron, including calculation of electromagnetic fields of the structural elements. And some improvements such as installation of extracted beam probe, a beam attenuator and a beam viewer in an injection beam line, were performed in the NIRS-930. The HM-18 has been used for production of short-lived radio-pharmaceuticals for PET. It allows us to accelerate H-and D- ion at fixed energies of 18 and 9 MeV, respectively. In order to improve the isochronism, a phase probe has been newly installed in the HM-18. Above improvements and operational status of the cyclotron facility are to be presented in this report.

MOPPT030	Past, Present and Future Activities for Radiation Effects Testing at JULIC/COSY	proton, simulation, neutron, ion	88
	S.K. Hoeffgen, S. Metzger FhG, Euskirchen, Germany R. Brings, O. Felden, R. Gebel, R. Maier, D. Prasuhn FZJ, Jülich, Germany M. Brugger, R. Garcia Alia CERN, Geneva, Switzerland
	The testing of radiation effects (displacement damage DD, single event effects SEE) with energetic protons for electronics used in space and accelerators is of growing importance. Setup and past experience of a dedicated test stand used by Fraunhofer INT at the JULIC cyclotron will be presented. For general DD testing and for testing SEE of the trapped protons in space, the energy of 35 MeV of the JULIC Cyclotron is usually sufficient. During solar proton events, as well as at high energy accelerators (CERN, FAIR), electronics are confronted with protons of much higher energy. Recent scientific studies have shown that for single event upsets* as well as destructive failures (e.g, single event latch-ups)** a cross section measured at energies in the tens oF one/two-hundred MeV range (e.g. PIF@PSI) can significantly underestimate the failure rate. To avoid unnecessary high safety margins there is a growing need for the opportunity to test electronics at several GeV, like the beam provided by the Cooler-Synchrotron COSY in Jülich. R. Garcia Alia et. al., accepted for publication, IEEE TNS (2013), DOI:10.1109/TNS.2013.2249096 *J. R. Schwank et al., IEEE TNS, vol. 52, pp2622 (2005)

TUPSH005	Investigation of Cyclotron Carbon Foil Lifetime in Relation to its Thickness	electron, proton, ion, cyclotron	227
	J.-W. Kim, S. Hong, J.H. Kim IBS, Daejeon, Republic of Korea Y. Choi Dongguk University, Gyeongju, Republic of Korea Y.-S. Kim Energy & Environmental System, Gyeongju, Republic of Korea
	For extracting positive hydrogen atoms from accelerated negative ones, a thin carbon foil is usually used to stripe two electrons from negative atoms, which consists of one proton and two electrons traveling together up to 70MeV proton. The kinetic energy of electron is 38.13keV at the moment of stripping. The energy loss of protons and electrons in carbon foil could be estimated by the multiplication of stopping power (dE/dz) and the foil thickness where passing through. The stopping powers were estimated with 8.5 and 7.25 MeV/(g/cm²) for the proton and electron, respectively. In cyclotron the stripper is located in a strong magnetic field of ~Tesla, which makes electrons circular motion around the foil depositing all their kinetic energies into it. In this study, three different carbon foil thicknesses (200, 400, and 800 ug/cm²) were employed to investigate the correlation of foil temperature and their lifetime for the case of 1mA proton extraction. We are aiming the lifetime of a stripper foil to be as long as 2 weeks for irradiating protons onto an ISOL target. An effective lifetime of foils will be discussed as a function of a foil peak temperature.

TUPSH014	An Integrated Self-Supporting Mini-Beamline for PET Cyclotrons	cyclotron, target, focusing, controls	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.

