TUPOT —  Poster Session 2   (24-Aug-10   16:10—18:00)

Paper	Title	Page
TUPOT001	Plans for Laser Ablation of Actinides into an ECRIS for Accelerator Mass Spectroscopy	110
	R.C. Pardo, F.G. Kondev, S.A. Kondrashev, C. Nair, T. Palchan, E. Rehm, R.H. Scott, R.C. Vondrasek ANL, Argonne, USA P. Collon University of Notre Dame, Notre Dame, USA G. Imel ISU, Pocatello, Idaho, USA C. McGrath, G. Palmotti, M. Salvatores, G. Youinou Idaho National Laboratory, Idaho, USA M. Paul The Hebrew University of Jerusalem, The Racah Institute of Physics, Jerusalem, Israel
	Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357. A project using accelerator mass spectrometry (AMS) at the ATLAS facility to measure neutron capture rates on a wide range of actinides in a reactor environment is underway. This project will require the measurement of many samples with high precision and accuracy. The AMS technique at ATLAS is based on production of highly-charged positive ions in an ECRIS followed by linear acceleration. We have chosen to use laser ablation as the best means of feeding the actinide material into the ion source because we believe this technique will have more efficiency and lower chamber contamination thus reducing ‘cross talk’ between samples. In addition a multi-sample holder/changer is part of the project to allow quick change between multiple samples. The status of the project, design, and goals for initial off-line ablation tests will be discussed as well as the overall project schedule.
	Poster TUPOT001 [0.152 MB]
TUPOT002	Enhancement of ECR Performances by Means of Carbon Nanotubes Based Electron Guns	114
	F. Odorici, M. Cuffiani, L. Malferrari, R. Rizzoli, G.P. Veronese INFN-Bologna, Bologna, Italy G. Castro, L. Celona, G. Ciavola, N. Gambino, S. Gammino, D. Mascali, R. Miracoli, F.P. Romano INFN/LNS, Catania, Italy T. Serafino Università di Messina, Messina, Italy
	One of the main goals of the scientific community which deals with ECR Ion Sources is the optimization of the Eelectron Energy Distribution Function (EEDF) inside the plasma. The EEDF consists of three different populations (cold, warm and hot electrons): the cold and the warm populations are responsible of the stabilization and of the efficient ionization of the plasma respectively. The presence of the hot population is doubly detrimental: in high frequency sources they lead to the heating of LHe in the superconducting coils’ cryostat and are also useless for the generation of high intensity ion beams, because of their small cross section. Therefore the injection of additional electrons inside the plasma may increase the density of cold and warm electrons, enabling at the same time to reduce the number of the high energy ones. The CANTES experiment tested the use of carbon nanotubes (CNTs) to emit electrons in presence of strong applied electric fields, in order to provide additional electrons to the plasma core. This technique was used with the Caesar ECR ion source, at INFN-LNS, demonstrating that the total extracted ion current is increased and that a relevant reduction of the number of “high energy” electrons (above 100 keV) can be obtained. This last result is even more important, because CNTs may be an effective and reliable tool to permit the operation of ECRIS at large power and high frequencies without any detrimental effect on the source stability and reliability coming from hot electrons. Details of the construction of CNTs based electron gun and their behaviour in plasma environments are presented. Preliminary results in terms of performances of the Caesar ECR ion source and possible future applications will be also discussed.
	Poster TUPOT002 [1.914 MB]
TUPOT003	A New BETSI Test Bench at CEA/Saclay	117
	S. Nyckees, Y. Gauthier, C.M. Mateo CEA/IRFU, Gif-sur-Yvette, France G. Adroit, O. Delferrière, R.D. Duperrier, R. Gobin, F. Harrault, O. Napoly, B. Pottin, Y. Sauce, F. Senée, O. Tuske, T.V. Vacher CEA/DSM/IRFU, France
	By the 90s, CEA has undertaken to develop the production of high intensity light ion beams from plasma generated by electron cyclotron resonance (ECR). Important results were obtained with the SILHI source in pulsed or continuous mode. Presently, CEA/Saclay is now involved in the construction of different injectors dedicated to large infrastructures like IFMIF or Spiral 2. Other installations are also interested by high intensity ion sources like ESS or FAIR. To improve and test new sources, a new test bench named BETSI (Banc d'Etudes et de Tests des Sources d'Ions) is now operating for several months. Low energy beam line diagnostics consist of a Faraday cup, cameras and a species analyzer. The SILHI emittance scanner can also be installed on the beam line. On this test bench, different permanent magnet source configurations are tested. In order to modify plasma chamber size and shape, a new ECR source design is developed. An experimental study of the plasma visible light emitted through electrodes was implemented on BETSI using a monochromator. Extracted beam intensity of a permanent magnet source is compared to plasma light emission. Results obtained with monochromator will be compared with SOLMAXP code in order to explore radio frequency wave and plasma interaction.
