Ultra-short ion and neutron pulse production

DOEpatents

Leung, Ka-Ngo; Barletta, William A.; Kwan, Joe W.

2006-01-10

An ion source has an extraction system configured to produce ultra-short ion pulses, i.e. pulses with pulse width of about 1 .mu.s or less, and a neutron source based on the ion source produces correspondingly ultra-short neutron pulses. To form a neutron source, a neutron generating target is positioned to receive an accelerated extracted ion beam from the ion source. To produce the ultra-short ion or neutron pulses, the apertures in the extraction system of the ion source are suitably sized to prevent ion leakage, the electrodes are suitably spaced, and the extraction voltage is controlled. The ion beam current leaving the source is regulated by applying ultra-short voltage pulses of a suitable voltage on the extraction electrode.

Design of a Prototype Positive Ion Source with Slit Aperture Type Extraction System

NASA Astrophysics Data System (ADS)

Sharma, Sanjeev K.; Vattilli, Prahlad; Choksi, Bhargav; Punyapu, Bharathi; Sidibomma, Rambabu; Bonagiri, Sridhar; Aggrawal, Deepak; Baruah, Ujjwal K.

2017-04-01

The neutral beam injector group at IPR aims at developing an experimental positive ion source capable of delivering H+ ion beam having energy of 30 - 40 keV and carrying an ion beam current of 5 A. The slit aperture based extraction system is chosen for extracting and accelerating the ions so as to achieve low divergence of the ion beam (< 0.5°). For producing H+ ions a magnetic multi-pole bucket type plasma chamber is selected. We calculated the magnetic field due to cusp magnets and trajectories (orbits) of the primary electrons to investigate the two magnetic configurations i.e. line cusp and checker board. Numerical simulation is also carried out by using OPERA-3D to study the characteristic performance of the slit aperture type extraction-acceleration system. We report here the results of the studies carried out on various aspects of the design of the slit aperture type positive ion source.

Development and characterization of a high-reliability, extended-lifetime H- ion source

NASA Astrophysics Data System (ADS)

Becerra, Gabriel; Barrows, Preston; Sherman, Joseph

2015-11-01

Phoenix Nuclear Labs (PNL) has designed and constructed a long-lifetime, negative hydrogen (H-) ion source, in partnership with Fermilab for an ion beam injector servicing future Intensity Frontier particle accelerators. The specifications for the low-energy beam transport (LEBT) section are 5-10 mA of continuous H- ion current at 30 keV with <0.2 π-mm-mrad emittance. Existing ion sources at Fermilab rely on plasma-facing electrodes, limiting their lifetime to a few hundred hours, while requiring relatively high gas loads on downstream components. PNL's design features an electron cyclotron resonance (ECR) microwave plasma driver which has been extensively developed in positive ion source systems, having demonstrated 1000+ hours of operation and >99% continuous uptime at PNL. Positive ions and hyperthermal neutrals drift toward a low-work-function surface, where a fraction is converted into H- hydrogen ions, which are subsequently extracted into a low-energy beam using electrostatic lenses. A magnetic filter preferentially removes high-energy electrons emitted by the source plasma, in order to mitigate H- ion destruction via electron-impact detachment. The design of the source subsystems and preliminary diagnostic results will be presented.

Alternating current corona discharge/atmospheric pressure chemical ionization for mass spectrometry.

PubMed

Habib, Ahsan; Usmanov, Dilshadbek; Ninomiya, Satoshi; Chen, Lee Chuin; Hiraoka, Kenzo

2013-12-30

Although alternating current (ac) corona discharge has been widely used in the fields of material science and technology, no reports have been published on its application to an atmospheric pressure chemical ionization (APCI) ion source. In this work, ac corona discharge for an APCI ion source has been examined for the first time. The ambient atmospheric pressure ac corona discharge (15 kHz, 2.6 kVptp ) was generated by using a stainless steel acupuncture needle. The generated ions were measured using an ion trap mass spectrometer. A comparative study on ac and direct current (dc) corona APCI ion sources was carried out using triacetone triperoxide and trinitrotoluene as test samples. The ac corona discharge gave ion signals as strong as dc corona discharge for both positive and negative ion modes. In addition, softer ionization was obtained with ac corona discharge than with dc corona discharge. The erosion of the needle tip induced by ac corona was less than that obtained with positive mode dc corona. A good 'yardstick' for assessing ac corona is that it can be used for both positive and negative ion modes without changing the polarity of the high-voltage power supply. Thus, ac corona can be an alternative to conventional dc corona for APCI ion sources. Copyright © 2013 John Wiley & Sons, Ltd.

Characterization of the ITER model negative ion source during long pulse operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemsworth, R.S.; Boilson, D.; Crowley, B.

2006-03-15

It is foreseen to operate the neutral beam system of the International Thermonuclear Experimental Reactor (ITER) for pulse lengths extending up to 1 h. The performance of the KAMABOKO III negative ion source, which is a model of the source designed for ITER, is being studied on the MANTIS test bed at Cadarache. This article reports the latest results from the characterization of the ion source, in particular electron energy distribution measurements and the comparison between positive ion and negative ion extraction from the source.

Non-volatile, solid state bistable electrical switch

NASA Technical Reports Server (NTRS)

Williams, Roger M. (Inventor)

1994-01-01

A bistable switching element is made of a material whose electrical resistance reversibly decreases in response to intercalation by positive ions. Flow of positive ions between the bistable switching element and a positive ion source is controlled by means of an electrical potential applied across a thermal switching element. The material of the thermal switching element generates heat in response to electrical current flow therethrough, which in turn causes the material to undergo a thermal phase transition from a high electrical resistance state to a low electrical resistance state as the temperature increases above a predetermined value. Application of the electrical potential in one direction renders the thermal switching element conductive to pass electron current out of the ion source. This causes positive ions to flow from the source into the bistable switching element and intercalate the same to produce a non-volatile, low resistance logic state. Application of the electrical potential in the opposite direction causes reverse current flow which de-intercalates the bistable logic switching element and produces a high resistance logic state.

Negative ion source with hollow cathode discharge plasma

DOEpatents

Hershcovitch, Ady; Prelec, Krsto

1983-01-01

A negative ion source of the type where negative ions are formed by bombarding a low-work-function surface with positive ions and neutral particles from a plasma, wherein a highly ionized plasma is injected into an anode space containing the low-work-function surface. The plasma is formed by hollow cathode discharge and injected into the anode space along the magnetic field lines. Preferably, the negative ion source is of the magnetron type.

Perspective on the Role of Negative Ions and Ion-Ion Plasmas in Heavy Ion Fusion Science, Magnetic Fusion Energy,and Related Fields

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grisham, L. R.; Kwan, J. W.

2008-08-01

Some years ago it was suggested that halogen negative ions could offer a feasible alternative path to positive ions as a heavy ion fusion driver beam which would not suffer degradation due to electron accumulation in the accelerator and beam transport system, and which could be converted to a neutral beam by photodetachment near the chamber entrance if desired. Since then, experiments have demonstrated that negative halogen beams can be extracted and accelerated away from the gas plume near the source with a surviving current density close to what could be achieved with a positive ion of similar mass, andmore » with comparable optical quality. In demonstrating the feasibility of halogen negative ions as heavy ion driver beams, ion - ion plasmas, an interesting and somewhat novel state of matter, were produced. These plasmas, produced near the extractor plane of the sources, appear, based upon many lines of experimental evidence, to consist of almost equal densities of positive and negative chlorine ions, with only a small component of free electrons. Serendipitously, the need to extract beams from this plasma for driver development provides a unique diagnostic tool to investigate the plasma, since each component - positive ions, negative ions, and electrons - can be extracted and measured separately. We discuss the relevance of these observations to understanding negative ion beam extraction from electronegative plasmas such as halogens, or the more familiar hydrogen of magnetic fusion ion sources. We suggest a concept which might improve negative hydrogen extraction by the addition of a halogen. The possibility and challenges of producing ion - ion plasmas with thin targets of halogens or, perhaps, salt, is briefly addressed.« less

Timeframe Dependent Fragment Ions Observed in In-Source Decay Experiments with β-Casein Using MALDI MS.

PubMed

Sekiya, Sadanori; Nagoshi, Keishiro; Iwamoto, Shinichi; Tanaka, Koichi; Takayama, Mitsuo

2015-09-01

The fragment ions observed with time-of-flight (TOF) and quadrupole ion trap (QIT) TOF mass spectrometers (MS) combined with matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) experiments of phosphorylated analytes β-casein and its model peptide were compared from the standpoint of the residence timeframe of analyte and fragment ions in the MALDI ion source and QIT cell. The QIT-TOF MS gave fragment c-, z'-, z-ANL, y-, and b-ions, and further degraded fragments originating from the loss of neutrals such as H(2)O, NH(3), CH(2)O (from serine), C2H4O (from threonine), and H(3)PO(4), whereas the TOF MS merely showed MALDI source-generated fragment c-, z'-, z-ANL, y-, and w-ions. The fragment ions observed in the QIT-TOF MS could be explained by the injection of the source-generated ions into the QIT cell or a cooperative effect of a little internal energy deposition, a long residence timeframe (140 ms) in the QIT cell, and specific amino acid effects on low-energy CID, whereas the source-generated fragments (c-, z'-, z-ANL, y-, and w-ions) could be a result of prompt radical-initiated fragmentation of hydrogen-abundant radical ions [M + H + H](+) and [M + H - H](-) within the 53 ns timeframe, which corresponds to the delayed extraction time. The further degraded fragment b/y-ions produced in the QIT cell were confirmed by positive- and negative-ion low-energy CID experiments performed on the source-generated ions (c-, z'-, and y-ions). The loss of phosphoric acid (98 u) from analyte and fragment ions can be explained by a slow ergodic fragmentation independent of positive and negative charges.

Timeframe Dependent Fragment Ions Observed in In-Source Decay Experiments with β-Casein Using MALDI MS

NASA Astrophysics Data System (ADS)

Sekiya, Sadanori; Nagoshi, Keishiro; Iwamoto, Shinichi; Tanaka, Koichi; Takayama, Mitsuo

2015-09-01

The fragment ions observed with time-of-flight (TOF) and quadrupole ion trap (QIT) TOF mass spectrometers (MS) combined with matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) experiments of phosphorylated analytes β-casein and its model peptide were compared from the standpoint of the residence timeframe of analyte and fragment ions in the MALDI ion source and QIT cell. The QIT-TOF MS gave fragment c-, z'-, z-ANL, y-, and b-ions, and further degraded fragments originating from the loss of neutrals such as H2O, NH3, CH2O (from serine), C2H4O (from threonine), and H3PO4, whereas the TOF MS merely showed MALDI source-generated fragment c-, z'-, z-ANL, y-, and w-ions. The fragment ions observed in the QIT-TOF MS could be explained by the injection of the source-generated ions into the QIT cell or a cooperative effect of a little internal energy deposition, a long residence timeframe (140 ms) in the QIT cell, and specific amino acid effects on low-energy CID, whereas the source-generated fragments (c-, z'-, z-ANL, y-, and w-ions) could be a result of prompt radical-initiated fragmentation of hydrogen-abundant radical ions [M + H + H]+ and [M + H - H]- within the 53 ns timeframe, which corresponds to the delayed extraction time. The further degraded fragment b/y-ions produced in the QIT cell were confirmed by positive- and negative-ion low-energy CID experiments performed on the source-generated ions (c-, z'-, and y-ions). The loss of phosphoric acid (98 u) from analyte and fragment ions can be explained by a slow ergodic fragmentation independent of positive and negative charges.

Monoenergetic source of kilodalton ions from Taylor cones of ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larriba, C.; Castro, S.; Fernandez de la Mora, J.

2007-04-15

The ionic liquid ion sources (ILISs) recently introduced by Lozano and Martinez Sanchez [J. Colloid Interface Sci. 282, 415 (2005)], based on electrochemically etched tungsten tips as emitters for Taylor cones of ionic liquids (ILs), have been tested with ionic liquids [A{sup +}B{sup -}] of increasing molecular weight and viscosity. These ILs have electrical conductivities well below 1 S/m and were previously thought to be unsuitable to operate in the purely ionic regime because their Taylor cones produce mostly charged drops from conventional capillary tube sources. Strikingly, all the ILs tried on ILIS form charged beams composed exclusively of smallmore » ions and cluster ions A{sup +}(AB){sub n} or B{sup -}(AB){sub n}, with abundances generally peaking at n=1. Particularly interesting are the positive and negative ion beams produced from the room temperature molten salts 1-methyl-3-pentylimidazolium tris(pentafluoroethyl) trifluorophosphate (C{sub 5}MI-(C{sub 2}F{sub 5}){sub 3}PF{sub 3}) and 1-ethyl-3-methylimidazolium bis(pentafluoroethyl) sulfonylimide (EMI-(C{sub 2}F{sub 5}SO{sub 3}){sub 2}N). We extend to these heavier species the previous conclusions from Lozano and Martinez Sanchez on the narrow energy distributions of the ion beams. In combination with suitable ILs, this source yields nanoamphere currents of positive and negative monoenergetic molecular ions with masses exceeding 2000 amu. Potential applications are in biological secondary ion mass spectrometry, chemically assisted high-resolution ion beam etching, and electrical propulsion. Advantages of the ILISs versus similar liquid metal ion sources include the possibility to form negative as well as positive ion beams and a much wider range of ion compositions and molecular masses.« less

Negative ion source with hollow cathode discharge plasma

DOEpatents

Hershcovitch, A.; Prelec, K.

1980-12-12

A negative ion source of the type where negative ions are formed by bombarding a low-work-function surface with positive ions and neutral particles from a plasma, wherein a highly ionized plasma is injected into an anode space containing the low-work-function surface is described. The plasma is formed by hollow cathode discharge and injected into the anode space along the magnetic field lines. Preferably, the negative ion source is of the magnetron type.

Prototyping of beam position monitor for medium energy beam transport section of RAON heavy ion accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Hyojae, E-mail: lkcom@ibs.re.kr; Jin, Hyunchang; Jang, Ji-Ho

2016-02-15

A heavy ion accelerator, RAON is going to be built by Rare Isotope Science Project in Korea. Its target is to accelerate various stable ions such as uranium, proton, and xenon from electron cyclotron resonance ion source and some rare isotopes from isotope separation on-line. The beam shaping, charge selection, and modulation should be applied to the ions from these ion sources because RAON adopts a superconducting linear accelerator structure for beam acceleration. For such treatment, low energy beam transport, radio frequency quadrupole, and medium energy beam transport (MEBT) will be installed in injector part of RAON accelerator. Recently, developmentmore » of a prototype of stripline beam position monitor (BPM) to measure the position of ion beams in MEBT section is under way. In this presentation, design of stripline, electromagnetic (EM) simulation results, and RF measurement test results obtained from the prototyped BPM will be described.« less

Radio frequency multicusp ion source development (invited)

NASA Astrophysics Data System (ADS)

Leung, K. N.

1996-03-01

The radio-frequency (rf) driven multicusp source was originally developed for use in the Superconducting Super Collider injector. It has been demonstrated that the source can meet the H- beam current and emittance requirements for this application. By employing a porcelain-coated antenna, a clean plasma discharge with very long-life operation can be achieved. Today, the rf source is used to generate both positive and negative hydrogen ion beams and has been tested in various particle accelerator laboratories throughout the world. Applications of this ion source have been extended to other fields such as ion beam lithography, oil-well logging, ion implantation, accelerator mass spectrometry and medical therapy machines. This paper summarizes the latest rf ion source technology and development at the Lawrence Berkeley National Laboratory.

Evaluating and Mapping of Spatial Air Ion Quality Patterns in a Residential Garden Using a Geostatistic Method

PubMed Central

Wu, Chen-Fa; Lai, Chun-Hsien; Chu, Hone-Jay; Lin, Wen-Huang

2011-01-01

Negative air ions (NAI) produce biochemical reactions that increase the levels of the mood chemical serotonin in the environment. Moreover, they benefit both the psychological well being and the human body’s physiological condition. The aim of this research was to estimate and measure the spatial distributions of negative and positive air ions in a residential garden in central Taiwan. Negative and positive air ions were measured at thirty monitoring locations in the study garden from July 2009 to June 2010. Moreover, Kriging was applied to estimate the spatial distribution of negative and positive air ions, as well as the air ion index in the study area. The measurement results showed that the numbers of NAI and PAI differed greatly during the four seasons, the highest and the lowest negative and positive air ion concentrations were found in the summer and winter, respectively. Moreover, temperature was positively affected negative air ions concentration. No matter what temperature is, the ranges of variogram in NAI/PAI were similar during four seasons. It indicated that spatial patterns of NAI/PAI were independent of the seasons and depended on garden elements and configuration, thus the NAP/PAI was a good estimate of the air quality regarding air ions. Kriging maps depicted that the highest negative and positive air ion concentration was next to the waterfall, whereas the lowest air ions areas were next to the exits of the garden. The results reveal that waterscapes are a source of negative and positive air ions, and that plants and green space are a minor source of negative air ions in the study garden. Moreover, temperature and humidity are positively and negatively affected negative air ions concentration, respectively. The proposed monitoring and mapping approach provides a way to effectively assess the patterns of negative and positive air ions in future landscape design projects. PMID:21776231

Evaluating and mapping of spatial air ion quality patterns in a residential garden using a geostatistic method.