TUPSH016	Trim Coil Unbalance of the 88-Inch Cyclotron	cyclotron, ion, power-supply, injection	254
	M. Kireeff Covo, B. Bingham, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, A. Ratti, M.M. Strohmeier, D.S. Todd LBNL, Berkeley, California, USA K.Y. Franzen Mevion, Littleton, Massachusetts, USA
	Funding: Work supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. Department of Energy under Contract DE-AC02-05CH11231. The 88-inch cyclotron Dee probe shows large losses inside the radius of 20 cm and suggests problems in the ion beam injection. The current of the top and bottom innermost trim coil 1 is unbalanced to study effects of the axial injection displacement. A new beam profile monitor images the ion beam bunches, turn by turn, and the beam center of mass position is measured. The technique allows increasing the beam transmission through the cyclotron.

WEPSH007	Radiochromic Film as a Dosimetric Tool for Low Energy Proton Beams	proton, photon, cyclotron, ion	397
	S. Devic, S. Aldelaijan, F.M. Alrumayan, F. Alzorkani, B.M. Moftah, M. Shehadeh King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Kingdom of Saudi Arabia
	Funding: King Abdulaziz City for Science and Technology (KACST), Grant No 11-BIO1428-20 EBT3 and HDV2 GAFCHROMICTM films were tested for dose measurements at a 26.5 MeV and 6 mm Bragg peak proton beam. Beam output was calibrated using IAEA TRS-398 reference dosimetry protocol with calibrated chamber in water. Films were calibrated in terms of dose to water by exposing calibration film pieces within a solid water phantom at depth of 3 mm. EBT3 films were irradiated to doses of up to 10 Gy with both 4 MV photon and 26.5 MeV proton beams, while pieces of the HDV2 radiochromic films were irradiated to doses of up to 128 Gy proton beam. Irradiated pieces of the EBT3 films were tested for activation using Germanium detector. Their energy spectra were measured over a period of 40 minutes. EBT3 film model response was 3 times higher for protons than photons. When irradiated in proton beam the EBT3 was 24 times more sensitive than HDV2 films. For the EBT3 film model, few proton-activated processes were identified resulting in short-lived radioisotopes. EBT3 film can be used for measurements for doses of up to 10 Gy using a green color channel of the scanned images, while the red color channel of the HDV2 scanned film images can be used for measurements of much higher doses.

WE4PB02	An All-Purpose Accelerator Code, Zgoubi	simulation, damping, polarization, synchrotron	426
	F. Méot BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The ray-tracing code Zgoubi* has long been 6D-tracking through all possible types of fixed field rings*, including, recently, 6D transmission from injection-up to extraction-down in high power cyclotrons in the frame of ADS-Reactor R/D. This is to be added to the long exploited many other capabilities of the code as spin transport, in-flight decay, synchrotron radiation energy loss, etc. An overview will be given, including recent space-charge developments, with illustration including recent high power cyclotron applications. http://sourceforge.net/projects/zgoubi/, http://www.osti.gov/bridge/basicsearch.jsp **6-D beam dynamics simulations in FFAGs, F. Meot, ICFA Beam Dyn. Newslett.43:44-50 (2007)
	Slides WE4PB02 [4.414 MB]

TH1PB04	Fabrication of Hydrophobic Surfaces from Hydrophilic BeO by Alpha-Irradiation-Induced Nuclear Transmutation	controls, plasma, cyclotron, target	443
	E.J. Lee, M.G. Hur, J.H. Park KAERI, Daejon, Republic of Korea Y.B. Kong, Y.D. Park, J.M. Son, S.D. Yang Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongup-si, Jeollabuk-do, Republic of Korea
	Hydrophobic surfaces were simply fabricated by irradiating hydrophilic BeO surfaces with an alpha particle beam from a cyclotron. In this research, BeO disks were irradiated under conditions of ~25 MeV in alpha particle energy and ~1 μA in beam current with different irradiation time. After the alpha irradiation, the changes in the morphology and chemical composition of BeO surfaces were analyzed using a field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The wetting property of alpha-irradiated BeO surfaces is analyzed by measuring water contact angles (CAs). C and F atoms were created, and consequently, hydrophobic CFx functional groups were formed by the alpha irradiation of hydrophilic BeO. The amount of CFx functional groups on the surface increases as the irradiation time increases. In addition, the surface roughening, which also affects the surface wettability, was induced by the alpha irradiation. Accordingly, the CA of alpha-irradiated BeO surfaces gradually increases as the irradiation time increases. In conclusion, hydrophilic BeO surfaces could be easily converted to hydrophobic surfaces by the alpha irradiation.
	Slides TH1PB04 [5.545 MB]