	Poster TUPOT003 [4.044 MB]
TUPOT004	Microgan ECR Ion Source in a Van de Graaff Accelerator Terminal	120
	G. Gaubert, C. Bieth, W. Bougy, B.N. Brionne, X. Donzel, A. Sineau, O. Tasset, C. Vallerand, A.C.C. Villari PANTECHNIK, BAYEUX, France C. Chavez-de-Jesus, T. Gamboni, W. Geerts, G. Giorginis, R. Jaime Tornin, G. Lövestam, W. Mondelaers JRC/IRMM, Geel, Belgium
	The Van de Graaff accelerator at IRMM works since many years providing proton, deuteron and helium beams for nuclear data measurements. The original ion source was of RF type with quartz bottle. This kind of source, as well known, needs regular maintenance for which the accelerator tank must be completely opened. The heavy usage at high currents of the IRMM accelerator necessitated an opening about once every month. Recently, the full permanent magnet Microgan ECR ion source from PANTECHNIK was installed into a new terminal platform together with a solid state amplifier of 50W, a dedicated dosing system for 4 gases (with respective gas bottles H2, D2, He and Ar), and a set of dedicated power supplies and electronic devices for the remote tuning of the source. The new system shows a very stable behavior of the produced beam allowing running the Van de Graff without maintenance for several months. This contribution will describe the full installed system in details (working at high pressure in the terminal, spark effects and optic of the extraction).
	Poster TUPOT004 [1.715 MB]
TUPOT005	An ECR Table Plasma Generator	124
	R. Rácz, S. Biri ATOMKI, Debrecen, Hungary J. Pálinkás DU, Debrecen, Hungary
	A simple ECR plasma device was built in our lab using the “spare parts” of the ATOMKI ECR ion source. We call it “ECR table plasma generator”. It consists of a relatively big plasma chamber (ID=10 cm, L=40 cm) in a thin NdFeB hexapole magnet with independent vacuum and gas dosing systems. For microwave coupling two low power TWTAs can be applied individually or simultaneously, operating in the 6-18 GHz range. There is no axial magnetic field and there is no extraction. The intended fields of usage of the plasma generator are: A simple, cheap and safe educational working place for students. To prepare, to test or to simulate measurements with electrostatic movable Langmuir probes. The exchange time of the (damaged) probes is very short. To prepare, to test or to simulate plasma diagnostic measurements in the visible light and X-ray ranges using cameras and spectrometers. To cover and/or to modify solid surfaces with plasma particles, including fullerenes. In the paper the technical details of the plasma generator and some preliminary plasma photo results are shown.
	Poster TUPOT005 [0.871 MB]
TUPOT006	Using Mass-Flow Controllers for Obtaining Extremely Stable ECR Ion Source Beams	127
	X. Donzel, W. Bougy, B.N. Brionne, G. Gaubert, A. Sineau, O. Tasset, C. Vallerand, A.C.C. Villari PANTECHNIK, BAYEUX, France R. Leroy GANIL, Caen, France
	Beam stability and reproducibility is of paramount importance in applications requiring precise control of implanted radiation dose, like in the case of Hadrontherapy. The beam intensity over several weeks or months should be kept constant. Moreover, the timing for changing the nature of the beam and, as a consequence, the tuning of the source should be minimized. Standard valves usually used in conjunction of ECR ion sources have the disadvantage of controlling the conductance, which can vary significantly with external conditions, like ambient temperature and inlet pressure of the gas. The use of flow controllers is the natural way for avoiding these external constraints. In this contribution we present the results obtained using a new model of Mass-flow controller in the source Supernanogan, for production of C4+ and H3+ beams. Extremely stable beams (± 2.5%) without retuning of the source over several weeks could be obtained. The reproducibility of the source tuning parameters could also be demonstrated.