PubMed

Wu, Chen-Fa; Lai, Chun-Hsien; Chu, Hone-Jay; Lin, Wen-Huang

2011-06-01

Negative air ions (NAI) produce biochemical reactions that increase the levels of the mood chemical serotonin in the environment. Moreover, they benefit both the psychological well being and the human body's physiological condition. The aim of this research was to estimate and measure the spatial distributions of negative and positive air ions in a residential garden in central Taiwan. Negative and positive air ions were measured at thirty monitoring locations in the study garden from July 2009 to June 2010. Moreover, Kriging was applied to estimate the spatial distribution of negative and positive air ions, as well as the air ion index in the study area. The measurement results showed that the numbers of NAI and PAI differed greatly during the four seasons, the highest and the lowest negative and positive air ion concentrations were found in the summer and winter, respectively. Moreover, temperature was positively affected negative air ions concentration. No matter what temperature is, the ranges of variogram in NAI/PAI were similar during four seasons. It indicated that spatial patterns of NAI/PAI were independent of the seasons and depended on garden elements and configuration, thus the NAP/PAI was a good estimate of the air quality regarding air ions. Kriging maps depicted that the highest negative and positive air ion concentration was next to the waterfall, whereas the lowest air ions areas were next to the exits of the garden. The results reveal that waterscapes are a source of negative and positive air ions, and that plants and green space are a minor source of negative air ions in the study garden. Moreover, temperature and humidity are positively and negatively affected negative air ions concentration, respectively. The proposed monitoring and mapping approach provides a way to effectively assess the patterns of negative and positive air ions in future landscape design projects.

Relating to monitoring ion sources

DOEpatents

Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore; Bounds, John Alan

2002-01-01

The apparatus and method provide techniques for monitoring the position on alpha contamination in or on items or locations. The technique is particularly applicable to pipes, conduits and other locations to which access is difficult. The technique uses indirect monitoring of alpha emissions by detecting ions generated by the alpha emissions. The medium containing the ions is moved in a controlled manner frog in proximity with the item or location to the detecting unit and the signals achieved over time are used to generate alpha source position information.

Experimental validation of the dual positive and negative ion beam acceleration in the plasma propulsion with electronegative gases thruster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rafalskyi, Dmytro, E-mail: dmytro.rafalskyi@lpp.polytechnique.fr; Popelier, Lara; Aanesland, Ane

The PEGASES (Plasma Propulsion with Electronegative Gases) thruster is a gridded ion thruster, where both positive and negative ions are accelerated to generate thrust. In this way, additional downstream neutralization by electrons is redundant. To achieve this, the thruster accelerates alternately positive and negative ions from an ion-ion plasma where the electron density is three orders of magnitude lower than the ion densities. This paper presents a first experimental study of the alternate acceleration in PEGASES, where SF{sub 6} is used as the working gas. Various electrostatic probes are used to investigate the source plasma potential and the energy, composition,more » and current of the extracted beams. We show here that the plasma potential control in such system is key parameter defining success of ion extraction and is sensitive to both parasitic electron current paths in the source region and deposition of sulphur containing dielectric films on the grids. In addition, large oscillations in the ion-ion plasma potential are found in the negative ion extraction phase. The oscillation occurs when the primary plasma approaches the grounded parts of the main core via sub-millimetres technological inputs. By controlling and suppressing the various undesired effects, we achieve perfect ion-ion plasma potential control with stable oscillation-free operation in the range of the available acceleration voltages (±350 V). The measured positive and negative ion currents in the beam are about 10 mA for each component at RF power of 100 W and non-optimized extraction system. Two different energy analyzers with and without magnetic electron suppression system are used to measure and compare the negative and positive ion and electron fluxes formed by the thruster. It is found that at alternate ion-ion extraction the positive and negative ion energy peaks are similar in areas and symmetrical in position with +/− ion energy corresponding to the amplitude of the applied acceleration voltage.« less

A flowing atmospheric pressure afterglow as an ion source coupled to a differential mobility analyzer for volatile organic compound detection.

PubMed

Bouza, Marcos; Orejas, Jaime; López-Vidal, Silvia; Pisonero, Jorge; Bordel, Nerea; Pereiro, Rosario; Sanz-Medel, Alfredo

2016-05-23

Atmospheric pressure glow discharges have been widely used in the last decade as ion sources in ambient mass spectrometry analyses. Here, an in-house flowing atmospheric pressure afterglow (FAPA) has been developed as an alternative ion source for differential mobility analysis (DMA). The discharge source parameters (inter-electrode distance, current and helium flow rate) determining the atmospheric plasma characteristics have been optimized in terms of DMA spectral simplicity with the highest achievable sensitivity while keeping an adequate plasma stability and so the FAPA working conditions finally selected were: 35 mA, 1 L min(-1) of He and an inter-electrode distance of 8 mm. Room temperature in the DMA proved to be adequate for the coupling and chemical analysis with the FAPA source. Positive and negative ions for different volatile organic compounds were tested and analysed by FAPA-DMA using a Faraday cup as a detector and proper operation in both modes was possible (without changes in FAPA operational parameters). The FAPA ionization source showed simpler ion mobility spectra with narrower peaks and a better, or similar, sensitivity than conventional UV-photoionization for DMA analysis in positive mode. Particularly, the negative mode proved to be a promising field of further research for the FAPA ion source coupled to ion mobility, clearly competitive with other more conventional plasmas such as corona discharge.

DUHOCAMIS: a dual hollow cathode ion source for metal ion beams.

PubMed

Zhao, W J; Müller, M W O; Janik, J; Liu, K X; Ren, X T

2008-02-01

In this paper we describe a novel ion source named DUHOCAMIS for multiply charged metal ion beams. This ion source is derived from the hot cathode Penning ion gauge ion source (JINR, Dubna, 1957). A notable characteristic is the modified Penning geometry in the form of a hollow sputter electrode, coaxially positioned in a compact bottle-magnetic field along the central magnetic line of force. The interaction of the discharge geometry with the inhomogeneous but symmetrical magnetic field enables this device to be operated as hollow cathode discharge and Penning discharge as well. The main features of the ion source are the very high metal ion efficiency (up to 25%), good operational reproducibility, flexible and efficient operations for low charged as well as highly charged ions, compact setup, and easy maintenance. For light ions, e.g., up to titanium, well-collimated beams in the range of several tens of milliamperes of pulsed ion current (1 ms, 10/s) have been reliably performed in long time runs.

Plasma formed ion beam projection lithography system

DOEpatents

Leung, Ka-Ngo; Lee, Yung-Hee Yvette; Ngo, Vinh; Zahir, Nastaran

2002-01-01

A plasma-formed ion-beam projection lithography (IPL) system eliminates the acceleration stage between the ion source and stencil mask of a conventional IPL system. Instead a much thicker mask is used as a beam forming or extraction electrode, positioned next to the plasma in the ion source. Thus the entire beam forming electrode or mask is illuminated uniformly with the source plasma. The extracted beam passes through an acceleration and reduction stage onto the resist coated wafer. Low energy ions, about 30 eV, pass through the mask, minimizing heating, scattering, and sputtering.

Ionization source utilizing a jet disturber in combination with an ion funnel and method of operation

DOEpatents

Smith, Richard D.; Kim, Taeman; Tang, Keqi; Udseth, Harold R.

2003-06-24

A jet disturber used in combination with an ion funnel to focus ions and other charged particles generated at or near atmospheric pressure into a relatively low pressure region, which allows increased conductance of the ions and other charged particles. The jet disturber is positioned within an ion funnel and may be interfaced with a multi-capillary inlet juxtaposed between an ion source and the interior of an instrument maintained at near atmospheric pressure. The invention finds particular advantages when deployed to improve the ion transmission between an electrospray ionization source and the first vacuum stage of a mass spectrometer.

Development of Remote Sampling ESI Mass Spectrometry for the Rapid and Automatic Analysis of Multiple Samples

PubMed Central

Yamada, Yuki; Ninomiya, Satoshi; Hiraoka, Kenzo; Chen, Lee Chuin

2016-01-01

We report on combining a self-aspirated sampling probe and an ESI source using a single metal capillary which is electrically grounded and safe for use by the operator. To generate an electrospray, a negative H.V. is applied to the counter electrode of the ESI emitter to operate in positive ion mode. The sampling/ESI capillary is enclosed within another concentric capillary similar to the arrangement for a standard pneumatically assisted ESI source. The suction of the liquid sample is due to the Venturi effect created by the high-velocity gas flow near the ESI tip. In addition to serving as the mechanism for suction, the high-velocity gas flow also assists in the nebulization of charged droplets, thus producing a stable ion signal. Even though the potential of the ion source counter electrode is more negative than the mass spectrometer in the positive ion mode, the electric field effect is not significant if the ion source and the mass spectrometer are separated by a sufficient distance. Ion transmission is achieved by the viscous flow of the carrier gas. Using the present arrangement, the user can hold the ion source in a bare hand and the ion signal appears almost immediately when the sampling capillary is brought into contact with the liquid sample. The automated analysis of multiple samples can also be achieved by using motorized sample stage and an automated ion source holder. PMID:28616373

Development of Remote Sampling ESI Mass Spectrometry for the Rapid and Automatic Analysis of Multiple Samples.

PubMed

Yamada, Yuki; Ninomiya, Satoshi; Hiraoka, Kenzo; Chen, Lee Chuin

2016-01-01

We report on combining a self-aspirated sampling probe and an ESI source using a single metal capillary which is electrically grounded and safe for use by the operator. To generate an electrospray, a negative H.V. is applied to the counter electrode of the ESI emitter to operate in positive ion mode. The sampling/ESI capillary is enclosed within another concentric capillary similar to the arrangement for a standard pneumatically assisted ESI source. The suction of the liquid sample is due to the Venturi effect created by the high-velocity gas flow near the ESI tip. In addition to serving as the mechanism for suction, the high-velocity gas flow also assists in the nebulization of charged droplets, thus producing a stable ion signal. Even though the potential of the ion source counter electrode is more negative than the mass spectrometer in the positive ion mode, the electric field effect is not significant if the ion source and the mass spectrometer are separated by a sufficient distance. Ion transmission is achieved by the viscous flow of the carrier gas. Using the present arrangement, the user can hold the ion source in a bare hand and the ion signal appears almost immediately when the sampling capillary is brought into contact with the liquid sample. The automated analysis of multiple samples can also be achieved by using motorized sample stage and an automated ion source holder.

A Novel Microwave-Induced Plasma Ionization Source for Ion Mobility Spectrometry

NASA Astrophysics Data System (ADS)

Dai, Jianxiong; Zhao, Zhongjun; Liang, Gaoling; Duan, Yixiang

2017-03-01

This work demonstrates the application of a novel microwave induced plasma ionization (MIPI) source to ion mobility spectrometry (IMS). The MIPI source, called Surfatron, is composed of a copper cavity and a hollow quartz discharge tube. The ion mobility spectrum of synthetics air has a main peak with reduced mobility of 2.14 cm2V-1s-1 for positive ion mode and 2.29 cm2V-1s-1 for negative ion mode. The relative standard deviations (RSD) are 0.7% and 1.2% for positive and negative ion mode, respectively. The total ion current measured was more than 3.5 nA, which is much higher than that of the conventional 63Ni source. This indicates that a better signal-to-noise ratio (SNR) can be acquired from the MIPI source. The SNR was 110 in the analysis of 500 pptv methyl tert-butyl ether (MTBE), resulting in the limit of detection (SNR = 3) of 14 pptv. The linear range covers close to 2.5 orders of magnitude in the detection of triethylamine with a concentration range from 500 pptv to 80 ppbv. Finally, this new MIPI-IMS was used to detect some volatile organic compounds, which demonstrated that the MIPI-IMS has great potential in monitoring pollutants in air.

Ion funnel device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibrahim, Yehia M.; Chen, Tsung-Chi; Harrer, Marques B.

2017-11-21

An ion funnel device is disclosed. A first pair of electrodes is positioned in a first direction. A second pair of electrodes is positioned in a second direction. The device includes an RF voltage source and a DC voltage source. A RF voltage with a superimposed DC voltage gradient is applied to the first pair of electrodes, and a DC voltage gradient is applied to the second pair of electrodes.

Negative ion source with external RF antenna

DOEpatents

Leung, Ka-Ngo; Hahto, Sami K.; Hahto, Sari T.

2007-02-13

A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source. A converter can be included in the ion source to produce negative ions.

Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurisu, Yosuke; Kiriyama, Ryutaro; Takenaka, Tomoya

2012-02-15

We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I{sub FC} by the mobile plate tuner. The I{sub FC} is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I{sub FC} and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasmamore » density contributes largely to the variation of the I{sub FC} when we change the position of the mobile plate tuner.« less

A Microwave Driven Ion Source for Continuous-Flow AMS (Abstract)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wills, J.; Schneider, R.J.; Reden, K.F. von

2005-03-15

A microwave-driven, gas-fed ion source originally developed as a high-current positive ion injector for a Tandem accelerator at Chalk River has been the subject of a three-year development program at the Woods Hole Oceanographic Institution NOSAMS facility. Off-line tests have demonstrated positive carbon currents of 1 mA and negative carbon currents of 80 {mu}A from CO2 gas feed. This source and a magnesium charge-exchange canal were coupled to the recombinator of the NOSAMS Tandetron for on-line tests, with the source fed with reference gasses and a combustion device.The promising results obtained have prompted the redesign of the microwave source formore » use as an on-line, continuous-flow injector for a new AMS facility under construction at NOSAMS. The new design is optimized for best transmission of the extracted positive-ion beam through the charge-exchange canal and for reliable operation at 40 kV extraction voltage. Other goals of the re-design include improved lifetime of the microwave window and the elimination of dead volumes in the plasma generator that increase sample hold-up time.This talk will include a summary of results obtained to date at NOSAMS with the Chalk River source and a detailed description of the new design.« less

Modeling of surface-dominated plasmas: from electric thruster to negative ion source.

PubMed

Taccogna, F; Schneider, R; Longo, S; Capitelli, M

2008-02-01

This contribution shows two important applications of the particle-in-cell/monte Carlo technique on ion sources: modeling of the Hall thruster SPT-100 for space propulsion and of the rf negative ion source for ITER neutral beam injection. In the first case translational degrees of freedom are involved, while in the second case inner degrees of freedom (vibrational levels) are excited. Computational results show how in both cases, plasma-wall and gas-wall interactions play a dominant role. These are secondary electron emission from the lateral ceramic wall of SPT-100 and electron capture from caesiated surfaces by positive ions and atoms in the rf negative ion source.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Z; Jiang, W; Stuart, B

Purpose: Since electrons are easily scattered, the virtual source position for electrons is expected to locate below the x-ray target of Medical Linacs. However, the effective SSD method yields the electron virtual position above the x-ray target for some applicators for some energy in Siemens Linacs. In this study, we propose to use IC Profiler (Sun Nuclear) for evaluating the electron virtual source position for the standard electron applicators for various electron energies. Methods: The profile measurements for various nominal source-to-detector distances (SDDs) of 100–115 cm were carried out for electron beam energies of 6–18 MeV. Two methods were used:more » one was to use a 0.125 cc ion chamber (PTW, Type 31010) with buildup mounted in a PTW water tank without water filled; and the other was to use IC Profiler with a buildup to achieve charge particle equilibrium. The full width at half-maximum (FWHM) method was used to determine the field sizes for the measured profiles. Backprojecting (by a straight line) the distance between the 50% points on the beam profiles for the various SDDs, yielded the virtual source position for each applicator. Results: The profiles were obtained and the field sizes were determined by FWHM. The virtual source positions were determined through backprojection of profiles for applicators (5, 10, 15, 20, 25). For instance, they were 96.415 cm (IC Profiler) vs 95.844 cm (scanning ion chamber) for 9 MeV electrons with 10×10 cm applicator and 97.160 cm vs 97.161 cm for 12 MeV electrons with 10×10 cm applicator. The differences in the virtual source positions between IC profiler and scanning ion chamber were within 1.5%. Conclusion: IC Profiler provides a practical method for determining the electron virtual source position and its results are consistent with those obtained by profiles of scanning ion chamber with buildup.« less

Overview of the design of the ITER heating neutral beam injectors

NASA Astrophysics Data System (ADS)

Hemsworth, R. S.; Boilson, D.; Blatchford, P.; Dalla Palma, M.; Chitarin, G.; de Esch, H. P. L.; Geli, F.; Dremel, M.; Graceffa, J.; Marcuzzi, D.; Serianni, G.; Shah, D.; Singh, M.; Urbani, M.; Zaccaria, P.

2017-02-01

The heating neutral beam injectors (HNBs) of ITER are designed to deliver 16.7 MW of 1 MeV D0 or 0.87 MeV H0 to the ITER plasma for up to 3600 s. They will be the most powerful neutral beam (NB) injectors ever, delivering higher energy NBs to the plasma in a tokamak for longer than any previous systems have done. The design of the HNBs is based on the acceleration and neutralisation of negative ions as the efficiency of conversion of accelerated positive ions is so low at the required energy that a realistic design is not possible, whereas the neutralisation of H- and D- remains acceptable (≈56%). The design of a long pulse negative ion based injector is inherently more complicated than that of short pulse positive ion based injectors because: • negative ions are harder to create so that they can be extracted and accelerated from the ion source; • electrons can be co-extracted from the ion source along with the negative ions, and their acceleration must be minimised to maintain an acceptable overall accelerator efficiency; • negative ions are easily lost by collisions with the background gas in the accelerator; • electrons created in the extractor and accelerator can impinge on the extraction and acceleration grids, leading to high power loads on the grids; • positive ions are created in the accelerator by ionisation of the background gas by the accelerated negative ions and the positive ions are back-accelerated into the ion source creating a massive power load to the ion source; • electrons that are co-accelerated with the negative ions can exit the accelerator and deposit power on various downstream beamline components. The design of the ITER HNBs is further complicated because ITER is a nuclear installation which will generate very large fluxes of neutrons and gamma rays. Consequently all the injector components have to survive in that harsh environment. Additionally the beamline components and the NB cell, where the beams are housed, will be activated and all maintenance will have to be performed remotely. This paper describes the design of the HNB injectors, but not the associated power supplies, cooling system, cryogenic system etc, or the high voltage bushing which separates the vacuum of the beamline from the high pressure SF6 of the high voltage (1 MV) transmission line, through which the power, gas and cooling water are supplied to the beam source. Also the magnetic field reduction system is not described.