TH2PB04	A Multi-Leaf Faraday Cup Especially for Proton Therapy of Ocular Tumors	proton, cyclotron, simulation, ion	458
	C.S.G. Kunert, J. Bundesmann, T. Damerow, A. Denker HZB, Berlin, Germany A. Weber Charite, Berlin, Germany
	The Helmholtz-Zentrum Berlin (HZB) provides together with the University Hospital Charité in Berlin a treatment of eye tumors with a proton beam. The 68 MeV proton beam is delivered by an isochronous cyclotron as main accelerator. In tumor irradiation treatment the positioning of the radiation field is very important. In eye tumor treatment it is even more important, due to the small and sensitive structures in the eye. Hence, due to the well defined Bragg peak, a proton beam is a good choice to achieve rather small fields of dose delivery. Again, due to the small structures in the eye, one needs to know the proton beam energy and the proton beam range with a high accuracy. One possible solution for a quick and high precision measurement of the range of such proton beams is a Multi-Leaf Faraday Cup (MLFC). This work has the task to develop such a MLFC concerning the special requirements of the eye tumor therapy. In this presentation an overview of the progress of this work will be given, regarding the MLFC principles and issues such as the first technical realization.
	Slides TH2PB04 [5.358 MB]

FR1PB02	Secondary Particle Dose and RBE Measurements Using High-Energy Proton Beams	proton, factory, background, ion	464
	M. Ghergherehchi, J.-S. Chai SKKU, Suwon, Republic of Korea D.H. Shin NCC, Goyang, Kyeonggi, Republic of Korea
	High- and intermediate-energy protons are not able to directly form a track in a CR-39 etch detector (TED). Such detectors, however, can be used for the detection and dosimetry of the beams of these particles through the registration of secondary charged particles with sufficiently high values of linear energy transfer (LET). The studied were realized in a clinical proton beam of the NCC Korea, with primary energy of 72 to 220 MeV (1.1 to 0.4 KeV/ μm). The contribution of the secondary particle dose and the value of RBE both increase with decreasing proton energy. A strong agreement between experimentally obtained results and the predicted total cross sections was verified by the Alice code. Stimulation of the secondary particle dose by the Geant4 code also predicted results in agreement by experimental results. It is clear that higher cross sectional values lead to an increased production of secondary particles. This secondary particle dose is highly important for applications such as radiotherapy, radiobiology, and radiation protection.
	Slides FR1PB02 [2.955 MB]

Paper

Title

Other Keywords

Page

MOPPT001

Status Report of the Cyclotrons C-30, CS-30 and RDS-111 at KFSHRC, Saudi Arabia

cyclotron, target, proton, controls

28

F.M. Alrumayan, M.S. Shawoo, M. Vora
King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Kingdom of Saudi Arabia

Experience gained since the commissioning of the IBA C-30 Cyclotron at the King Faisal Specialist Hospital and Research Centre (KFSHRC) in 2010, has shown this facility to be viable entity. In addition to the C-30 Cyclotron, the facility includes two other Cyclotrons namely; the RDS-111 and the CS30 Cyclotrons. The latter has dual responsibilities; while is kept as a backup for the other Cyclotrons for radioisotopes production, it’s used for proton therapy researches and Bragg Peak measurements at that particular energy. During the commission of the C30 cyclotron, 700 uA dual beam were measured. Facility operating history, usage and radiopharmaceuticals productions are described.