	Poster TUPOT006 [4.386 MB]
TUPOT007	Preliminary Design of BLISI, an Off Resonance Microwave Proton Source	130
	S. Djekic, I. Bustinduy, D. Cortazar, D. Fernandez-Cañoto, H. Hassanzadegan, J.L. Munoz, D. de Cos ESS Bilbao, Bilbao, Spain F.J. Bermejo Bilbao, Faculty of Science and Technology, Bilbao, Spain M.A. Carrera, J.H. Galipienzo AVS, Eibar, Gipuzkoa, Spain V. Etxebarria, J. Jugo, J. Portilla University of the Basque Country, Faculty of Science and Technology, Bilbao, Spain J. Feuchtwanger, I. Rueda ESS-Bilbao, Zamudio, Spain J. Lucas Elytt Energy, Madrid, Spain
	A new high current off resonance microwave H+ source is currently in the last stages of design at ESS-Bilbao, in collaboration with two external companies Elytt and AVS. The design is intended to be a high-stability, high-current ion source capable of delivering a 70 mA proton beam with a 70 keV energy at the end of the extraction. The plasma system designed by Elytt consists of a water-cooled plasma chamber that sits between two independently powered magnetic coils that generate the ECR magnetic field; in addition they can be moved independently to further shape the magnetic field in the chamber. A CPI 2.7 GHz klystron provides the microwave energy and a fully controlled microwave system to minimize reflected power and improve the source overall performance is also under construction. The extraction column designed by AVS will consist of a movable tetrode system designed for a maximum acceleration potential of 70 kV, the shape of the electrodes is at an earlier design stage at ESS-Bilbao. We will present the current layout of the source, simulations and schematics of the source.
	Poster TUPOT007 [3.954 MB]
TUPOT008	Performance of the LBNL AECR-U with a TWTA	133
	J.Y. Benitez, D. Leitner, C.M. Lyneis LBNL, Berkeley, California, USA M.K. Covo LLNL, Livermore, California, USA
	The Advanced Electron Cyclotron Resonance - Upgrade ion source (AECR-U) at the Lawrence Berkeley National Laboratory has successfully utilized double frequency microwave heating (14.3 GHz and 10.4 GHz) for several years [1]. Recently a traveling wave tube amplifier (TWTA), providing frequencies in the range of 10.75GHz-12.75GHz, was added as a secondary heating frequency, replacing the previous 10.4 GHz Klystron. The TWTA opens the possibility to explore a wide range of secondary frequencies and a study has been conducted to understand and optimize its coupling into the AECR-U. In particular, the reflected power dependence on heating frequency has been mapped out with and without the presence of plasma. A comparison is made to determine how the presence of plasma, confinement fields, and other source parameters affect the reflected power and if and how the amount of reflected power can be correlated to the source ion beam performance. [1] Z. Q. Xie and C. M. Lyneis, Rev. Sci. Instrum. 66 (1995).
	Poster TUPOT008 [0.213 MB]
TUPOT009	Measurements of Bremsstrahlung Radiation and X-Ray Heat Load to Cryostat on SECRAL	134
	H. Zhao, Y. Cao, X.X. Li, D. Xie, W.H. Zhang, X.Z. Zhang, H.W. Zhao, Y.H. Zhu IMP, Lanzhou, People's Republic of China W. Lu Graduate School of the Chinese Academy of Sciences, Beijing, People's Republic of China
	Measurement of Bremsstrahlung radiation from ECR plasma can yield certain information of the ECR heating process and a plausible estimate of the X-ray heat load to the cryostat of a superconducting ECR source which needs seriously addressed. With a newly-developed collimation system, which defines a narrower spatial range of the measurement and provides an effective shielding from the background, a systematic measurement of the Bremmstrahlung emitted axially from the SECRAL (Superconducting ECR Ion Source with Advanced design in Lanzhou) plasma were carried out recently. The spectral temperature Tspe, a relative index of mean energy of the plasma hot electrons, was derived through linear fitting of the spectra in semi-logarithm coordinates. This article will present and discuss the evolutions of the X-ray flux and the hot electron energy with various source parameters, such as heating frequency, RF power and magnetic field configuration. And possible solutions to reduce the X-ray heat load induced by Bremsstrahlung radiation are proposed and discussed.