Characterization and Performance of a High-Current-Density Ion Implanter with Magnetized Hollow-Cathode Plasma Source

NASA Astrophysics Data System (ADS)

Falkenstein, Zoran; Rej, Donald; Gavrilov, Nikolai

1998-10-01

In a collaboration between the Institute of Electrophysics (IEP) and the Los Alamos National Laboratory (LANL), the IEP has developed an industrial scalable, high-power, large-area ion source for the surface modification of materials. The plasma source of the ion beam source can be described as a pulsed glow discharge with a cold, hollow-cathode in a weak magnetic field. Extraction and focusing of positive ions by an acceleration and ion-optical plate system renders the generation of a homogeneous, large-area ion beam with an averaged total ion current of up to 50 mA at acceleration voltages of up to 50 kV. The principle set-up of the ion beam source as well as some electrical characteristics (gas discharge current and the extracted ion beam current) are presented for a lab-scale prototype. Measurements of the radial ion current density profiles within the ion beam for various discharge parameters, as well as results on surface modification by ion implantation of nitrogen into aluminum and chromium are presented. Finally, a comparison of the applied ion dose with the retained ion doses is given.

Investigation of high duty factor ISR RFQ-1000

NASA Astrophysics Data System (ADS)

Lu, Y. R.; Chen, C. E.; Fang, J. X.; Gao, S. L.; Guo, J. F.; Guo, Z. Y.; Li, D. S.; Li, W. G.; Pan, O. J.; Ren, X. T.; Wu, Y.; Yan, X. Q.; Yu, J. X.; Yu, M. L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

2003-12-01

Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O+ and negative O- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O- beam current reached 660 μA at a transmission efficiency of more than 82%. The N+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper.

Negative ion MALDI-TOF MS, ISD and PSD of neutral underivatized oligosaccharides without anionic dopant strategies, using 2,5-DHAP as a matrix.

PubMed

Jovanović, Marko; Peter-Katalinić, Jasna

2016-02-01

Oligosaccharides represent complex class of analytes for mass spectrometric analysis due to the high variety of structural isomers concerning glycosidic linkages and possible branching. A systematic study of the negative ion mode matrix-assisted laser desorption/ionization (MALDI) mass spectrometry of various neutral oligosaccharides under selection of an appropriate matrix, like 2,5-dihydroxyacetophenone (2,5-DHAP) is reported here, without commonly used anion dopant strategies. Nevertheless, we were able to generate relevant in-source decay (ISD) cross-ring fragment ions, typically obtained in the negative ion mode. Data observed indicate that the intrinsic property of the terminal non-reduced aldose is crucial for this behavior. A systematic study of the post source decay (PSD) of molecular, pseudomolecular and ISD cross-ring cleavage precursor ions is reported here. A direct comparison of the positive and negative ion mode MALDI MS1 and PSD behavior of neutral oligosaccharides could also be performed under the use of the same matrix preparation, because 2,5-DHAP is fully compatible with positive ion mode acquisition. We found that PSD spectra of deprotonated neutral oligosaccharides obtained in the negative ion mode are richer, because they contained both glycosidic and cross-ring fragment ions. However, we also found that cross-ring fragment ions are readily produced in the positive ion mode when potassiated precursor ions were selected. In addition, we show evidence that non-anionic dopants and specific instrumental parameters can also significantly influence the ISD fragmentation. Taken together, our results should increase our understanding of oligosaccharide behavior in the negative ion mode as well as increase our knowledge regarding many aspects of in-source MALDI chemistry. Copyright © 2016 John Wiley & Sons, Ltd.

Negative ion-driven associated particle neutron generator

DOE PAGES

Antolak, A. J.; Leung, K. N.; Morse, D. H.; ...

2015-10-09

We describe an associated particle neutron generator that employs a negative ion source to produce high neutron flux from a small source size. Furthermore, negative ions produced in an rf-driven plasma source are extracted through a small aperture to form a beam which bombards a positively biased, high voltage target electrode. Electrons co-extracted with the negative ions are removed by a permanent magnet electron filter. The use of negative ions enables high neutron output (100% atomic ion beam), high quality imaging (small neutron source size), and reliable operation (no high voltage breakdowns). Finally, the neutron generator can operate in eithermore » pulsed or continuous-wave (cw) mode and has been demonstrated to produce 10 6 D-D n/s (equivalent to similar to 10 8 D-T n/s) from a 1 mm-diameter neutron source size to facilitate high fidelity associated particle imaging.« less

Detection of positive and negative ions from a flowing atmospheric pressure afterglow using a Mattauch-Herzog mass spectrograph equipped with a Faraday-strip array detector.

PubMed

Schilling, Gregory D; Shelley, Jacob T; Barnes, James H; Sperline, Roger P; Denton, M Bonner; Barinaga, Charles J; Koppenaal, David W; Hieftje, Gary M

2010-01-01

An ambient desorption/ionization (ADI) source, known as the flowing atmospheric pressure afterglow (FAPA), has been coupled to a Mattauch-Herzog mass spectrograph (MHMS) equipped with a focal plane camera (FPC) array detector. The FAPA ionization source enables direct mass spectral analysis of solids, liquids, and gases through either positive or negative ionization modes. In either case, spectra are generally simple with dominant peaks being the molecular ions or protonated molecular ions. Use of the FAPA source with the MHMS allows the FPC detector to be characterized for the determination of molecular species, whereas previously only atomic mass spectrometry (MS) has been demonstrated. Furthermore, the FPC is shown to be sensitive to negative ions without the need to change any detector parameters. The analysis of solid, liquid, and gaseous samples through positive and negative ionization is demonstrated with detection limits (1-25 fmol/s, approximately 0.3-10 pg of analyte per mL of helium) surpassing those obtained with the FAPA source coupled to a time-of-flight mass analyzer. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

Ion source with external RF antenna

DOEpatents

Leung, Ka-Ngo; Ji, Qing; Wilde, Stephen

2005-12-13

A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to mount the external RF antenna to the ion source. The RF antenna tubing is wound around the external RF antenna assembly to form a coil. The external RF antenna assembly is formed of a material, e.g. quartz, which is essentially transparent to the RF waves. The external RF antenna assembly is attached to and forms a part of the plasma source chamber so that the RF waves emitted by the RF antenna enter into the inside of the plasma chamber and ionize a gas contained therein. The plasma ion source is typically a multi-cusp ion source.

Selective ion source

DOEpatents

Leung, K.N.

1996-05-14

A ion source is described wherein selected ions maybe extracted to the exclusion of unwanted ion species of higher ionization potential. Also described is a method of producing selected ions from a compound, such as P{sup +} from PH{sub 3}. The invention comprises a plasma chamber, an electron source, a means for introducing a gas to be ionized by electrons from the electron source, means for limiting electron energy from the electron source to a value between the ionization energy of the selected ion species and the greater ionization energy of an unwanted ion specie, and means for extracting the target ion specie from the plasma chamber. In one embodiment, the electrons are generated in a plasma cathode chamber immediately adjacent to the plasma chamber. A small extractor draws the electrons from the plasma cathode chamber into the relatively positive plasma chamber. The energy of the electrons extracted in this manner is easily controlled. The invention is particularly useful for doping silicon with P{sup +}, As{sup +}, and B{sup +} without the problematic presence of hydrogen, helium, water, or carbon oxide ions. Doped silicon is important for manufacture of semiconductors and semiconductor devices. 6 figs.

Selective ion source

DOEpatents

Leung, Ka-Ngo

1996-01-01

A ion source is described wherein selected ions maybe extracted to the exclusion of unwanted ion species of higher ionization potential. Also described is a method of producing selected ions from a compound, such as P.sup.+ from PH.sub.3. The invention comprises a plasma chamber, an electron source, a means for introducing a gas to be ionized by electrons from the electron source, means for limiting electron energy from the electron source to a value between the ionization energy of the selected ion species and the greater ionization energy of an unwanted ion specie, and means for extracting the target ion specie from the plasma chamber. In one embodiment, the electrons are generated in a plasma cathode chamber immediately adjacent to the plasma chamber. A small extractor draws the electrons from the plasma cathode chamber into the relatively positive plasma chamber. The energy of the electrons extracted in this manner is easily controlled. The invention is particularly useful for doping silicon with P.sup.+, AS.sup.+, and B.sup.+ without the problematic presence of hydrogen, helium, water, or carbon oxide ions. Doped silicon is important for manufacture of semiconductors and semiconductor devices.

Tests of positive ion beams from a microwave ion source for AMS

NASA Astrophysics Data System (ADS)

Schneider, R. J.; von Reden, K. F.; Hayes, J. M.; Wills, J. S. C.; Kern, W. G. E.; Kim, S.-W.

2000-10-01

A test facility has been constructed to evaluate high-current positive ion beams from small gaseous samples for AMS applications. The major components include a compact permanent magnet microwave ion source built at the AECL Chalk River Laboratory and now on loan from the University of Toronto, and a double-focusing spectrometer magnet on loan from Argonne National Laboratory. Samples are introduced by means of a silica capillary injection system. Loop injection into a carrier gas provides a stable feed for the microwave driven plasma. The magnetic analysis system is utilized to isolate carbon ions derived from CO 2 samples from other products of the plasma discharge, including argon ions of the carrier gas. With a smaller discharge chamber, we hope to exceed a conversion efficiency of 14% for carbon ions produced per atom, which we reported at AMS-7. The next step will be to construct an efficient charge-exchange cell, to produce negative ions for injection into the WHOI recombinator injector.

Improvement of uniformity of the negative ion beams by tent-shaped magnetic field in the JT-60 negative ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshida, Masafumi, E-mail: yoshida.masafumi@jaea.go.jp; Hanada, Masaya; Kojima, Atsushi

2014-02-15

Non-uniformity of the negative ion beams in the JT-60 negative ion source with the world-largest ion extraction area was improved by modifying the magnetic filter in the source from the plasma grid (PG) filter to a tent-shaped filter. The magnetic design via electron trajectory calculation showed that the tent-shaped filter was expected to suppress the localization of the primary electrons emitted from the filaments and created uniform plasma with positive ions and atoms of the parent particles for the negative ions. By modifying the magnetic filter to the tent-shaped filter, the uniformity defined as the deviation from the averaged beammore » intensity was reduced from 14% of the PG filter to ∼10% without a reduction of the negative ion production.« less

Supersonic Bare Metal Cluster Beams. Technical Progress Report, March 16, 1984 - April 1, 1985

DOE R&D Accomplishments Database

Smalley, R. E.

1985-01-01

There have been four major areas of concentration for the study of bare metal cluster beams: neutral cluster, chemical reactivity, cold cluster ion source development (both positive and negative), bare cluster ion ICR (ion cyclotron resonance) development, and photofragmentation studies of bare metal cluster ions.

Performance of the rebuilt SUERC single-stage accelerator mass spectrometer

NASA Astrophysics Data System (ADS)

Shanks, Richard P.; Ascough, Philippa L.; Dougans, Andrew; Gallacher, Paul; Gulliver, Pauline; Rood, Dylan H.; Xu, Sheng; Freeman, Stewart P. H. T.

2015-10-01

The SUERC bipolar single-stage accelerator mass spectrometer (SSAMS) has been dismantled and rebuilt to accommodate an additional rotatable pre-accelerator electrostatic spherical analyser (ESA) and a second ion source injector. This is for the attachment of an experimental positive-ion electron cyclotron resonance (ECR) ion source in addition to a Cs-sputter source. The ESA significantly suppresses oxygen interference to radiocarbon detection, and remaining measurement interference is now thought to be from 13C injected as 13CH molecule scattering off the plates of a second original pre-detector ESA.

Development of a helicon ion source: Simulations and preliminary experiments.

PubMed

Afsharmanesh, M; Habibi, M

2018-03-01

In the present context, the extraction system of a helicon ion source has been simulated and constructed. Results of the ion source commissioning at up to 20 kV are presented as well as simulations of an ion beam extraction system. Argon current of more than 200 μA at up to 20 kV is extracted and is characterized with a Faraday cup and beam profile monitoring grid. By changing different ion source parameters such as RF power, extraction voltage, and working pressure, an ion beam with current distribution exhibiting a central core has been detected. Jump transition of ion beam current emerges at the RF power near to 700 W, which reveals that the helicon mode excitation has reached this power. Furthermore, measuring the emission line intensity of Ar ii at 434.8 nm is the other way we have used for demonstrating the mode transition from inductively coupled plasma to helicon. Due to asymmetrical longitudinal power absorption of a half-helix helicon antenna, it is used for the ion source development. The modeling of the plasma part of the ion source has been carried out using a code, HELIC. Simulations are carried out by taking into account a Gaussian radial plasma density profile and for plasma densities in range of 10 18 -10 19 m -3 . Power absorption spectrum and the excited helicon mode number are obtained. Longitudinal RF power absorption for two different antenna positions is compared. Our results indicate that positioning the antenna near to the plasma electrode is desirable for the ion beam extraction. The simulation of the extraction system was performed with the ion optical code IBSimu, making it the first helicon ion source extraction designed with the code. Ion beam emittance and Twiss parameters of the ellipse emittance are calculated at different iterations and mesh sizes, and the best values of the mesh size and iteration number have been obtained for the calculations. The simulated ion beam extraction system has been evaluated using optimized parameters such as the gap distance between electrodes, electrodes aperture, and extraction voltage. The gap distance, ground electrode aperture, and extraction voltage have been changed between 3 and 9 mm, 2-6.5 mm, and 10-35 kV in the simulations, respectively.

Development of a helicon ion source: Simulations and preliminary experiments

NASA Astrophysics Data System (ADS)

Afsharmanesh, M.; Habibi, M.

2018-03-01

In the present context, the extraction system of a helicon ion source has been simulated and constructed. Results of the ion source commissioning at up to 20 kV are presented as well as simulations of an ion beam extraction system. Argon current of more than 200 μA at up to 20 kV is extracted and is characterized with a Faraday cup and beam profile monitoring grid. By changing different ion source parameters such as RF power, extraction voltage, and working pressure, an ion beam with current distribution exhibiting a central core has been detected. Jump transition of ion beam current emerges at the RF power near to 700 W, which reveals that the helicon mode excitation has reached this power. Furthermore, measuring the emission line intensity of Ar ii at 434.8 nm is the other way we have used for demonstrating the mode transition from inductively coupled plasma to helicon. Due to asymmetrical longitudinal power absorption of a half-helix helicon antenna, it is used for the ion source development. The modeling of the plasma part of the ion source has been carried out using a code, HELIC. Simulations are carried out by taking into account a Gaussian radial plasma density profile and for plasma densities in range of 1018-1019 m-3. Power absorption spectrum and the excited helicon mode number are obtained. Longitudinal RF power absorption for two different antenna positions is compared. Our results indicate that positioning the antenna near to the plasma electrode is desirable for the ion beam extraction. The simulation of the extraction system was performed with the ion optical code IBSimu, making it the first helicon ion source extraction designed with the code. Ion beam emittance and Twiss parameters of the ellipse emittance are calculated at different iterations and mesh sizes, and the best values of the mesh size and iteration number have been obtained for the calculations. The simulated ion beam extraction system has been evaluated using optimized parameters such as the gap distance between electrodes, electrodes aperture, and extraction voltage. The gap distance, ground electrode aperture, and extraction voltage have been changed between 3 and 9 mm, 2-6.5 mm, and 10-35 kV in the simulations, respectively.

Electron temperature profiles in axial field 2.45 GHz ECR ion source with a ceramic chamber

NASA Astrophysics Data System (ADS)

Abe, K.; Tamura, R.; Kasuya, T.; Wada, M.

2017-08-01

An array of electrostatic probes was arranged on the plasma electrode of a 2.45 GHz microwave driven axial magnetic filter field type negative hydrogen (H-) ion source to clarify the spatial plasma distribution near the electrode. The measured spatial distribution of electron temperature indicated the lower temperature near the extraction hole of the plasma electrode corresponding to the effectiveness of the axial magnetic filter field geometry. When the ratio of electron saturation current to the ion saturation current was plotted as a function of position, the obtained distribution showed a higher ratio near the hydrogen gas inlet through which ground state hydrogen molecules are injected into the source. Though the efficiency in producing H- ions is smaller for a 2.45 GHz source than a source operated at 14 GHz, it gives more volume to measure spatial distributions of various plasma parameters to understand fundamental processes that are influential on H- production in this type of ion sources.

Ion source based on the cathodic arc

DOEpatents

Sanders, David M.; Falabella, Steven

1994-01-01

A cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated. An array of electrically isolated rings positioned in the source serves the dual purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles.

Development of a compact ECR ion source for various ion production.

PubMed

Muramatsu, M; Hojo, S; Iwata, Y; Katagiri, K; Sakamoto, Y; Takahashi, N; Sasaki, N; Fukushima, K; Takahashi, K; Suzuki, T; Sasano, T; Uchida, T; Yoshida, Y; Hagino, S; Nishiokada, T; Kato, Y; Kitagawa, A

2016-02-01

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute of Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.