MOPPT008

Present Status of Cyclotrons (NIRS-930, HM-18) at NIRS

cyclotron, proton, injection, ion

46

S. Hojo, T. Honma, K. Katagiri, M. Nakao, A. Noda, K. Noda, A. Sugiura
NIRS, Chiba-shi, Japan
A.K. Komiyama, T. Okada, Y. Takahashi
AEC, Chiba, Japan

The cyclotron facility at National Institute of Radiological Science (NIRS) consists of a NIRS-930 cyclotron (Thomson-CSF AVF-930, Kb=110 MeV and Kf=90 MeV) and a small cyclotron HM-18(Sumitomo- Heavy- Industry HM-18). The NIRS-930 has been used for production of short-lived radio-pharmaceuticals for PET, research of physics, developments of particle detectors in space, and so on. The orbit of a beam in the NIRS-930 cyclotron was simulated with integrated approach to modelling of the cyclotron, including calculation of electromagnetic fields of the structural elements. And some improvements such as installation of extracted beam probe, a beam attenuator and a beam viewer in an injection beam line, were performed in the NIRS-930. The HM-18 has been used for production of short-lived radio-pharmaceuticals for PET. It allows us to accelerate H-and D- ion at fixed energies of 18 and 9 MeV, respectively. In order to improve the isochronism, a phase probe has been newly installed in the HM-18. Above improvements and operational status of the cyclotron facility are to be presented in this report.

MOPPT030

Past, Present and Future Activities for Radiation Effects Testing at JULIC/COSY

proton, simulation, neutron, ion

88

S.K. Hoeffgen, S. Metzger
FhG, Euskirchen, Germany
R. Brings, O. Felden, R. Gebel, R. Maier, D. Prasuhn
FZJ, Jülich, Germany
M. Brugger, R. Garcia Alia
CERN, Geneva, Switzerland

The testing of radiation effects (displacement damage DD, single event effects SEE) with energetic protons for electronics used in space and accelerators is of growing importance. Setup and past experience of a dedicated test stand used by Fraunhofer INT at the JULIC cyclotron will be presented. For general DD testing and for testing SEE of the trapped protons in space, the energy of 35 MeV of the JULIC Cyclotron is usually sufficient. During solar proton events, as well as at high energy accelerators (CERN, FAIR), electronics are confronted with protons of much higher energy. Recent scientific studies have shown that for single event upsets* as well as destructive failures (e.g, single event latch-ups)** a cross section measured at energies in the tens oF one/two-hundred MeV range (e.g. PIF@PSI) can significantly underestimate the failure rate. To avoid unnecessary high safety margins there is a growing need for the opportunity to test electronics at several GeV, like the beam provided by the Cooler-Synchrotron COSY in Jülich.
*R. Garcia Alia et. al., accepted for publication, IEEE TNS (2013), DOI:10.1109/TNS.2013.2249096
**J. R. Schwank et al., IEEE TNS, vol. 52, pp2622 (2005)

TUPSH005

Investigation of Cyclotron Carbon Foil Lifetime in Relation to its Thickness

electron, proton, ion, cyclotron

227

J.-W. Kim, S. Hong, J.H. Kim
IBS, Daejeon, Republic of Korea
Y. Choi
Dongguk University, Gyeongju, Republic of Korea
Y.-S. Kim
Energy & Environmental System, Gyeongju, Republic of Korea

For extracting positive hydrogen atoms from accelerated negative ones, a thin carbon foil is usually used to stripe two electrons from negative atoms, which consists of one proton and two electrons traveling together up to 70MeV proton. The kinetic energy of electron is 38.13keV at the moment of stripping. The energy loss of protons and electrons in carbon foil could be estimated by the multiplication of stopping power (dE/dz) and the foil thickness where passing through. The stopping powers were estimated with 8.5 and 7.25 MeV/(g/cm²) for the proton and electron, respectively. In cyclotron the stripper is located in a strong magnetic field of ~Tesla, which makes electrons circular motion around the foil depositing all their kinetic energies into it. In this study, three different carbon foil thicknesses (200, 400, and 800 ug/cm²) were employed to investigate the correlation of foil temperature and their lifetime for the case of 1mA proton extraction. We are aiming the lifetime of a stripper foil to be as long as 2 weeks for irradiating protons onto an ISOL target. An effective lifetime of foils will be discussed as a function of a foil peak temperature.