	Poster TUPOT009 [1.581 MB]
TUPOT010	Effects of Microwave Frequency Fine Tuning on the Performance of JYFL 14 GHz ECRIS	137
	V.A. Toivanen, V.P. Aho, J. Ärje, P. Jones, J.A. Kauppinen, H. A. Koivisto, P. Peura, O.A. Tarvainen JYFL, Jyväskylä, Finland L. Celona, G. Ciavola, S. Gammino INFN/LNS, Catania, Italy A. Galatà INFN/LNL, Legnaro (PD), Italy D. Mascali CSFNSM, Catania, Italy T. Ropponen NSCL, East Lansing, Michigan, USA
	Measurements have been carried out at Department of Physics, University of Jyväskylä (JYFL) to study the effects of microwave frequency fine tuning on the performance of JYFL 14 GHz electron cyclotron resonance ion source. The frequency was varied within an 85 MHz band around the normal operation frequency of 14.085 GHz. The radial bremsstrahlung emission was measured for plasma diagnostics purposes and mass separated ion beam currents extracted from the ion source were recorded at the same time. Also, beam quality studies were conducted by measuring the ion beam emittance and shape with and without enhanced space charge compensation. The obtained results are presented and possible origins of seen phenomena in measured quantities are discussed.
	Poster TUPOT010 [0.678 MB]
TUPOT011	Measurement of the Diamagnetic Current on the LBNL 6.4 GHz ECR Ion Source	140
	J.D. Noland, J.Y. Benitez, M. Kireeff Covo, D. Leitner, C.M. Lyneis LBNL, Berkeley, California, USA O.A. Tarvainen JYFL, Jyväskylä, Finland J. Verboncoeur UCB, Berkeley, California, USA
	Two standard plasma diagnostics (x-ray spectroscopy and measurement of the diamagnetic current) have been employed at the LBNL 6.4 GHz ECR. These diagnostics are combined with time resolved current measurements to study the plasma breakdown, build up and decay times, as well as electron heating. Individual charged particles in a magnetized plasma orbit in such a way that the magnetic field produced by their motion opposes any externally applied magnetic field. When a charged particle density gradient exists in a plasma, a net current arises. This “diamagnetic” current is proportional to the time-rate-of-change of the perpendicular component of the plasma pressure, and can be measured with a loop of wire as the plasma ignites or decays. Another common plasma diagnostic that is used to characterize an ECR plasma is measurement of the x-ray spectra created when energetic electrons scatter off of plasma ions. The x-ray spectra provide insight on the relative abundance of electrons of different energies, and thus the electron energy distribution function. The x-ray spectra can also be used to estimate the total x-ray power produced by the plasma. In this paper diamagnetic loop diagnostics and set-up is described in detail. In addition, diamagnetic loop and low energy x-ray measurements (few keV to 100 keV) taken on the LBNL 6.4 GHz ECR ion source are presented and discussed.
	Poster TUPOT011 [1.522 MB]
TUPOT012	Microwave Frequency Dependence of the Properties of the Ion Beam Extracted From a Caprice Type ECRIS	143
	F. Maimone, R. Lang, J. Mäder, J. Roßbach, P. Spädtke, K. Tinschert GSI, Darmstadt, Germany L. Celona INFN/LNS, Catania, Italy F. Maimone DMFCI, Catania, Italy
	In order to improve the quality of ion beams extracted from ECR ion sources it is mandatory to better understand the relations between the plasma conditions and the beam properties. The present investigations concentrate on the analysis of different beam properties under the influence of various applications of frequency tuning and of multiple frequency heating. The microwave frequency feeding the plasma affects the electromagnetic field distribution and the dimension and position of the ECR surface inside the plasma chamber. This in turn has an influence on the generation of the extracted ion beam in terms of its intensity, of its shape and of its emittance. In order to analyze the corresponding effects measurements have been performed with the Caprice type ECRIS installed at the ECR Injector Setup (EIS) of GSI. The experimental setup uses a new arrangement of one or more microwave sweep generators which feed a Traveling Wave Tube amplifier covering a wide frequency range from 12.5 to 18 GHz. This arrangement provides a precise determination of the frequencies and of the reflection coefficient along with the beam properties. A sequence of viewing targets positioned inside the beam line monitors the beam shape.