Development of a compact ECR ion source for various ion production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muramatsu, M., E-mail: m-mura@nirs.go.jp; Hojo, S.; Iwata, Y.

2016-02-15

There is a desire that a carbon-ion radiotherapy facility will produce various ion species for fundamental research. Although the present Kei2-type ion sources are dedicated for the carbon-ion production, a future ion source is expected that could provide: (1) carbon-ion production for medical use, (2) various ions with a charge-to-mass ratio of 1/3 for the existing Linac injector, and (3) low cost for modification. A prototype compact electron cyclotron resonance (ECR) ion source, named Kei3, based on the Kei series has been developed to correspond to the Kei2 type and to produce these various ions at the National Institute ofmore » Radiological Sciences (NIRS). The Kei3 has an outer diameter of 280 mm and a length of 1120 mm. The magnetic field is formed by the same permanent magnet as Kei2. The movable extraction electrode has been installed in order to optimize the beam extraction with various current densities. The gas-injection side of the vacuum chamber has enough space for an oven system. We measured dependence of microwave frequency, extraction voltage, and puller position. Charge state distributions of helium, carbon, nitrogen, oxygen, and neon were also measured.« less

Charge neutralization apparatus for ion implantation system

DOEpatents

Leung, Ka-Ngo; Kunkel, Wulf B.; Williams, Malcom D.; McKenna, Charles M.

1992-01-01

Methods and apparatus for neutralization of a workpiece such as a semiconductor wafer in a system wherein a beam of positive ions is applied to the workpiece. The apparatus includes an electron source for generating an electron beam and a magnetic assembly for generating a magnetic field for guiding the electron beam to the workpiece. The electron beam path preferably includes a first section between the electron source and the ion beam and a second section which is coincident with the ion beam. The magnetic assembly generates an axial component of magnetic field along the electron beam path. The magnetic assembly also generates a transverse component of the magnetic field in an elbow region between the first and second sections of the electron beam path. The electron source preferably includes a large area lanthanum hexaboride cathode and an extraction grid positioned in close proximity to the cathode. The apparatus provides a high current, low energy electron beam for neutralizing charge buildup on the workpiece.

Upgrade of the BATMAN test facility for H- source development

NASA Astrophysics Data System (ADS)

Heinemann, B.; Fröschle, M.; Falter, H.-D.; Fantz, U.; Franzen, P.; Kraus, W.; Nocentini, R.; Riedl, R.; Ruf, B.

2015-04-01

The development of a radio frequency (RF) driven source for negative hydrogen ions for the neutral beam heating devices of fusion experiments has been successfully carried out at IPP since 1996 on the test facility BATMAN. The required ITER parameters have been achieved with the prototype source consisting of a cylindrical driver on the back side of a racetrack like expansion chamber. The extraction system, called "Large Area Grid" (LAG) was derived from a positive ion accelerator from ASDEX Upgrade (AUG) using its aperture size (ø 8 mm) and pattern but replacing the first two electrodes and masking down the extraction area to 70 cm2. BATMAN is a well diagnosed and highly flexible test facility which will be kept operational in parallel to the half size ITER source test facility ELISE for further developments to improve the RF efficiency and the beam properties. It is therefore planned to upgrade BATMAN with a new ITER-like grid system (ILG) representing almost one ITER beamlet group, namely 5 × 14 apertures (ø 14 mm). Additionally to the standard three grid extraction system a repeller electrode upstream of the grounded grid can optionally be installed which is positively charged against it by 2 kV. This is designated to affect the onset of the space charge compensation downstream of the grounded grid and to reduce the backstreaming of positive ions from the drift space backwards into the ion source. For magnetic filter field studies a plasma grid current up to 3 kA will be available as well as permanent magnets embedded into a diagnostic flange or in an external magnet frame. Furthermore different source vessels and source configurations are under discussion for BATMAN, e.g. using the AUG type racetrack RF source as driver instead of the circular one or modifying the expansion chamber for a more flexible position of the external magnet frame.

Pressure dependence of an ion beam accelerating structure in an expanding helicon plasma

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Aguirre, Evan; Thompson, Derek S.; McKee, John; Henriquez, Miguel; Scime, Earl E.

2018-02-01

We present measurements of the parallel ion velocity distribution function and electric field in an expanding helicon source plasma plume as a function of downstream gas pressure and radial and axial positions. The ion beam that appears spontaneously in the plume persists for all downstream pressures investigated, with the largest parallel ion beam velocities obtained for the lowest downstream pressures. However, the change in ion beam velocity exceeds what would be expected simply for a change in the collisionality of the system. Electric field measurements confirm that it is the magnitude of the potential structure responsible for accelerating the ion beam that changes with downstream pressure. Interestingly, the ion density radial profile is hollow close to the end of the plasma source for all pressures, but it is hollow at downstream distances far from the source only at the highest downstream neutral pressures.

Linear electronic field time-of-flight ion mass spectrometers

DOEpatents

Funsten, Herbert O.

2010-08-24

Time-of-flight mass spectrometer comprising a first drift region and a second drift region enclosed within an evacuation chamber; a means of introducing an analyte of interest into the first drift region; a pulsed ionization source which produces molecular ions from said analyte of interest; a first foil positioned between the first drift region and the second drift region, which dissociates said molecular ions into constituent atomic ions and emits secondary electrons; an electrode which produces secondary electrons upon contact with a constituent atomic ion in second drift region; a stop detector comprising a first ion detection region and a second ion detection region; and a timing means connected to the pulsed ionization source, to the first ion detection region, and to the second ion detection region.

Breakthrough in 4π ion emission mechanism understanding in plasma focus devices.

PubMed

Sohrabi, Mehdi; Zarinshad, Arefe; Habibi, Morteza

2016-12-12

Ion emission angular distribution mechanisms in plasma focus devices (PFD) have not yet been well developed and understood being due to the lack of an efficient wide-angle ion distribution image detection system to characterize a PFD space in detail. Present belief is that the acceleration of ions points from "anode top" upwards in forward direction within a small solid angle. A breakthrough is reported in this study, by mega-size position-sensitive polycarbonate ion image detection systems invented, on discovery of 4π ion emission from the "anode top" in a PFD space after plasma pinch instability and radial run-away of ions from the "anode cathodes array" during axial acceleration of plasma sheaths before the radial phase. These two ion emission source mechanisms behave respectively as a "Point Ion Source" and a "Line Ion Source" forming "Ion Cathode Shadows" on mega-size detectors. We believe that the inventions and discoveries made here will open new horizons for advanced ion emission studies towards better mechanisms understanding and in particular will promote efficient applications of PFDs in medicine, science and technology.

RF Negative Ion Source Development at IPP Garching

NASA Astrophysics Data System (ADS)

Kraus, W.; McNeely, P.; Berger, M.; Christ-Koch, S.; Falter, H. D.; Fantz, U.; Franzen, P.; Fröschle, M.; Heinemann, B.; Leyer, S.; Riedl, R.; Speth, E.; Wünderlich, D.

2007-08-01

IPP Garching is heavily involved in the development of an ion source for Neutral Beam Heating of the ITER Tokamak. RF driven ion sources have been successfully developed and are in operation on the ASDEX-Upgrade Tokamak for positive ion based NBH by the NB Heating group at IPP Garching. Building on this experience a RF driven H- ion source has been under development at IPP Garching as an alternative to the ITER reference design ion source. The number of test beds devoted to source development for ITER has increased from one (BATMAN) by the addition of two test beds (MANITU, RADI). This paper contains descriptions of the three test beds. Results on diagnostic development using laser photodetachment and cavity ringdown spectroscopy are given for BATMAN. The latest results for long pulse development on MANITU are presented including the to date longest pulse (600 s). As well, details of source modifications necessitated for pulses in excess of 100 s are given. The newest test bed RADI is still being commissioned and only technical details of the test bed are included in this paper. The final topic of the paper is an investigation into the effects of biasing the plasma grid.

Negative ion source

DOEpatents

Leung, Ka-Ngo; Ehlers, Kenneth W.

1984-01-01

An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

Negative ion source

DOEpatents

Leung, K.N.; Ehlers, K.W.

1982-08-06

An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

Negative ion source

DOEpatents

Leung, K.N.; Ehlers, K.W.

1984-12-04

An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field. 14 figs.

APPARATUS FOR PRODUCING IONS OF VAPORIZABLE MATERIALS

DOEpatents

Starr, C.

1957-11-19

This patent relates to electronic discharge devices used as ion sources, and in particular describes an ion source for application in a calutron. The source utilizes two cathodes disposed at opposite ends of a longitudinal opening in an arc block fed with vaporized material. A magnetic field is provided parallel to the length of the arc block opening. The electrons from the cathodes are directed through slits in collimating electrodes into the arc block parallel to the magnetic field and cause an arc discharge to occur between the cathodes, as the arc block and collimating electrodes are at a positive potential with respect to the cathode. The ions are withdrawn by suitable electrodes disposed opposite the arc block opening. When such an ion source is used in a calutron, an arc discharge of increased length may be utilized, thereby increasing the efficiency and economy of operation.

CALUTRON

DOEpatents

Kamen, M.D.

1958-02-25

This patent describes an improved ion source for a calutron which is designed to eliminate the necessity of opening the evacuated calutron tank to permit entrance into the tank to place a further charge in thc ion source. The improved ion source comprises a charge reservoir positioned exerior to the calutron tank and connected to an ionizing device located within the tank by a channeled member. A section cf the tank wall supports the ion source structure and Is removable to allow withdrawal of the composite assembly. Heat is applied to the charge reservoir to vaporize the charge and force the charge to the ionizing device, and heat is also furnished along the connecting channel to prevent condensation of the vapor, a valve structure at the exit from the charge reservoir controls the amount of charge received by the ionizing device.

METHOD OF PRODUCING AND ACCELERATING AN ION BEAM

NASA Technical Reports Server (NTRS)

Foster, John E. (Inventor)

2005-01-01

A method of producing and accelerating an ion beam comprising the steps of providing a magnetic field with a cusp that opens in an outward direction along a centerline that passes through a vertex of the cusp: providing an ionizing gas that sprays outward through at least one capillary-like orifice in a plenum that is positioned such that the orifice is on the centerline in the cusp, outward of the vortex of the cusp; providing a cathode electron source, and positioning it outward of the orifice and off of the centerline; and positively charging the plenum relative to the cathode electron source such that the plenum functions as m anode. A hot filament may be used as the cathode electron source, and permanent magnets may be used to provide the magnetic field.

Radiocarbon measurements of small gaseous samples at CologneAMS

NASA Astrophysics Data System (ADS)

Stolz, A.; Dewald, A.; Altenkirch, R.; Herb, S.; Heinze, S.; Schiffer, M.; Feuerstein, C.; Müller-Gatermann, C.; Wotte, A.; Rethemeyer, J.; Dunai, T.

2017-09-01

A second SO-110 B (Arnold et al., 2010) ion source was installed at the 6 MV CologneAMS for the measurement of gaseous samples. For the gas supply a dedicated device from Ionplus AG was connected to the ion source. Special effort was devoted to determine optimized operation parameters for the ion source, which give a high carbon current output and a high 14C- yield. The latter is essential in cases when only small samples are available. Additionally a modified immersion lens and modified target pieces were tested and the target position was optimized.

Structural characterization of phospholipids by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry.

PubMed

Marto, J A; White, F M; Seldomridge, S; Marshall, A G

1995-11-01

Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry provides for structural analysis of the principal biological phospholipids: glycerophosphatidylcholine, -ethanolamine, -serine, and -inositol. Both positive and negative molecular or quasimolecular ions are generated in high abundance. Isolated molecular ions may be collisionally activated in the source side of a dual trap mass analyzer, yielding fragments serving to identify the polar head group (positive ion mode) and fatty acid side chains (negative ion mode). Azimuthal quadrupolar excitation following collisionally activated dissociation refocuses productions close to the solenoid axis; subsequent transfer of product ions to the analyzer ion trap allows for high-resolution mass analysis. Cyro-cooling of the sample probe with liquid nitrogen greatly reduces matrix adduction encountered in the negative ion mode.

Planned Experiments on the Princeton Advanced Test Stand

NASA Astrophysics Data System (ADS)

Stepanov, A.; Gilson, E. P.; Grisham, L.; Kaganovich, I.; Davidson, R. C.

2010-11-01

The Princeton Advanced Test Stand (PATS) device is an experimental facility based on the STS-100 high voltage test stand transferred from LBNL. It consists of a multicusp RF ion source, a pulsed extraction system capable of forming high-perveance 100keV ion beams, and a large six-foot-long vacuum with convenient access for beam diagnostics. This results in a flexible system for studying high perveance ion beams relevant to NDCX-I/II, including experiments on beam neutralization by ferroelectric plasma sources (FEPS) being developed at PPPL. Research on PATS will concern the basic physics of beam-plasma interactions, such as the effects of volume neutralization on beam emittance, as well as optimizing technology of the FEPS. PATS combines the advantage of an ion beam source and a large-volume plasma source in a chamber with ample access for diagnostics, resulting in a robust setup for investigating and improving relevant aspects of neutralized drift. There are also plans for running the ion source with strongly electro-negative gases such as chlorine, making it possible to extract positive or negative ion beams.

Porcelain-coated antenna for radio-frequency driven plasma source

DOEpatents

Leung, Ka-Ngo; Wells, Russell P.; Craven, Glen E.

1996-01-01

A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ion because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile.

Modulation instability and dissipative rogue waves in ion-beam plasma: Roles of ionization, recombination, and electron attachment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Shimin, E-mail: gsm861@126.com; Mei, Liquan, E-mail: lqmei@mail.xjtu.edu.cn

The amplitude modulation of ion-acoustic waves is investigated in an unmagnetized plasma containing positive ions, negative ions, and electrons obeying a kappa-type distribution that is penetrated by a positive ion beam. By considering dissipative mechanisms, including ionization, negative-positive ion recombination, and electron attachment, we introduce a comprehensive model for the plasma with the effects of sources and sinks. Via reductive perturbation theory, the modified nonlinear Schrödinger equation with a dissipative term is derived to govern the dynamics of the modulated waves. The effect of the plasma parameters on the modulation instability criterion for the modified nonlinear Schrödinger equation is numericallymore » investigated in detail. Within the unstable region, first- and second-order dissipative ion-acoustic rogue waves are present. The effect of the plasma parameters on the characteristics of the dissipative rogue waves is also discussed.« less

Ion source based on the cathodic arc

DOEpatents

Sanders, D.M.; Falabella, S.

1994-02-01

A cylindrically symmetric arc source to produce a ring of ions which leave the surface of the arc target radially and are reflected by electrostatic fields present in the source to a point of use, such as a part to be coated, is described. An array of electrically isolated rings positioned in the source serves the dual purpose of minimizing bouncing of macroparticles and providing electrical insulation to maximize the electric field gradients within the source. The source also includes a series of baffles which function as a filtering or trapping mechanism for any macroparticles. 3 figures.

High electronegativity multi-dipolar electron cyclotron resonance plasma source for etching by negative ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stamate, E.; Draghici, M.

2012-04-15

A large area plasma source based on 12 multi-dipolar ECR plasma cells arranged in a 3 x 4 matrix configuration was built and optimized for silicon etching by negative ions. The density ratio of negative ions to electrons has exceeded 300 in Ar/SF{sub 6} gas mixture when a magnetic filter was used to reduce the electron temperature to about 1.2 eV. Mass spectrometry and electrostatic probe were used for plasma diagnostics. The new source is free of density jumps and instabilities and shows a very good stability for plasma potential, and the dominant negative ion species is F{sup -}. Themore » magnetic field in plasma volume is negligible and there is no contamination by filaments. The etching rate by negative ions measured in Ar/SF{sub 6}/O{sub 2} mixtures was almost similar with that by positive ions reaching 700 nm/min.« less

Ion photon emission microscope

DOEpatents

Doyle, Barney L.

2003-04-22

An ion beam analysis system that creates microscopic multidimensional image maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the ion-induced photons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted photons are collected in the lens system of a conventional optical microscope, and projected on the image plane of a high resolution single photon position sensitive detector. Position signals from this photon detector are then correlated in time with electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these photons initially.

Photosensitivity enhancement of PLZT ceramics by positive ion implantation

DOEpatents

Land, Cecil E.; Peercy, Paul S.

1983-01-01

The photosensitivity of lead lanthanum zirconate titanate (PLZT) ceramic material used in high resolution, high contrast, and non-volatile photoferroelectric image storage and display devices is enhanced significantly by positive ion implantation of the PLZT near its surface. Implanted ions include H.sup.+, He.sup.+, Ne.sup.+, Ar.sup.+, as well as chemically reactive ions from Fe, Cr, and Al. The positive ion implantation advantageously serves to shift the absorption characteristics of the PLZT material from near-UV light to visible light. As a result, photosensitivity enhancement is such that the positive ion implanted PLZT plate is sensitive even to sunlight and conventional room lighting, such as fluorescent and incandescent light sources. The method disclosed includes exposing the PLZT plate to the positive ions at sufficient density, from 1.times.10.sup.12 to 1.times.10.sup.17, and with sufficient energy, from 100 to 500 KeV, to provide photosensitivity enhancement. The PLZT material may have a lanthanum content ranging from 5 to 10%, a lead zirconate content of 62 to 70 mole %, and a lead titanate content of 38 to 30%. The ions are implanted at a depth of 0.1 to 2 microns below the surface of the PLZT plate.