TUPSH014

An Integrated Self-Supporting Mini-Beamline for PET Cyclotrons

cyclotron, target, focusing, controls

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.

TUPSH016

Trim Coil Unbalance of the 88-Inch Cyclotron

cyclotron, ion, power-supply, injection

254

M. Kireeff Covo, B. Bingham, C.M. Lyneis, B. Ninemire, L. Phair, P. Pipersky, A. Ratti, M.M. Strohmeier, D.S. Todd
LBNL, Berkeley, California, USA
K.Y. Franzen
Mevion, Littleton, Massachusetts, USA

Funding: Work supported by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Nuclear Physics Division of the U.S. Department of Energy under Contract DE-AC02-05CH11231.
The 88-inch cyclotron Dee probe shows large losses inside the radius of 20 cm and suggests problems in the ion beam injection. The current of the top and bottom innermost trim coil 1 is unbalanced to study effects of the axial injection displacement. A new beam profile monitor images the ion beam bunches, turn by turn, and the beam center of mass position is measured. The technique allows increasing the beam transmission through the cyclotron.

WEPSH007

Radiochromic Film as a Dosimetric Tool for Low Energy Proton Beams

proton, photon, cyclotron, ion

397

S. Devic, S. Aldelaijan, F.M. Alrumayan, F. Alzorkani, B.M. Moftah, M. Shehadeh
King Faisal Specialist Hospital and Research Centre, Riyadh 11211, Kingdom of Saudi Arabia

Funding: King Abdulaziz City for Science and Technology (KACST), Grant No 11-BIO1428-20
EBT3 and HDV2 GAFCHROMICTM films were tested for dose measurements at a 26.5 MeV and 6 mm Bragg peak proton beam. Beam output was calibrated using IAEA TRS-398 reference dosimetry protocol with calibrated chamber in water. Films were calibrated in terms of dose to water by exposing calibration film pieces within a solid water phantom at depth of 3 mm. EBT3 films were irradiated to doses of up to 10 Gy with both 4 MV photon and 26.5 MeV proton beams, while pieces of the HDV2 radiochromic films were irradiated to doses of up to 128 Gy proton beam. Irradiated pieces of the EBT3 films were tested for activation using Germanium detector. Their energy spectra were measured over a period of 40 minutes. EBT3 film model response was 3 times higher for protons than photons. When irradiated in proton beam the EBT3 was 24 times more sensitive than HDV2 films. For the EBT3 film model, few proton-activated processes were identified resulting in short-lived radioisotopes. EBT3 film can be used for measurements for doses of up to 10 Gy using a green color channel of the scanned images, while the red color channel of the HDV2 scanned film images can be used for measurements of much higher doses.

WE4PB02

An All-Purpose Accelerator Code, Zgoubi

simulation, damping, polarization, synchrotron

426

F. Méot
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The ray-tracing code Zgoubi* has long been 6D-tracking through all possible types of fixed field rings**, including, recently, 6D transmission from injection-up to extraction-down in high power cyclotrons in the frame of ADS-Reactor R/D. This is to be added to the long exploited many other capabilities of the code as spin transport, in-flight decay, synchrotron radiation energy loss, etc. An overview will be given, including recent space-charge developments, with illustration including recent high power cyclotron applications.
*http://sourceforge.net/projects/zgoubi/, http://www.osti.gov/bridge/basicsearch.jsp
**6-D beam dynamics simulations in FFAGs, F. Meot, ICFA Beam Dyn. Newslett.43:44-50 (2007)

Slides WE4PB02 [4.414 MB]