	Poster TUPOT012 [1.245 MB]
TUPOT013	Influence of Initial Plasma Density and Mean Electron Energy on the Preglow Effect	146
	I. Izotov, V. Sidorov, V. Skalyga, V. Zorin IAP/RAS, Nizhny Novgorod, Russia H. A. Koivisto, O.A. Tarvainen, V.A. Toivanen JYFL, Jyväskylä, Finland
	The investigation of the Preglow effect is driven with the aim of creating a short-pulsed multicharged ion source. Recent experimental investigations have revealed strong influence of seed electrons, i.e. initial plasma density, on the amplitude and duration of the Preglow peak [1]. Present work, consisting of experiments and simulations, is dedicated to further investigation of the Preglow dependence on initial plasma density and electrons energy. Experimental investigation was performed at University of Jyväskylä (JYFL) with the A-ECR type ECRIS operated with 14 GHz frequency. Helium was used for the study. An initial ionization degree of the gas was varied by changing the pulse duration and duty factor. Time-resolved ion currents of He+ and He2+ were recorded. Calculations were made by using 0-dimensional model described in references [2], [3] and based on the balance equations for the particles confined in the magnetic trap. Results of simulation are compared with experimental Preglow peaks and discussed. Good agreement between experimental data and simulation encourages us to conduct a further study, aimed at optimizing the Preglow by tuning source parameters and initial plasma conditions. [1] O. Tarvainen et al, Rev. Sci. Instrum., 81, 02A303, 2010. [2] T. Thuillier et al, Rev. Sci. Instrum., 79, 02A314, 2008. [3] I. Izotov et all. IEEE Trans. Plasma Sci. 36, 1494, 2008.
	Poster TUPOT013 [0.569 MB]
TUPOT014	Optimized Extraction Conditions From High Power ECRIS by Dedicated Dielectric Structures	147
	L. Schächter, S. Dobrescu IFIN, Magurele- Bucuresti, Romania K.E. Stiebing IKF, Frankfurt-am-Main, Germany
	The MD-method of enhancing the ion output from ECR ion sources is well established and basically works via two mechanisms, the regenerative injection of cold electrons from an emissive dielectric layer on the plasma chamber walls and via the cutting of compensating wall currents, which results in an improved ion extraction from the plasma. As this extraction from the plasma becomes a more and more challenging issue for modern ECRIS installations with high microwave power input, a series of experiments was carried out at the 14 GHz ECRIS of the Institut für Kernphysik in Frankfurt/Main, Germany (IKF). In contrast to our earlier work, in these experiments emphasis was put on the second of the above mechanisms namely to influence the sheath potential at the extraction by structures with special dielectric properties. Two different types of dielectric structures, Tantalum-oxide and Aluminum oxide (the latter also being used for the MD-method) with contrastingly different electrical properties were mounted on the extraction electrode of the IKF-ECRIS, facing the plasma. For both structures an increase of the extracted ion beam currents for middle and high charge states by 60-80 % was observed. The method is able to be applied also to other ECR ion sources for increasing the extracted ion beam performances.
	Poster TUPOT014 [0.510 MB]
TUPOT015	Permanent Magnet ECRIS for the KEK Digital Accelerator	150
	K.W. Leo, T. Adachi Sokendai, Ibaraki, Japan T. Arai, K. Koyama, M. Wake KEK, Ibaraki, Japan K. Okazaki Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture, Japan K. Takayama TIT, Yokohama, Japan
	The existing KEK 500 MeV booster synchrotron is renovated into a digital accelerator (DA) capable of accelerating all species of ion [1]. The KEK-DA is an induction synchrotron employing no large injector. Its concept was demonstrated in 2006 using the 12 GeV proton synchrotron [2,3], where a proton bunch was accelerated with pulse voltages generated by a transformer instead of RF. In the KEK-DA, O, Ne, and Ar ions from the ECRIS embedded in the 200 kV high-voltage terminal (HVT) are directly injected into the ring though the low energy beam transport line. The permanent magnet ECRIS, in which a plasma is fired by x-band microwave pulses of 3 msec at 10 Hz, has been assembled at KEK. Its operational performance such as charge-state spectrum, emittance, and current is tested since the last year. In addition, the HVT with a voltage stabilizing circuit is being assembled now. Beam dynamical analysis from the cathode hall to the separation magnet, where possible charge-state ions are contaminated in the space-charge limit and beam focusing is realized through the Einzel lens and tandem acceleration gaps, is discussed as well as operational characteristics of the ECRIS. [1] K. Takayama et al., “All-ion Accelerator: an Injector-free Synchrotron”, J. of Appl. Phys. 101, 063304(2007). [2] K. Takayama et al., “Experimental Demonstration of the Induction Synchrotron”, Phys. Rev. Lett. 98, 054801 (2007). [3] K. Takayama and R.Briggs (Eds.), Induction Accelerators (Springer-Verlarg, 2010).