Ion focusing

DOEpatents

Cooks, Robert Graham; Baird, Zane; Peng, Wen-Ping

2015-11-10

The invention generally relates to apparatuses for focusing ions at or above ambient pressure and methods of use thereof. In certain embodiments, the invention provides an apparatus for focusing ions that includes an electrode having a cavity, at least one inlet within the electrode configured to operatively couple with an ionization source, such that discharge generated by the ionization source is injected into the cavity of the electrode, and an outlet. The cavity in the electrode is shaped such that upon application of voltage to the electrode, ions within the cavity are focused and directed to the outlet, which is positioned such that a proximal end of the outlet receives the focused ions and a distal end of the outlet is open to ambient pressure.

Ion focusing

DOEpatents

Cooks, Robert Graham; Baird, Zane; Peng, Wen-Ping

2017-01-17

The invention generally relates to apparatuses for focusing ions at or above ambient pressure and methods of use thereof. In certain embodiments, the invention provides an apparatus for focusing ions that includes an electrode having a cavity, at least one inlet within the electrode configured to operatively couple with an ionization source, such that discharge generated by the ionization source is injected into the cavity of the electrode, and an outlet. The cavity in the electrode is shaped such that upon application of voltage to the electrode, ions within the cavity are focused and directed to the outlet, which is positioned such that a proximal end of the outlet receives the focused ions and a distal end of the outlet is open to ambient pressure.

Porcelain-coated antenna for radio-frequency driven plasma source

DOEpatents

Leung, K.N.; Wells, R.P.; Craven, G.E.

1996-12-24

A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ions because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile. 8 figs.

Ion-induced electron emission microscopy

DOEpatents

Doyle, Barney L.; Vizkelethy, Gyorgy; Weller, Robert A.

2001-01-01

An ion beam analysis system that creates multidimensional maps of the effects of high energy ions from an unfocussed source upon a sample by correlating the exact entry point of an ion into a sample by projection imaging of the secondary electrons emitted at that point with a signal from a detector that measures the interaction of that ion within the sample. The emitted secondary electrons are collected in a strong electric field perpendicular to the sample surface and (optionally) projected and refocused by the electron lenses found in a photon emission electron microscope, amplified by microchannel plates and then their exact position is sensed by a very sensitive X Y position detector. Position signals from this secondary electron detector are then correlated in time with nuclear, atomic or electrical effects, including the malfunction of digital circuits, detected within the sample that were caused by the individual ion that created these secondary electrons in the fit place.

Characteristics of a RF-Driven Ion Source for a Neutron Generator Used for Associated Particle Imaging

NASA Astrophysics Data System (ADS)

Wu, Ying; Hurley, John P.; Ji, Qing; Kwan, Joe; Leung, Ka-Ngo

2009-03-01

We present recent work on a prototype compact neutron generator for associated particle imaging (API). API uses alpha particles that are produced simultaneously with neutrons in the deuterium-tritium (2D(3T,n)4α) fusion reaction to determine the direction of the neutrons upon exiting the reaction. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. The ion source for API is designed to produce a focused ion beam with a beam spot diameter of 1-mm or less on the target. We use an axial type neutron generator with a predicted neutron yield of 108 n/s for a 50 μA D/T ion beam current accelerated to 80 kV. The generator utilizes an RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of over 80% can be obtained while utilizing only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the tube. Experimental results from ion source testing, such as the current density, atomic ion fraction, electron temperature, and electron density will be discussed.

Modification of anti-bacterial surface properties of textile polymers by vacuum arc ion source implantation

NASA Astrophysics Data System (ADS)

Nikolaev, A. G.; Yushkov, G. Yu.; Oks, E. M.; Oztarhan, A.; Akpek, A.; Hames-Kocabas, E.; Urkac, E. S.; Brown, I. G.

2014-08-01

Ion implantation provides an important technology for the modification of material surface properties. The vacuum arc ion source is a unique instrument for the generation of intense beams of metal ions as well as gaseous ions, including mixed metal-gas beams with controllable metal:gas ion ratio. Here we describe our exploratory work on the application of vacuum arc ion source-generated ion beams for ion implantation into polymer textile materials for modification of their biological cell compatibility surface properties. We have investigated two specific aspects of cell compatibility: (i) enhancement of the antibacterial characteristics (we chose to use Staphylococcus aureus bacteria) of ion implanted polymer textile fabric, and (ii) the "inverse" concern of enhancement of neural cell growth rate (we chose Rat B-35 neuroblastoma cells) on ion implanted polymer textile. The results of both investigations were positive, with implantation-generated antibacterial efficiency factor up to about 90%, fully comparable to alternative conventional (non-implantation) approaches and with some potentially important advantages over the conventional approach; and with enhancement of neural cell growth rate of up to a factor of 3.5 when grown on suitably implanted polymer textile material.

Fast neutral beam ion source coupled to a Fourier transform ion cyclotron resonance mass spectrometer

NASA Astrophysics Data System (ADS)

Hill, Nicholas C.; Limbach, Patrick A.; Shomo, Ronald E., II; Marshall, Alan G.; Appelhans, Anthony D.; Delmore, James E.

1991-11-01

The coupling of an autoneutralizing SF-6 fast ion-beam gun to a Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometer is described. The fast neutral beam provides for secondary-ion-type FT/ICR mass analysis [e.g., production of abundant pseudomolecular (M+H)+ ions] of involatile samples without the need for external ion injection, since ions are formed at the entrance to the ICR ion trap. The design, construction, and testing of the hybrid instrument are described. The feasibility of the experiment (for both broadband and high-resolution FT/ICR positive-ion mass spectra) is demonstrated with tetra-butylammonium bromide and a Tylenol■ sample. The ability to analyze high molecular weight polymers with high mass resolution is demonstrated for Teflon■. All of the advantages of the fast neutral beam ion source previously demonstrated with quadrupole mass analysis are preserved, and the additional advantages of FT/ICR mass analysis (e.g., high mass resolving power, ion trapping) are retained.

The influence of ambipolarity on plasma confinement and on the performance of electron cyclotron resonance ion sources.

PubMed

Schachter, L; Dobrescu, S; Stiebing, K E; Thuillier, T; Lamy, T

2008-02-01

Charge diffusion in an electron cyclotron resonance ion source (ECRIS) discharge is usually characterized by nonambipolar behavior. While the ions are transported to the radial walls, electrons are lost axially from the magnetic trap. Global neutrality is maintained via compensating currents in the conducting walls of the vacuum chamber. It is assumed that this behavior reduces the ion breeding times compared to a truly ambipolar plasma. We have carried out a series of dedicated experiments in which the ambipolarity of the ECRIS plasma was influenced by inserting special metal-dielectric structures (MD layers) into the plasma chamber of the Frankfurt 14 GHz ECRIS. The measurements demonstrate the positive influence on the source performance when the ECR plasma is changed toward more ambipolar behavior.

Multi-source ion funnel

DOEpatents

Tang, Keqi; Belov, Mikhail B.; Tolmachev, Aleksey V.; Udseth, Harold R.; Smith, Richard D.

2005-12-27

A method for introducing ions generated in a region of relatively high pressure into a region of relatively low pressure by providing at least two electrospray ion sources, providing at least two capillary inlets configured to direct ions generated by the electrospray sources into and through each of the capillary inlets, providing at least two sets of primary elements having apertures, each set of elements having a receiving end and an emitting end, the primary sets of elements configured to receive a ions from the capillary inlets at the receiving ends, and providing a secondary set of elements having apertures having a receiving end and an emitting end, the secondary set of elements configured to receive said ions from the emitting end of the primary sets of elements and emit said ions from said emitting end of the secondary set of elements. The method may further include the step of providing at least one jet disturber positioned within at least one of the sets of primary elements, providing a voltage, such as a dc voltage, in the jet disturber, thereby adjusting the transmission of ions through at least one of the sets of primary elements.

Measurement of ion species in high current ECR H⁺/D⁺ ion source for IFMIF (International Fusion Materials Irradiation Facility).

PubMed

Shinto, K; Senée, F; Ayala, J-M; Bolzon, B; Chauvin, N; Gobin, R; Ichimiya, R; Ihara, A; Ikeda, Y; Kasugai, A; Kitano, T; Kondo, K; Marqueta, A; Okumura, Y; Takahashi, H; Valette, M

2016-02-01

Ion species ratio of high current positive hydrogen/deuterium ion beams extracted from an electron-cyclotron-resonance ion source for International Fusion Materials Irradiation Facility accelerator was measured by the Doppler shift Balmer-α line spectroscopy. The proton (H(+)) ratio at the middle of the low energy beam transport reached 80% at the hydrogen ion beam extraction of 100 keV/160 mA and the deuteron (D(+)) ratio reached 75% at the deuterium ion beam extraction of 100 keV/113 mA. It is found that the H(+) ratio measured by the spectroscopy gives lower than that derived from the phase-space diagram measured by an Allison scanner type emittance monitor. The H(+)/D(+) ratio estimated by the emittance monitor was more than 90% at those extraction currents.

A tandem mass spectrometer for crossed-beam irradiation of mass-selected molecular systems by keV atomic ions

NASA Astrophysics Data System (ADS)

Schwob, Lucas; Lalande, Mathieu; Chesnel, Jean-Yves; Domaracka, Alicja; Huber, Bernd A.; Maclot, Sylvain; Poully, Jean-Christophe; Rangama, Jimmy; Rousseau, Patrick; Vizcaino, Violaine; Adoui, Lamri; Méry, Alain

2018-04-01

In the present paper, we describe a new home-built crossed-beam apparatus devoted to ion-induced ionization and fragmentation of isolated biologically relevant molecular systems. The biomolecular ions are produced by an electrospray ionization source, mass-over-charge selected, accumulated in a 3D ion trap, and then guided to the extraction region of an orthogonal time-of-flight mass spectrometer. Here, the target molecular ions interact with a keV atomic ion beam produced by an electron cyclotron resonance ion source. Cationic products from the collision are detected on a position sensitive detector and analyzed by time-of-flight mass spectrometry. A detailed description of the operation of the setup is given, and early results from irradiation of a protonated pentapeptide (leucine-enkephalin) by a 7 keV He+ ion beam are presented as a proof-of-principle.

Multi-Frequency Microwaves Plasma Production for Active Profile Control of Ion Beams on a Large Bore ECR Ion Source with Permanent Magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakamoto, Naoki; Kato, Yushi; Kiriyama, Ryutaro

2011-01-07

A new concept on magnetic field of plasma production and confinement by using permanent magnets, i.e. cylindrically comb-shaped magnets, has been proposed to enhance efficiency of an electron cyclotron resonance (ECR) plasma for broad and dense ion beam source under the low pressure and also the low microwave power. The resonance zones corresponding to the fundamental ECR for 2.45 GHz and 11-13 GHz frequency are constructed at different positions. The profiles of the plasma parameters in the ECR ion source are different from each frequency of microwave. Large bore extractor is set at the opposite side against the microwave feeds.more » It is found that differences of their profiles also appear at those of ion beam profiles. We conducted to launch simultaneously multiplex frequency microwaves controlled individually, and tried to control the profiles of the plasma parameters and then those of extracted ion beam.« less

Cluster secondary ion mass spectrometry microscope mode mass spectrometry imaging.

PubMed

Kiss, András; Smith, Donald F; Jungmann, Julia H; Heeren, Ron M A

2013-12-30

Microscope mode imaging for secondary ion mass spectrometry is a technique with the promise of simultaneous high spatial resolution and high-speed imaging of biomolecules from complex surfaces. Technological developments such as new position-sensitive detectors, in combination with polyatomic primary ion sources, are required to exploit the full potential of microscope mode mass spectrometry imaging, i.e. to efficiently push the limits of ultra-high spatial resolution, sample throughput and sensitivity. In this work, a C60 primary source was combined with a commercial mass microscope for microscope mode secondary ion mass spectrometry imaging. The detector setup is a pixelated detector from the Medipix/Timepix family with high-voltage post-acceleration capabilities. The system's mass spectral and imaging performance is tested with various benchmark samples and thin tissue sections. The high secondary ion yield (with respect to 'traditional' monatomic primary ion sources) of the C60 primary ion source and the increased sensitivity of the high voltage detector setup improve microscope mode secondary ion mass spectrometry imaging. The analysis time and the signal-to-noise ratio are improved compared with other microscope mode imaging systems, all at high spatial resolution. We have demonstrated the unique capabilities of a C60 ion microscope with a Timepix detector for high spatial resolution microscope mode secondary ion mass spectrometry imaging. Copyright © 2013 John Wiley & Sons, Ltd.

Enhancement of SPES source performances.

PubMed

Fagotti, E; Palmieri, A; Ren, X

2008-02-01

Installation of SPES source at LNL was finished in July 2006 and the first beam was extracted in September 2006. Commissioning results confirmed very good performance of the extracted current density. Conversely, source reliability was very poor due to glow-discharge phenomena, which were caused by the ion source axial magnetic field protruding in the high-voltage column. This problem was fixed by changing the stainless steel plasma electrode support with a ferromagnetic one. This new configuration required us to recalculate ion source solenoids positions and fields in order to recover the correct resonance pattern. Details on magnetic simulations and experimental results of high voltage column shielding are presented.

Photosensitivity enhancement of PLZT ceramics by positive ion implantation

DOEpatents

Peercy, P.S.; Land, C.E.

1980-06-13

The photosensitivity of lead lanthanum zirconate titanate (PLZT) ceramic material used in high resolution, high contrast, and non-volatile photoferroelectric image storage and display devices is enhanced significantly by positive ion implantation of the PLZT near its surface. Ions that are implanted include H/sup +/, He/sup +/, Ar/sup +/, and a preferred co-implant of Ar/sup +/ and Ne/sup +/. The positive ion implantation advantageously serves to shift the band gap energy threshold of the PLZT material from near-uv light to visible blue light. As a result, photosensitivity enhancement is such that the positive ion implanted PLZT plate is sensitive even to sunlight and conventional room lighting, such as fluorescent and incandescent light sources. The method disclosed includes exposing the PLZT plate to these positive ions of sufficient density and with sufficient energy to provide an image. The PLZT material may have a lanthanum content ranging from 5 to 10%; a lead zirconate content ranging from 62 to 70 mole %; and a lead titanate content ranging from 38 to 30%. The region of ion implantation is in a range from 0.1 to 2 microns below the surface of the PLZT plate. Density of ions is in the range from 1 x 10/sup 12/ to 1 x 10/sup 17/ ions/cm/sup 2/ and having an energy in the range from 100 to 500 keV.

DOE Office of Scientific and Technical Information (OSTI.GOV)

St Lishev, Stiliyan; Shivarova, Antonia P.

The study combines experiments on probe diagnostics with laser-photodetachment-technique and Faraday-cup measurements directed towards determination of the position of the extraction device and its influence on the discharge structure. The measurements have been carried out in the second chamber of an inductively-driven tandem plasma source performed as small scale arrangements, with a magnetic filter located just after the transition between the two chambers of the source. Results for the axial profiles of the plasma parameters display the correlation of the ratio n lowbar /n{sub e} of the densities of the negative hydrogen ions and of the electrons and of themore » concentration of the negative ions with the electron density and temperature: The maxima of the (n lowbar /n{sub e})-ratio and of the density of the negative ions obtained are located at the position of maximum of the electron density behind the filter, in the region of the low electron temperature. Results from probe diagnostics and laser photodetachment measurements at a given axial position for different positions of the Faraday cup show the changes in the spatial distribution of the electron density and temperature and the reduction of the (n lowbar /n{sub e})-ratio and of the density of the negative ions caused by the extraction device.« less

Investigation of the ion beam emission from a pulsed power plasma device

NASA Astrophysics Data System (ADS)

Henríquez, A.; Bhuyan, H.; Favre, M.; Retamal, M. J.; Volkmann, U.; Wyndham, E.; Chuaqui, H.

2014-05-01

Plasma Focus (PF) devices are well known as ion beam sources with characteristic energy among the hundreds of keV to tens of MeV. The information on ion beam energy, ion distribution and composition is essential from the viewpoint of understanding fundamental physics behind their production and acceleration and also their applications in various fields, such as surface properties modification, ion implantation, thin film deposition, semiconductor doping and ion assisted coating. An investigation from a low energy, 1.8 kJ 160 kA, Mather type plasma focus device operating with nitrogen using CR-39 detectors was conducted to study the emission of ions at different angular positions. Tracks on CR-39 detectors at different angular positions reveal the existence of angular ion anisotropy. The results obtained are comparable with the time integrated measurements using FC. Preliminary results of this work are presented.

APPARATUS FOR CONTROLLING THE POSITION OF AN ION BEAM IN A CALUTRON

DOEpatents

Lawrence, E.O.

1958-01-01

ABS>This patent relates to improvements in electric discharge devices of the calutron type for separation of the isotopes of an element from the freely occurring composition. The improvement constitutes means for the continuous control of the path of an ion beam to obtain maximum reception in a receiver compartment. Withdrawal of the ions from the source is accomplished by an accelerator electrode placed at a positive potential with respect to the receiver. The ions are projected through a magnetic field perpendicular to the direction of motion towards a receiver. In order to obtain a signal representative of the magnitude of ions received from a particular ion-beam in its compartment, an electrode is disposed in the compartment. The signal from the compartment electrode controls the voltage of the acccleratimg electrodc through appropriate circuitry to maintain the path of the particular ion beam optimum for maximum ion current in the compartment.