TH1PB04

Fabrication of Hydrophobic Surfaces from Hydrophilic BeO by Alpha-Irradiation-Induced Nuclear Transmutation

controls, plasma, cyclotron, target

443

E.J. Lee, M.G. Hur, J.H. Park
KAERI, Daejon, Republic of Korea
Y.B. Kong, Y.D. Park, J.M. Son, S.D. Yang
Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongup-si, Jeollabuk-do, Republic of Korea

Hydrophobic surfaces were simply fabricated by irradiating hydrophilic BeO surfaces with an alpha particle beam from a cyclotron. In this research, BeO disks were irradiated under conditions of ~25 MeV in alpha particle energy and ~1 μA in beam current with different irradiation time. After the alpha irradiation, the changes in the morphology and chemical composition of BeO surfaces were analyzed using a field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The wetting property of alpha-irradiated BeO surfaces is analyzed by measuring water contact angles (CAs). C and F atoms were created, and consequently, hydrophobic CFx functional groups were formed by the alpha irradiation of hydrophilic BeO. The amount of CFx functional groups on the surface increases as the irradiation time increases. In addition, the surface roughening, which also affects the surface wettability, was induced by the alpha irradiation. Accordingly, the CA of alpha-irradiated BeO surfaces gradually increases as the irradiation time increases. In conclusion, hydrophilic BeO surfaces could be easily converted to hydrophobic surfaces by the alpha irradiation.

Slides TH1PB04 [5.545 MB]

TH2PB04

A Multi-Leaf Faraday Cup Especially for Proton Therapy of Ocular Tumors

proton, cyclotron, simulation, ion

458

C.S.G. Kunert, J. Bundesmann, T. Damerow, A. Denker
HZB, Berlin, Germany
A. Weber
Charite, Berlin, Germany

The Helmholtz-Zentrum Berlin (HZB) provides together with the University Hospital Charité in Berlin a treatment of eye tumors with a proton beam. The 68 MeV proton beam is delivered by an isochronous cyclotron as main accelerator. In tumor irradiation treatment the positioning of the radiation field is very important. In eye tumor treatment it is even more important, due to the small and sensitive structures in the eye. Hence, due to the well defined Bragg peak, a proton beam is a good choice to achieve rather small fields of dose delivery. Again, due to the small structures in the eye, one needs to know the proton beam energy and the proton beam range with a high accuracy. One possible solution for a quick and high precision measurement of the range of such proton beams is a Multi-Leaf Faraday Cup (MLFC). This work has the task to develop such a MLFC concerning the special requirements of the eye tumor therapy. In this presentation an overview of the progress of this work will be given, regarding the MLFC principles and issues such as the first technical realization.

Slides TH2PB04 [5.358 MB]

FR1PB02

Secondary Particle Dose and RBE Measurements Using High-Energy Proton Beams

proton, factory, background, ion

464

M. Ghergherehchi, J.-S. Chai
SKKU, Suwon, Republic of Korea
D.H. Shin
NCC, Goyang, Kyeonggi, Republic of Korea

High- and intermediate-energy protons are not able to directly form a track in a CR-39 etch detector (TED). Such detectors, however, can be used for the detection and dosimetry of the beams of these particles through the registration of secondary charged particles with sufficiently high values of linear energy transfer (LET). The studied were realized in a clinical proton beam of the NCC Korea, with primary energy of 72 to 220 MeV (1.1 to 0.4 KeV/ μm). The contribution of the secondary particle dose and the value of RBE both increase with decreasing proton energy. A strong agreement between experimentally obtained results and the predicted total cross sections was verified by the Alice code. Stimulation of the secondary particle dose by the Geant4 code also predicted results in agreement by experimental results. It is clear that higher cross sectional values lead to an increased production of secondary particles. This secondary particle dose is highly important for applications such as radiotherapy, radiobiology, and radiation protection.

Slides FR1PB02 [2.955 MB]