	Poster TUPOT015 [1.947 MB]
TUPOT016	Long-Term Operation Experience With Two ECR Ion Sources and Planned Extensions at HIT	153
	T. Winkelmann, R. Cee, Th. Haberer, B. Naas, A. Peters HIT, Heidelberg, Germany
	The HIT (Heidelberg Ion Beam Therapy Center) is the first hospital-based treatment facility at a hospital in Europe where patients can be treated with protons and carbon ions. Since the commissioning starting in 2006 two 14.5 GHz electron cyclotron resonance ion sources are routinely used to produce a variety of ion beams from protons up to oxygen. The operating time is 330 days per year, our experience after three years of continuous operation will be presented. In the future a helium beam for patient treatment is requested, therefore a third ion source will be integrated. This third ECR source with a newly designed extraction system and a spectrometer line will be installed at a testbench to commission and validate this section. Different test settings are foreseen to study helium operation as well as enhanced parameter sets for proton and carbon beams in combination with a modified beam transport line for higher transmission efficiency. An outlook to the possible integration scheme of the new ion source into the production facility will be discussed.
	Poster TUPOT016 [4.294 MB]
TUPOT017	CEA/Saclay Light Ion Sources Status and Developments	156
	R. Gobin, C.M. Mateo, S. Nyckees CEA/IRFU, Gif-sur-Yvette, France G. Adroit, G. Bourdelle, N. Chauvin, O. Delferrière, Y. Gauthier, P. Girardot, F. Harrault, C. Marolles, B. Pottin, Y. Sauce, F. Senée, O. Tuske, T.V. Vacher, C. Van Hille CEA/DSM/IRFU, France
	After several years of high intensity light ion beam production with the SILHI source, CEA Saclay is now involved in the construction of different injectors dedicated to large infrastructures like IFMIF or Spiral 2. Other installations are also interested by high intensity ion sources like ESS or FAIR. Such machines plan to produce and accelerate proton or deuteron beams in pulsed or continuous mode. The SILHI source, based on ECR plasma generation, already demonstrated its performance in both modes. As a consequence, at present time the construction of 2 new injectors for Spiral 2 and IFMIF (source and low energy beam lines) is in progress at CEA/Saclay. This article will report on the status of both installations. It will also point out on additional developments presently under progress for high intensity beam characterization or plasma production understanding. Such developments are mainly done with the new BETSI test bench operating for several months.
	Poster TUPOT017 [2.020 MB]
TUPOT018	Sheath Formation of a Plasma Containing Multiply Charged Ions, Cold and Hot Electrons, and Emitted Electrons	159
	H.J. You NFRI, Daejon, Republic of Korea
	A model of sheath formation was extended to a plasma containing multiply charged ions (MCIs), cold and hot electrons, and secondary electrons emitted either by MCIs or hot electrons. The present study was motivated by the fact that the secondary electron yields are strongly dependent on the charge state of the ions and on the incident energy of electrons. Therefore, the contributions of the secondary electron emissions on the sheath formation would be severe in ECRIS plasmas where the charge state of ions is high and highly energetic electrons exist. In the model, modification of the “Bohm criterion” was given; thereby the sheath potential drop and the critical emission condition were analyzed. The model calculations were made mainly on the effects of the emitted electrons on the variations of the sheath potential drop, the particle and heat flux to the wall, by which some explanations for the effect of secondary electrons in ECR ion sources are given.
	Poster TUPOT018 [0.259 MB]