Ball lightning dynamics and stability at moderate ion densities

NASA Astrophysics Data System (ADS)

Morrow, R.

2017-10-01

A general mechanism is presented for the dynamics and structure of ball lightning and for the maintenance of the ball lightning structure for several seconds. Results are obtained using a spherical geometry for air at atmospheric pressure, by solving the continuity equations for electrons, positive ions and negative ions coupled with Poisson’s equation. A lightning strike can generate conditions in the lightning channel with a majority of positive nitrogen ions, and a minority of negative oxygen ions and electrons. The calculations are initiated with electrons included; however, at the moderate ion densities chosen the electrons are rapidly lost to form negative ions, and after 1 µs their influence on the ion dynamics is negligible. Further development after 1 µs is followed using a simpler set of equations involving only positive ions and negative ions, but including ion diffusion. The space-charge electric field generated by the majority positive ions drives them from the centre of the distribution and drives the minority negative ions and electrons towards the centre of the distribution. In the central region the positive and negative ion distributions eventually overlap exactly and their space-charge fields cancel resulting in zero electric field, and the plasma ball formed is quite stable for a number of seconds. The formation of such plasma balls is not critically dependent on the initial diameter of the ion distributions, or the initial density of minority negative ions. The ion densities decrease relatively slowly due to mutual neutralization of positive and negative ions. The radiation from this neutralization process involving positive nitrogen ions and negative oxygen ions is not sufficient to account for the reported luminosity of ball lightning and some other source of luminosity is shown to be required; the plasma ball model used could readily incorporate other ions in order to account for the luminosity and range of colours reported for ball lightning. Additionally, ‘phantom plasma balls’ may well be generated and go unnoticed due to very low luminosity; luminous ball lightning may be the exception. Finally, the mechanism described here may also be active in the dynamics of bead lightning.

Heavy haze episodes in Beijing during January 2013: Inorganic ion chemistry and source analysis using highly time-resolved measurements from an urban site.

PubMed

Han, Bin; Zhang, Rui; Yang, Wen; Bai, Zhipeng; Ma, Zhiqiang; Zhang, Wenjie

2016-02-15

The heavy air pollution that occurred in Beijing in January of 2013 attracted intense attention around the world. During this period, we conducted highly time-resolved measurements of inorganic ions associated with PM2.5 at an urban site of Beijing, and investigated ion chemistry and potential sources. Hourly concentrations of Cl(-), NO3(-), SO4(2-), Na(+), NH4(+), K(+), Mg(2+), and Ca(2+) were measured. Peak concentrations of SO4(2-) and NO3(-) were observed on the 10th-15th, 21st-24th, and the 26th-30th during this monitoring campaign. The percentages of SO4(2-) and NH4(+) in total ion concentration increased with the enhancement of PM2.5 concentrations, indicating that high concentrations of SO4(2-) and NH4(+) may play important roles in the formation of haze episodes. The ratio of [NO3(-)]/[SO4(2-)] was calculated, revealing that the sources of SO4(2-) would contribute more to the formation of PM2.5 than mobile sources. Diurnal variations of SO4(2-), NO3(-), NH4(+) (SNA) exhibited a similar pattern, with high concentrations at night and low levels during the day, revealing that meteorological conditions, such as mixing layer height, relative humidity, were likely to be responsible for high levels of SNA at night. The roles of meteorological conditions were further discussed in the formation of secondary inorganic ions. Relative humidity and temperature played key roles and exhibited positive correlations with secondary inorganic ions. An aerosol inorganics simulation model showed that SNA existed mainly in the aqueous phase during the sampling period. Furthermore, potential sources were identified by applying positive matrix factorization model. Secondary nitrate, secondary sulfate, coal combustion and biomass burning, as well as fugitive dust, were considered to be major contributors to total ions. Copyright © 2015. Published by Elsevier B.V.

CALUTRON ION SOURCE

DOEpatents

Oppenheimer, F.

1958-08-19

The construction of an ion source is descrtbed wherein a uniform and elongated arc is established for employment in a calutron. The novel features of the . source include the positioning of a cathode at one end of an elongated extt slit of an arc chamber. and anode electrodes defintng the longitudinal margins of the exit opening. When the exit slit is orientated in a parallel relation to a magnetic field, the arc extends in the direction of the magnetic field along and between the anode electrodes, which are held at a positsve potential with respect to the cathode.

Air ion exposure system for plants

NASA Technical Reports Server (NTRS)

Morrow, R. C.; Tibbitts, T. W.

1987-01-01

A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.

Air ion exposure system for plants.

PubMed

Morrow, R C; Tibbitts, T W

1987-02-01

A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.

A review of ion sources for medical accelerators (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muramatsu, M.; Kitagawa, A.

2012-02-15

There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespreadmore » since the 1990s. The energy and intensity are typically over 200 MeV and several 10{sup 10} pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV/u. Although the beam intensity depends on the irradiation method, it is typically several 10{sup 8} or 10{sup 9} pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of accelerators are under development for the boron neutron capture therapy. This treatment is conventionally demonstrated by a nuclear reactor, but it is strongly expected to replace the reactor by the accelerator. We report status of ion source for medical application and such scope for further developments.« less

An External Matrix-Assisted Laser Desorption Ionization Source for Flexible FT-ICR Mass Spectrometry Imaging with Internal Calibration on Adjacent Samples

NASA Astrophysics Data System (ADS)

Smith, Donald F.; Aizikov, Konstantin; Duursma, Marc C.; Giskes, Frans; Spaanderman, Dirk-Jan; McDonnell, Liam A.; O'Connor, Peter B.; Heeren, Ron M. A.

2011-01-01

We describe the construction and application of a new MALDI source for FT-ICR mass spectrometry imaging. The source includes a translational X-Y positioning stage with a 10 × 10 cm range of motion for analysis of large sample areas, a quadrupole for mass selection, and an external octopole ion trap with electrodes for the application of an axial potential gradient for controlled ion ejection. An off-line LC MALDI MS/MS run demonstrates the utility of the new source for data- and position-dependent experiments. A FT-ICR MS imaging experiment of a coronal rat brain section yields ˜200 unique peaks from m/z 400-1100 with corresponding mass-selected images. Mass spectra from every pixel are internally calibrated with respect to polymer calibrants collected from an adjacent slide.

Alternative mass reference standards for direct analysis in real time mass spectrometry.

PubMed

Cody, Robert B; Dane, A John

2016-05-30

Mass spectra were acquired with the Direct Analysis in Real Time (DART®) ion source for an amine-terminated polyether used as positive-ion mass reference standards and for several fluorinated materials commonly used as negative-ion reference standards for mass spectrometry. A commercial time-of-flight mass spectrometer equipped with a DART ion source was used for all measurements. Mass reference standards deposited onto the sealed end of a glass melting point tube were suspended in the DART gas stream for analysis. A polyetheramine (Jeffamine® M-600) produced intense peaks corresponding to protonated molecules. Perfluorotributylamine (PFTBA), and perfluorotripentylamine, gave useful reference spectra for different m/z ranges. DART mass spectra of Ultramark 1621® resembled those previously reported for Fast Atom Bombardment (FAB) and Electrospray Ionization (ESI). Fomblin®Y, a fluorinated ether, was the most useful negative-ion reference standard of the materials tested. The material is commercially available, inexpensive, and provides reference peaks covering the m/z range 85 to >3000. Jeffamine-M600 was found to be a convenient alternative to polyethers such as polyethylene glycol (PEG) for DART positive-ion mass calibration. Fomblin Y was suitable for use as a negative-ion reference standard. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Monte Carlo study on secondary neutrons in passive carbon-ion radiotherapy: identification of the main source and reduction in the secondary neutron dose.

PubMed

Yonai, Shunsuke; Matsufuji, Naruhiro; Kanai, Tatsuaki

2009-10-01

Recent successful results in passive carbon-ion radiotherapy allow the patient to live for a longer time and allow younger patients to receive the radiotherapy. Undesired radiation exposure in normal tissues far from the target volume is considerably lower than that close to the treatment target, but it is considered to be non-negligible in the estimation of the secondary cancer risk. Therefore, it is very important to reduce the undesired secondary neutron exposure in passive carbon-ion radiotherapy without influencing the clinical beam. In this study, the source components in which the secondary neutrons are produced during passive carbon-ion radiotherapy were identified and the method to reduce the secondary neutron dose effectively based on the identification of the main sources without influencing the clinical beam was investigated. A Monte Carlo study with the PHITS code was performed by assuming the beamline at the Heavy-Ion Medical Accelerator in Chiba (HIMAC). At first, the authors investigated the main sources of secondary neutrons in passive carbon-ion radiotherapy. Next, they investigated the reduction in the neutron dose with various modifications of the beamline device that is the most dominant in the neutron production. Finally, they investigated the use of an additional shield for the patient. It was shown that the main source is the secondary neutrons produced in the four-leaf collimator (FLC) used as a precollimator at HIAMC, of which contribution in the total neutron ambient dose equivalent is more than 70%. The investigations showed that the modification of the FLC can reduce the neutron dose at positions close to the beam axis by 70% and the FLC is very useful not only for the collimation of the primary beam but also the reduction in the secondary neutrons. Also, an additional shield for the patient is very effective to reduce the neutron dose at positions farther than 50 cm from the beam axis. Finally, they showed that the neutron dose can be reduced by approximately 70% at any position without influencing the primary beam used in treatment. This study was performed by assuming the HIMAC beamline; however, this study provides important information for reoptimizing the arrangement and the materials of beamline devices and designing a new facility for passive carbon-ion radiotherapy and probably passive proton radiotherapy.

Fabrication and characterization of a 3D Positive ion detector and its applications

NASA Astrophysics Data System (ADS)

Venkatraman, Pitchaikannu; Sureka, Chandrasekaran Senbagavadivoo

2017-11-01

There is a growing interest to experimentally evaluate the track structure induced by ionizing particles in order to characterize the radiobiological quality of ionizing radiation for applications in radiotherapy and radiation protection. To do so, a novel positive ion detector based on the multilayer printed circuit board (PCB) technology has been proposed previously, which works under the principle of ion induced impact ionization. Based on this, an upgraded 3D positive ion detector was fabricated in order to improve its efficiency and use it for various applications. To improve the efficiency of the detector, cathodes with different insulators (Bakelite plate and Steatite Ceramics) and conducting layers (ITO, FTO, and Gold coated cathode) were studied under various gaseous media (methane, nitrogen, and air) using Am-241, Co-60, Co-57, Na-22, Cs-137, and Ba-133 sources. From this study, it is confirmed that the novel 3D positive ion detector that has been upgraded using gold as strip material, tungsten (87%) coated copper (13%) as the core wire, gold coated ceramic as cathode, and thickness of 3.483 mm showed 9.2% efficiency under methane medium at 0.9 Torr pressure using an Am-241 source. It is also confirmed that when the conductivity of the cathode and thickness of the detector is increased, the performance of the detector is improved significantly. Further, the scope of the detector to use in the field of radiation protection, radiation dosimetry, gamma spectrometry, radiation biology, and oncology are reported here.

Wall-loss distribution of charge breeding ions in an electron cyclotron resonance ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, S. C.; Oyaizu, M.; Imai, N.

2011-03-15

The ion loss distribution in an electron cyclotron resonance ion source (ECRIS) was investigated to understand the element dependence of the charge breeding efficiency in an electron cyclotron resonance (ECR) charge breeder. The radioactive {sup 111}In{sup 1+} and {sup 140}Xe{sup 1+} ions (typical nonvolatile and volatile elements, respectively) were injected into the ECR charge breeder at the Tokai Radioactive Ion Accelerator Complex to breed their charge states. Their respective residual activities on the sidewall of the cylindrical plasma chamber of the source were measured after charge breeding as functions of the azimuthal angle and longitudinal position and two-dimensional distributions ofmore » ions lost during charge breeding in the ECRIS were obtained. These distributions had different azimuthal symmetries. The origins of these different azimuthal symmetries are qualitatively discussed by analyzing the differences and similarities in the observed wall-loss patterns. The implications for improving the charge breeding efficiencies of nonvolatile elements in ECR charge breeders are described. The similarities represent universal ion loss characteristics in an ECR charge breeder, which are different from the loss patterns of electrons on the ECRIS wall.« less

Physics-based investigation of negative ion behavior in a negative-ion-rich plasma using integrated diagnostics

NASA Astrophysics Data System (ADS)

Tsumori, K.; Takeiri, Y.; Ikeda, K.; Nakano, H.; Geng, S.; Kisaki, M.; Nagaoka, K.; Tokuzawa, T.; Wada, M.; Sasaki, K.; Nishiyama, S.; Goto, M.; Osakabe, M.

2017-08-01

Total power of 16 MW has been successfully delivered to the plasma confined in the Large Helical Device (LHD) from three Neutral Beam Injectors (NBIs) equipped with negative hydrogen (H-) ion sources. However, the detailed mechanisms from production through extraction of H- ions are still yet to be clarified and a similar size ion source on an independent acceleration test bench called Research and development Negative Ion Source (RNIS) serves as the facility to study physics related to H- production and transport for further improvement of NBI. The production of negative-ion-rich plasma and the H- ions behavior in the beam extraction region in RNIS is being investigated by employing an integrated diagnostic system. Flow patterns of electrons, positive ions and H- ions in the extraction region are described in a two-dimensional map. The measured flow patterns indicate the existence a stagnation region, where the H- flow changes the direction at a distance about 20 mm from the plasma grid. The pattern also suggested the H- flow originated from plasma grid (PG) surface that turned back toward extraction apertures. The turning region seems formed by a layer of combined magnetic field produced by the magnetic filter field and the Electron-Deflection Magnetic (EDM) field created by magnets installed in the extraction electrode.

Design and Performance of a High-Flux Electrospray Ionization Source for Ion Soft-Landing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunaratne, Kalupathirannehelage Don D.; Prabhakaran, Venkateshkumar; Ibrahim, Yehia M.

2015-01-01

We report the design and evaluation of a new high-intensity electrospray ionization source for ion soft-landing experiments. The source incorporates a dual ion funnel, which enables operation with a higher gas load through an expanded heated inlet into the additional first region of differential pumping. This capability allowed us to examine the effect of the inner diameter (ID) of the heated stainless steel inlet on the total ion current transmitted through the dual funnel interface and, more importantly, the mass-selected ion current delivered to the deposition target. The ion transmission of the dual funnel is similar to the transmission ofmore » the single funnel used in our previous soft landing studies. However, substantially higher ion currents were obtained using larger ID heated inlets and an orthogonal inlet geometry, in which the heated inlet is positioned perpendicular to the direction of ion propagation through the instrument. The highest ion currents were obtained using the orthogonal geometry and a 1.4 mm ID heated inlet. The corresponding stable deposition rate of ~1 μg of mass-selected ions per day will facilitate future studies focused on the controlled deposition of biological molecules on substrates and preparation of materials for studies in catalysis, energy storage, and self-assembly« less

Saddle antenna radio frequency ion sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudnikov, V., E-mail: vadim@muonsinc.com; Johnson, R.; Murray, S.

Existing RF ion sources for accelerators have specific efficiencies for H{sup +} and H{sup −} ion generation ∼3–5 mA/cm{sup 2} kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) surface plasma source (SPS) described here was developed to improve H{sup −} ion production efficiency, reliability, and availability. In SA RF ion source, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm{sup 2} kW. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA withmore » RF power ∼1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ∼4 kW RF. Continuous wave (CW) operation of the SA SPS has been tested on the test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. CW operation with negative ion extraction was tested with RF power up to ∼1.2 kW in the plasma with production up to Ic = 7 mA. A stable long time generation of H{sup −} beam without degradation was demonstrated in RF discharge with AlN discharge chamber.« less

Electron energy recovery system for negative ion sources

DOEpatents

Dagenhart, William K.; Stirling, William L.

1982-01-01

An electron energy recovery system for negative ion sources is provided. The system, employs crossed electric and magnetic fields to separate the electrons from ions as they are extracted from a negative ion source plasma generator and before the ions are accelerated to their full kinetic energy. With the electric and magnetic fields oriented 90.degree. to each other, the electrons are separated from the plasma and remain at approximately the electrical potential of the generator in which they were generated. The electrons migrate from the ion beam path in a precessing motion out of the ion accelerating field region into an electron recovery region provided by a specially designed electron collector electrode. The electron collector electrode is uniformly spaced from a surface of the ion generator which is transverse to the direction of migration of the electrons and the two surfaces are contoured in a matching relationship which departs from a planar configuration to provide an electric field component in the recovery region which is parallel to the magnetic field thereby forcing the electrons to be directed into and collected by the electron collector electrode. The collector electrode is maintained at a potential slightly positive with respect to the ion generator so that the electrons are collected at a small fraction of the full accelerating supply voltage energy.

Analysis of the saturation phenomena of the neutralization rate of positively charged 218Po in water vapor.

PubMed

Tan, Yanliang; Xiao, Detao; Shan, Jian; Zhou, Qingzhi; Qu, Jingnian

2014-09-01

Generally, 88% of the freshly generated 218Po ions decayed from 222Rn are positively charged. These positive ions become neutralized by recombination with negative ions, and the main source of the negative ions is the OH- ions formed by radiolysis of water vapor. However, the neutralization rate of positively charged 218Po versus the square root of the concentration of H2O will be a constant when the concentration of H2O is sufficiently high. Since the electron affinity of the hydroxyl radical formed by water vapor is high, the authors propose that the hydroxyl radical can grab an electron to become OH-. Because the average period of collision with other positively charged ions and the average life of the OH- are much longer than those of the electron, the average concentration of negative ions will grow when the water vapor concentration increases. The authors obtained a model to describe the growth of OH- ions. From this model, it was found that the maximum value of the OH- ion concentration is limited by the square root of the radon concentration. If the radon concentration is invariant, the OH- ion concentration should be approximately a constant when the water vapor concentration is higher than a certain value. The phenomenon that the neutralization rate of positively charged 218Po versus the square root of the water vapor concentration will be saturated when the water vapor concentration is sufficiently high can be explained by this mechanism. This mechanism can be used also to explain the phenomenon that the detection efficiency of a radon monitor based on the electrostatic collection method seems to be constant when the water vapor concentration is high.

In situ measurements of the mesosphere and stratosphere

NASA Technical Reports Server (NTRS)

Crosky, C.

1976-01-01

The operation of a subsonic, Gerdien condenser probe for in situ measurements of the mesosphere and stratosphere is presented. The inclusion of a flashing Lyman alpha ultraviolet source provides an artifically produced ionization of particular constituents. Detailed theory of operation is presented and the data results from two flights are shown. A great deal of fine structure in mobility is observed due to the presence of various hydrated positive ions. The effect of the Lyman alpha source in the 35 km region was to dissociate a light hydrate ion rather than produce additional ionization. At the 70 km region, photodissociation of the heaviest ions (probably ice crystals) was also observed.

Mixed Pierce-two-stream instability development in an extraction system of a negative ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barminova, H. Y., E-mail: barminova@mephi.ru; Chikhachev, A. S.

2016-02-15

Mixed Pierce-two-stream instability may occur in an extraction system of a negative ion source based on a volume-produced plasma. The reasons for instability development are discussed. Analytically the conditions of unstable beam propagation are determined. The instability threshold is shown to be increased compared with the pure Pierce instability. The influence of inclined perturbations on the instability behavior is investigated. The numerical calculations are performed in COMSOL Multiphysics. The simulation results confirm the existence of such a mixed instability appearance that develops due to both the electrons of the external circuit and the background positive ions.

Development of the JT-60SA Neutral Beam Injectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanada, M.; Kojima, A.; Inoue, T.

2011-09-26

This paper describes the development of the neutral beam (NB) systems on JT-60SA, where 30-34 MW D{sup 0} beams are required to be injected for 100 s. A 30 s operation of the NB injectors suggests that existing beamline components and positive ion sources on JT-60U can be reused without the modifications on JT-60 SA. The JT-60 negative ion source was modified to improve the voltage holding capability, which leads to a successful acceleration of 2.8 A H{sup -} ion beam up to 500 keV of the rated acceleration energy for JT-60SA.

Back-diffusion plasma generator for ionosphere study

NASA Astrophysics Data System (ADS)

Fang, H. K.; Oyama, K.-I.; Chen, A. B.

2017-11-01

To produce ionospheric plasma environments at ground level is essential to get information not only for the development of CubeSat-class spacecraft but also for the design of ionospheric plasma instruments and to confirm their performance. In this paper, we describe the principle of plasma generation and characteristics of the back-diffusion plasma source, which can produce in-lab plasma similar to the Earth’s ionosphere, E and F regions, conditions of electron and ion temperature and density. The ion and electron energy distributions of the plasma generated by a back-diffusion source are measured by means of a cleaned Langmuir probe and gridded particle energy analyzers. The ion motion in front of the source is investigated by a hard-sphere collision model in SIMION software and the simulation results are comparable with the findings of our experiment. Furthermore, plasma densities and ion temperatures at different positions in front of the source are also demonstrated. The back-diffusion source has been accommodated for ionospheric plasma productions in several Asian institutes. The plasma characteristics of the source shown in this paper will benefit space research groups in the development of space plasma instruments.

High intensity proton injector for facility of antiproton and ion research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berezov, R., E-mail: r.berezov@gsi.de; Brodhage, R.; Fils, J.

The high current ion source with the low energy beam transport (LEBT) will serve as injector into the proton LINAC to provide primary proton beam for the production of antiprotons. The pulsed ion source developed and built in CEA/Saclay operates with a frequency of 2.45 GHz based on ECR plasma production with two coils with 87.5 mT magnetic field necessary for the electron cyclotron resonance. The compact LEBT consists of two solenoids with a maximum magnetic field of 500 mT including two integrated magnetic steerers to adjust the horizontal and vertical beam positions. The total length of the compact LEBTmore » is 2.3 m and was made as short as possible to reduced emittance growth along the beam line. To measure ion beam intensity behind the pentode extraction system, between solenoids and at the end of the beam line, two current transformers and a Faraday cup are installed. To get information about the beam quality and position, the diagnostic chamber with different equipment will be installed between the two solenoids. This article reports the current status of the proton injector for the facility of antiproton and ion research.« less

Investigation of High-Intensity Ion Beam Generation in the Diode with External Magnetic Insulation and Explosive Plasma Emission Source

NASA Astrophysics Data System (ADS)

Shamanin, V. I.; Stepanov, A. V.; Rysbaev, K. Zh.

2018-04-01

The ion Br-diode in which plasma is generated under the action of a negative pre-pulse voltage is presented. Preliminary plasma formation allows the energy released in the diode during a positive voltage pulse to be increased. The high-energy ion beam parameters are investigated for the magnetic field induction changing from 0.8Bcr to 1.7Bcr.

The effect of cavity tuning on oxygen beam currents of an A-ECR type 14 GHz electron cyclotron resonance ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tarvainen, O., E-mail: olli.tarvainen@jyu.fi; Orpana, J.; Kronholm, R.

2016-09-15

The efficiency of the microwave-plasma coupling plays a significant role in the production of highly charged ion beams with electron cyclotron resonance ion sources (ECRISs). The coupling properties are affected by the mechanical design of the ion source plasma chamber and microwave launching system, as well as damping of the microwave electric field by the plasma. Several experiments attempting to optimize the microwave-plasma coupling characteristics by fine-tuning the frequency of the injected microwaves have been conducted with varying degrees of success. The inherent difficulty in interpretation of the frequency tuning results is that the effects of microwave coupling system andmore » the cavity behavior of the plasma chamber cannot be separated. A preferable approach to study the effect of the cavity properties of the plasma chamber on extracted beam currents is to adjust the cavity dimensions. The results of such cavity tuning experiments conducted with the JYFL 14 GHz ECRIS are reported here. The cavity properties were adjusted by inserting a conducting tuner rod axially into the plasma chamber. The extracted beam currents of oxygen charge states O{sup 3+}–O{sup 7+} were recorded at various tuner positions and frequencies in the range of 14.00–14.15 GHz. It was observed that the tuner position affects the beam currents of high charge state ions up to several tens of percent. In particular, it was found that at some tuner position / frequency combinations the plasma exhibited “mode-hopping” between two operating regimes. The results improve the understanding of the role of plasma chamber cavity properties on ECRIS performances.« less

Infrared laser dissociation of single megadalton polymer ions in a gated electrostatic ion trap: the added value of statistical analysis of individual events.

PubMed

Halim, Mohammad A; Clavier, Christian; Dagany, Xavier; Kerleroux, Michel; Dugourd, Philippe; Dunbar, Robert C; Antoine, Rodolphe

2018-05-07

In this study, we report the unimolecular dissociation mechanism of megadalton SO 3 -containing poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) polymer cations and anions with the aid of infrared multiphoton dissociation coupled to charge detection ion trap mass spectrometry. A gated electrostatic ion trap ("Benner trap") is used to store and detect single gaseous polymer ions generated by positive and negative polarity in an electrospray ionization source. The trapped ions are then fragmented due to the sequential absorption of multiple infrared photons produced from a continuous-wave CO 2 laser. Several fragmentation pathways having distinct signatures are observed. Highly charged parent ions characteristically adopt a distinctive "stair-case" pattern (assigned to the "fission" process) whereas low charge species take on a "funnel like" shape (assigned to the "evaporation" process). Also, the log-log plot of the dissociation rate constants as a function of laser intensity between PAMPS positive and negative ions is significantly different.

Diagnosing the Fine Structure of Electron Energy Within the ECRIT Ion Source

NASA Astrophysics Data System (ADS)

Jin, Yizhou; Yang, Juan; Tang, Mingjie; Luo, Litao; Feng, Bingbing

2016-07-01

The ion source of the electron cyclotron resonance ion thruster (ECRIT) extracts ions from its ECR plasma to generate thrust, and has the property of low gas consumption (2 sccm, standard-state cubic centimeter per minute) and high durability. Due to the indispensable effects of the primary electron in gas discharge, it is important to experimentally clarify the electron energy structure within the ion source of the ECRIT through analyzing the electron energy distribution function (EEDF) of the plasma inside the thruster. In this article the Langmuir probe diagnosing method was used to diagnose the EEDF, from which the effective electron temperature, plasma density and the electron energy probability function (EEPF) were deduced. The experimental results show that the magnetic field influences the curves of EEDF and EEPF and make the effective plasma parameter nonuniform. The diagnosed electron temperature and density from sample points increased from 4 eV/2×1016 m-3 to 10 eV/4×1016 m-3 with increasing distances from both the axis and the screen grid of the ion source. Electron temperature and density peaking near the wall coincided with the discharge process. However, a double Maxwellian electron distribution was unexpectedly observed at the position near the axis of the ion source and about 30 mm from the screen grid. Besides, the double Maxwellian electron distribution was more likely to emerge at high power and a low gas flow rate. These phenomena were believed to relate to the arrangements of the gas inlets and the magnetic field where the double Maxwellian electron distribution exits. The results of this research may enhance the understanding of the plasma generation process in the ion source of this type and help to improve its performance. supported by National Natural Science Foundation of China (No. 11475137)

MASS SEPARATORS

DOEpatents

Oppenheimer, F.; Bell, J.W.

1959-02-17

An improvement in the mounting arrangement for the ion source within the vacuum tank of a calutron is presented. The entire source is supported by the vacuum envelope through the medium of a bracket secured to a removable face plate. The bracket forms a supporting platform that is generally transverse to the magnetic field. The ion generator is mounted on a pedestal-type insulator supported on the bracket, and the hot leads are brought into the vacuum envelope through a tubular elbow connected to the vacuum envelope, having the axis of its outer opening aligned with the magnetic field at which point a bushing-type insulator is employed. With this arrangement thc ion source is maintained at a positive potential with respect to the vacuum tank and the problem of electron bombardment of the insulator is considerably reduced.

Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro

2012-02-15

In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them inmore » detail.« less

A compact source for bunches of singly charged atomic ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murböck, T.; Birkl, G.; Schmidt, S.

2016-04-15

We have built, operated, and characterized a compact ion source for low-energy bunches of singly charged atomic ions in a vacuum beam line. It is based on atomic evaporation from an electrically heated oven and ionization by electron impact from a heated filament inside a grid-based ionization volume. An adjacent electrode arrangement is used for ion extraction and focusing by applying positive high-voltage pulses to the grid. The method is particularly suited for experimental environments which require low electromagnetic noise. It has proven simple yet reliable and has been used to produce μs-bunches of up to 10{sup 6} Mg{sup +}more » ions at a repetition rate of 1 Hz. We present the concept, setup and characterizing measurements. The instrument has been operated in the framework of the SpecTrap experiment at the HITRAP facility at GSI/FAIR to provide Mg{sup +} ions for sympathetic cooling of highly charged ions by laser-cooled {sup 24}Mg{sup +}.« less

Method and source for producing a high concentration of positively charged molecular hydrogen or deuterium ions

DOEpatents

Ehlers, K.W.; Leung, K.N.

1983-07-26

One principal object of the present invention is to provide a novel method and apparatus for generating a high concentration of H/sub 2//sup +/ or D/sub 2//sup +/ ions by using a new and improved multicusp ion source. The basic principle in achieving a high percentage of H/sub 2//sup +/ or D/sub 2//sup +/ ions is to extract them from the source as soon as they are produced. Otherwise they will react with background gas molecules to form tri-atomic ions H/sub 3//sup +/ or D/sub 3//sup +/ or be dissociated by electrons. The former reaction H/sub 2//sup +/ + H/sub 2/ ..-->.. H/sub 3//sup +/ + H can have a very short mean free path length lambda. Assuming a background neutral gas density of approximately 3.3 x 10/sup 13/ cm/sup -3/ and a cross-section sigma of approximately 6 x 10/sup -15/ cm/sup 2/, lambda = (n/sub 0/ sigma)/sup -1/ is estimated to be about 5 cm. Thus the distance traversed by the H/sub 2//sup +/ ion before it arrives at the extractor electrode cannot exceed this value. This in turn sets a limit on the length of the source chamber.

Application of Ni-63 photo and corona discharge ionization for the analysis of chemical warfare agents and toxic wastes

NASA Technical Reports Server (NTRS)

Stach, J.; Adler, J.; Brodacki, M.; Doring, H.-R.

1995-01-01

Over the past decade, advances in instrumental design and refinements in the understanding of ion molecule reactions at atmospheric pressure enabled the application of Ion Mobility Spectrometry (IMS) as a simple inexpensive and sensitive analytical method for the detection of organic trace compounds. Positive and negative gas-phase ions for ion mobility spectrometry have been produced by a variety of methods, including photo-ionization, laser multi photon ionization, surface ionization, corona discharge ionization. The most common ion source used in ion mobility spectrometry is a radioactive Ni-63 foil which is favored due to simplicity, stability, convenience, and high selectivity. If reactant ions like (H2O(n)H)(+) or (H2O(n)O2)(-) dominate in the reaction region, nearly all kinds of compounds with a given proton or electron affinity; are ionized. However, the radioactivity of the Ni-63 foil is one disadvantage of this ion source that stimulates the development and application of other ionization techniques. In this paper, we report analyses of old chemical warfare agents and toxic wastes using Bruker RAID ion mobility spectrometers. Due to the modular construction of the measuring cell, the spectrometers can be equipped with different ion sources. The combined use of Ni-63, photo- and corona discharge ionization allows the identification of different classes of chemical compounds and yields in most cases comparable results.

Neutral beamline with ion energy recovery based on magnetic blocking of electrons

DOEpatents

Stirling, William L.

1982-01-01

A neutral beamline generator with energy recovery of the full-energy ion ponent of the beam based on magnetic blocking of electrons is provided. Ions from a positive ion source are accelerated to the desired beam energy from a slightly positive potential level with respect to ground through a neutralizer cell by means of a negative acceleration voltage. The unneutralized full-energy ion component of the beam exiting the neutralizer are retarded and slightly deflected and the electrons in the neutralizer are blocked by a magnetic field generated transverse to the beamline. An electron collector in the form of a coaxial cylinder surrounding and protruding axial a few centimeters beyond the neutralizer exit terminates the electrons which exit the neutralizer in an E x B drift to the collector when the collector is biased a few hundred volts positive with respect to the neutralizer voltage. The neutralizer is operated at the negative acceleration voltage, and the deflected full energy ions are decelerated and the charge collected at ground potential thereby expending none of their energy received from the acceleration power supply.

High Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

DOEpatents

Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

2005-11-22

A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing a device for transmitting ions from an ion source which allows the transmission of ions without significant delay to an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

Studies on the effect of the axial magnetic field on the x-ray bremsstrahlung in a 2.45 GHz permanent magnet microwave ion source.

PubMed

Kumar, Narender; Rodrigues, G; Lakshmy, P S; Baskaran, R; Mathur, Y; Ahuja, R; Kanjilal, D

2014-02-01

A compact microwave ion source has been designed and developed for operation at a frequency of 2.45 GHz. The axial magnetic field is based on two permanent magnet rings, operating in the "off-resonance" mode and is tunable by moving the permanent magnets. In order to understand the electron energy distribution function, x-ray bremsstrahlung has been measured in the axial direction. Simulation studies on the x-ray bremsstrahlung have been carried out to compare with the experimental results. The effect of the axial magnetic field with respect to the microwave launching position and the position of the extraction electrode on the x-ray bremsstrahlung have been studied.

Electrostatic ion thruster optics calculations

NASA Technical Reports Server (NTRS)

Whealton, John H.; Kirkman, David A.; Raridon, R. J.

1992-01-01

Calculations have been performed which encompass both a self-consistent ion source extraction plasma sheath and the primary ion optics including sheath and electrode-induced aberrations. Particular attention is given to the effects of beam space charge, accelerator geometry, and properties of the downstream plasma sheath on the position of the electrostatic potential saddle point near the extractor electrode. The electron blocking potential blocking is described as a function of electrode thickness and secondary plasma processes.

Conversion of fullerenes to diamond

DOEpatents

Gruen, Dieter M.

1993-01-01

A method of forming synthetic diamond on a substrate is disclosed. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond thickness on the substrate.

Conversion of fullerenes to diamond

DOEpatents

Gruen, Dieter M.

1994-01-01

A method of forming synthetic diamond on a substrate. The method involves providing a substrate surface covered with a fullerene or diamond coating, positioning a fullerene in an ionization source, creating a fullerene vapor, ionizing fullerene molecules, accelerating the fullerene ions to energies above 250 eV to form a fullerene ion beam, impinging the fullerene ion beam on the substrate surface and continuing these steps to obtain a diamond film thickness on the substrate.

Monte Carlo study on secondary neutrons in passive carbon-ion radiotherapy: Identification of the main source and reduction in the secondary neutron dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yonai, Shunsuke; Matsufuji, Naruhiro; Kanai, Tatsuaki

Purpose: Recent successful results in passive carbon-ion radiotherapy allow the patient to live for a longer time and allow younger patients to receive the radiotherapy. Undesired radiation exposure in normal tissues far from the target volume is considerably lower than that close to the treatment target, but it is considered to be non-negligible in the estimation of the secondary cancer risk. Therefore, it is very important to reduce the undesired secondary neutron exposure in passive carbon-ion radiotherapy without influencing the clinical beam. In this study, the source components in which the secondary neutrons are produced during passive carbon-ion radiotherapy weremore » identified and the method to reduce the secondary neutron dose effectively based on the identification of the main sources without influencing the clinical beam was investigated. Methods: A Monte Carlo study with the PHITS code was performed by assuming the beamline at the Heavy-Ion Medical Accelerator in Chiba (HIMAC). At first, the authors investigated the main sources of secondary neutrons in passive carbon-ion radiotherapy. Next, they investigated the reduction in the neutron dose with various modifications of the beamline device that is the most dominant in the neutron production. Finally, they investigated the use of an additional shield for the patient. Results: It was shown that the main source is the secondary neutrons produced in the four-leaf collimator (FLC) used as a precollimator at HIAMC, of which contribution in the total neutron ambient dose equivalent is more than 70%. The investigations showed that the modification of the FLC can reduce the neutron dose at positions close to the beam axis by 70% and the FLC is very useful not only for the collimation of the primary beam but also the reduction in the secondary neutrons. Also, an additional shield for the patient is very effective to reduce the neutron dose at positions farther than 50 cm from the beam axis. Finally, they showed that the neutron dose can be reduced by approximately 70% at any position without influencing the primary beam used in treatment. Conclusions: This study was performed by assuming the HIMAC beamline; however, this study provides important information for reoptimizing the arrangement and the materials of beamline devices and designing a new facility for passive carbon-ion radiotherapy and probably passive proton radiotherapy.« less

Strong Turbulence in Alkali Halide Negative Ion Plasmas

NASA Astrophysics Data System (ADS)

Sheehan, Daniel

1999-11-01

Negative ion plasmas (NIPs) are charge-neutral plasmas in which the negative charge is dominated by negative ions rather than electrons. They are found in laser discharges, combustion products, semiconductor manufacturing processes, stellar atmospheres, pulsar magnetospheres, and the Earth's ionosphere, both naturally and man-made. They often display signatures of strong turbulence^1. Development of a novel, compact, unmagnetized alkali halide (MX) NIP source will be discussed, it incorporating a ohmically-heated incandescent (2500K) tantulum solenoid (3cm dia, 15 cm long) with heat shields. The solenoid ionizes the MX vapor and confines contaminant electrons, allowing a very dry (electron-free) source. Plasma densities of 10^10 cm-3 and positive to negative ion mass ratios of 1 <= fracm_+m- <= 20 are achievable. The source will allow tests of strong turbulence theory^2. 1 Sheehan, D.P., et al., Phys. Fluids B5, 1593 (1993). 2 Tsytovich, V. and Wharton, C.W., Comm. Plasma Phys. Cont. Fusion 4, 91 (1978).

Pickup Ion Velocity Distributions at Titan: Effects of Spatial Gradients

NASA Technical Reports Server (NTRS)

Hartle, R. E.; Sittler, E. C.

2004-01-01

The principle source of pickup ions at Titan is its neutral exosphere, extending well above the ionopause into the magnetosphere of Saturn or the solar wind, depending on the moon's orbital position. Thermal and nonthermal processes in the thermosphere generate the distribution of neutral atoms and molecules in the exosphere. The combination of these processes and the range of mass numbers, 1 to over 28, contribute to an exospheric source structure that produces pickup ions with gyroradii that are much larger or smaller than the corresponding scale heights of their neutral sources. The resulting phase space distributions are dependent on the spatial structure of the exosphere as well as that of the magnetic field and background plasma. When the pickup ion gyroradius is less than the source gas scale height, the pickup ion velocity distribution is characterized by a sharp cutoff near the maximum speed, which is twice that of the ambient plasma times the sine of the angle between the magnetic field and the flow velocity. This was the case for pickup H(sup +) ions identified during the Voyager 1 flyby. In contrast, as the gyroradius becomes much larger than the scale height, the peak of the velocity distribution in the source region recedes from the maximum speed. Iri addition, the amplitude of the distribution near the maximum speed decreases. These more beam like distributions of heavy ions were not observed from Voyager 1 , but should be observable by more sensitive instruments on future spacecraft, including Cassini. The finite gyroradius effects in the pickup ion velocity distributions are studied by including in the analysis the possible range of spatial structures in the neutral exosphere and background plasma.

Design of a compact, permanent magnet electron cyclotron resonance ion source for proton and H2(+) beam production.

PubMed

Jia, Xianlu; Zhang, Tianjue; Luo, Shan; Wang, Chuan; Zheng, Xia; Yin, Zhiguo; Zhong, Junqing; Wu, Longcheng; Qin, Jiuchang

2010-02-01

A 2.45 GHz microwave ion source was developed at China Institute of Atomic Energy (CIAE) for proton beam production of over 60 mA [B.-Q. Cui, Y.-W. Bao, L.-Q. Li, W.-S. Jiang, and R.-W. Wang, Proceedings of the High Current Electron Cyclotron Resonance (ECR) Ion Source for Proton Accelerator, APAC-2001, 2001 (unpublished)]. For various proton beam applications, another 2.45 GHz microwave ion source with a compact structure is designed and will be built at CIAE as well for high current proton beam production. It is also considered to be used for the test of H(2)(+) beam, which could be injected into the central region model cyclotron at CIAE, and accelerated to 5 MeV before extraction by stripping. The required ECR magnetic field is supplied by all the permanent magnets rather than electrical solenoids and six poles. The magnetic field distribution provided by this permanent magnets configuration is a large and uniformly volume of ECR zone, with central magnetic field of a magnitude of approximately 875 Gs [T. Taylor and J. S. C. Wills, Nucl. Instrum. Methods Phys. Res. A 309, 37 (1991)]. The field adjustment at the extraction end can be implemented by moving the position of the magnet blocks. The results of plasma, coupling with 2.45 GHz microwave in the ECR zone inside the ion source are simulated by particle-in-cell code to optimize the density by adjusting the magnetic field distribution. The design configuration of the ion source will be summarized in the paper.

Ion and electron sheath characteristics in a low density and low temperature plasma

NASA Astrophysics Data System (ADS)

Borgohain, Binita; Bailung, H.

2017-11-01

Ion and electron sheath characteristics in a low electron temperature (Te ˜ 0.25-0.40 eV) and density (ne ˜ 106-107 cm-3) plasma are described. The plasma is produced in the experimental volume through diffusion from a hot cathode discharge plasma source by using a magnetic filter. The electron energy distribution function in the experimental plasma volume is measured to be a narrow Maxwellian distribution indicating the absence of primary and energetic electrons which are decoupled in the source side by the cusp magnetic field near the filter. An emissive probe is used to measure the sheath potential profiles in front of a metal plate biased negative and positive with respect to the plasma potential. For a positive plate bias, the electron density decreases considerably and the electron sheath expands with a longer presheath region compared to the ion sheath. The sheath potential structures are found to follow the Debye sheath model.

Electrochemical Ionization and Analyte Charging in the Array of Micromachined UltraSonic Electrospray (AMUSE) Ion Source

PubMed Central

Forbes, Thomas P.; Degertekin, F. Levent; Fedorov, Andrei G.

2010-01-01

Electrochemistry and ion transport in a planar array of mechanically-driven, droplet-based ion sources are investigated using an approximate time scale analysis and in-depth computational simulations. The ion source is modeled as a controlled-current electrolytic cell, in which the piezoelectric transducer electrode, which mechanically drives the charged droplet generation using ultrasonic atomization, also acts as the oxidizing/corroding anode (positive mode). The interplay between advective and diffusive ion transport of electrochemically generated ions is analyzed as a function of the transducer duty cycle and electrode location. A time scale analysis of the relative importance of advective vs. diffusive ion transport provides valuable insight into optimality, from the ionization prospective, of alternative design and operation modes of the ion source operation. A computational model based on the solution of time-averaged, quasi-steady advection-diffusion equations for electroactive species transport is used to substantiate the conclusions of the time scale analysis. The results show that electrochemical ion generation at the piezoelectric transducer electrodes located at the back-side of the ion source reservoir results in poor ionization efficiency due to insufficient time for the charged analyte to diffuse away from the electrode surface to the ejection location, especially at near 100% duty cycle operation. Reducing the duty cycle of droplet/analyte ejection increases the analyte residence time and, in turn, improves ionization efficiency, but at an expense of the reduced device throughput. For applications where this is undesirable, i.e., multiplexed and disposable device configurations, an alternative electrode location is incorporated. By moving the charging electrode to the nozzle surface, the diffusion length scale is greatly reduced, drastically improving ionization efficiency. The ionization efficiency of all operating conditions considered is expressed as a function of the dimensionless Peclet number, which defines the relative effect of advection as compared to diffusion. This analysis is general enough to elucidate an important role of electrochemistry in ionization efficiency of any arrayed ion sources, be they mechanically-driven or electrosprays, and is vital for determining optimal design and operation conditions. PMID:20607111

A Combined Desorption Ionization by Charge Exchange (DICE) and Desorption Electrospray Ionization (DESI) Source for Mass Spectrometry

NASA Astrophysics Data System (ADS)

Chan, Chang-Ching; Bolgar, Mark S.; Miller, Scott A.; Attygalle, Athula B.

2011-01-01

A source that couples the desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) techniques together was demonstrated to broaden the range of compounds that can be analyzed in a single mass spectrometric experiment under ambient conditions. A tee union was used to mix the spray reagents into a partially immiscible blend before this mixture was passed through a conventional electrospray (ES) probe capillary. Using this technique, compounds that are ionized more efficiently by the DICE method and those that are ionized better with the DESI procedure could be analyzed simultaneously. For example, hydroquinone, which is not detected when subjected to DESI-MS in the positive-ion generation mode, or the sodium adduct of guaifenesin, which is not detected when examined by DICE-MS, could both be detected in one experiment when the two techniques were combined. The combined technique was able to generate the molecular ion, proton and metal adduct from the same compound. When coupled to a tandem mass spectrometer, the combined source enabled the generation of product ion spectra from the molecular ion and the [M + H]+ or [M + metal]+ ions of the same compound without the need to physically change the source from DICE to DESI. The ability to record CID spectra of both the molecular ion and adduct ions in a single mass spectrometric experiment adds a new dimension to the array of mass spectrometric methods available for structural studies.

Heavy Ion Formation in Titan's Ionosphere: Magnetospheric Introduction of Free Oxygen and Source of Titan's Aerosols?

NASA Technical Reports Server (NTRS)

Sittler, E. C., Jr.; Hartle, R. E.; Cooper, J. F.; Johnson, R. E.; Coates, A.; dePater, imke; Strom, Daphne; Simoes, F.; Steele, A.; Robb, F.

2007-01-01

With the recent discovery of heavy ions, positive and negative, by the Cassini Plasma Spectrometer (CAPS) instrument in Titan's ionosphere, it reveals new possibilities for aerosol formation at Titan and the introduction of free oxygen to the aerosol chemistry from Saturn's magnetosphere with Enceladus as the primary oxygen source. One can estimate whether the heavy ions in the ionosphere are of sufficient number to account for all the aerosols, under what conditions are favorable for heavy ion formation and how they are introduced as seed particles deeper in Titan's atmosphere where the aerosols form and eventually find themselves on Titan's surface where unknown chemical processes can take place. Finally, what are the possibilities with regard to their chemistry on the surface with some free oxygen present in their seed particles?

Sampling probe for microarray read out using electrospray mass spectrometry

DOEpatents

Van Berkel, Gary J.

2004-10-12

An automated electrospray based sampling system and method for analysis obtains samples from surface array spots having analytes. The system includes at least one probe, the probe including an inlet for flowing at least one eluting solvent to respective ones of a plurality of spots and an outlet for directing the analyte away from the spots. An automatic positioning system is provided for translating the probe relative to the spots to permit sampling of any spot. An electrospray ion source having an input fluidicly connected to the probe receives the analyte and generates ions from the analyte. The ion source provides the generated ions to a structure for analysis to identify the analyte, preferably being a mass spectrometer. The probe can be a surface contact probe, where the probe forms an enclosing seal along the periphery of the array spot surface.

Mirror-field confined compact plasma source using permanent magnet for plasma processings.

PubMed

Goto, Tetsuya; Sato, Kei-Ichiro; Yabuta, Yuki; Sugawa, Shigetoshi

2016-12-01

A mirror-field confined compact electron cyclotron resonance (ECR) plasma source using permanent magnets was developed, aiming for the realization of high-quality plasma processings where high-density reactive species are supplied to a substrate with minimizing the ion bombardment damages. The ECR position was located between a microwave transmissive window and a quartz limiter, and plasmas were transported from the ECR position to a midplane of the magnetic mirror field through the quartz limiter. Thus, a radius of core plasma could be determined by the limiter, which was 15 mm in this study. Plasma parameters were investigated by the Langmuir probe measurement. High-density plasma larger than 10 11 cm -3 could be produced by applying 5.85-GHz microwave power of 10 W or more. For the outside region of the core plasma where a wafer for plasma processings will be set at, the ion current density was decreased dramatically with distance from the core plasma and became smaller by approximately two orders of magnitude that in the core plasma region for the radial position of 40 mm, suggesting the realization of reduction in ion bombardment damages.

Ion propagation in an aluminum hollow cylinder target laser ion source

NASA Astrophysics Data System (ADS)

Saquilayan, Glynnis Mae Q.; Wada, Motoi

2018-01-01

Experimental results for the laser produced plasma in an aluminum hollow cylinder target are presented. Observing the plasma formation inside the cylinder, a high-speed camera captured the images of the plasma expanding towards the adjacent walls of target. The optical emission spectrum is obtained for the plasma inside the hollow cylinder and positive singly charged aluminum ions and neutrals are identified from emission spectral lines. Time dependent current signals of the Faraday cup displayed an enlarged signal intensity as the laser power density is increased up to 6.5 GW/cm2. Signal arrival times corresponding to fast ions appeared at the onset of the current waveforms when the laser power density exceeded 4.7 GW/cm2. For the mass analysis of plasma, an accelerating electric field was applied to separate the ions and the time-of-flight measurements showed positive ion signals with an identified peak to have an estimated mass of 350 amu.

Generalization of the Child-Langmuir law to the alternate extraction of positive and negative ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lafleur, T., E-mail: trevor.lafleur@lpp.polytechnique.fr; ONERA-The French Aerospace Lab, 91120 Palaiseau; Aanesland, A.

Using a combined analytical and simulation approach, we investigate positive and negative ion extraction between two electrodes from an ion-ion plasma source. With a square voltage waveform applied to the electrodes, we obtain approximate analytical solutions for the time-averaged extracted current densities, which are given simply by: J{sub p}{sup ac}=[α−fL√((M{sub p})/(q{sub p}V{sub 0}) )]J{sub p}{sup dc}, and J{sub n}{sup ac}=[(1−α)−fL√((M{sub n})/(q{sub n}V{sub 0}) )]J{sub n}{sup dc}, where J{sup ac} is the time-averaged current density, α is the square waveform duty cycle, f is the frequency, L is the electrode gap length, M is the ion mass, q is the ionmore » charge, V{sub 0} is the applied voltage amplitude, J{sup dc} is the dc extracted current density, and the subscripts p and n refer to positive and negative ions, respectively. In particular, if J{sup dc} is the dc space-charge limited current density, then these equations describe the square waveform generalization of the Child-Langmuir law.« less

Neutral beamline with ion energy recovery based on magnetic blocking of electrons

DOEpatents

Stirling, W.L.

1980-07-01

A neutral beamline generator with energy recovery of the full-energy ion component of the beam based on magnetic blocking of electrons is provided. Ions from a positive ion source are accelerated to the desired beam energy from a slightly positive potential level with respect to ground through a neutralizer cell by means of a negative acceleration voltage. The unneutralized full-energy ion component of the beam exiting the neutralizer are retarded and slightly deflected and the elecrons in the neutralizer are blocked by a magnetic field generated transverse to the beamline. An electron collector in the form of a coaxial cylinder surrounding and protruding axial a few centimeters beyond the neutralizer exit terminates the electrons which exit the neutralizer in an E x B drift to the collector when the collector is biased a few hundred volts positive with respect to the neutralizer voltage. The neutralizer is operated at the negative acceleration voltage. The neutralizer is operated at the negative acceleration voltage, and the deflected full energy ions are decelerated and the charge collected at ground potential thereby expending none of their energy received from the acceleration power supply.

Aerosol Vacuum-Assisted Plasma Ionization (Aero-VaPI) Coupled to Ion Mobility-Mass Spectrometry

NASA Astrophysics Data System (ADS)

Blair, Sandra L.; Ng, Nga L.; Zambrzycki, Stephen C.; Li, Anyin; Fernández, Facundo M.

2018-02-01

In this communication, we report on the real-time analysis of organic aerosol particles by Vacuum-assisted Plasma Ionization-Mass Spectrometry (Aero-VaPI-MS) using a home-built VaPI ion source coupled to a Synapt G2-S HDMS ion mobility-mass spectrometry (IM-MS) system. Standards of organic molecules of interest in prebiotic chemistry were used to generate aerosols. Monocaprin and decanoic acid aerosol particles were successfully detected in both the positive and negative ion modes, respectively. A complex aerosol mixture of different sizes of polymers of L-malic acid was also examined through ion mobility (IM) separations, resulting in the detection of polymers of up to eight monomeric units. This noncommercial plasma ion source is proposed as a low cost alternative to other plasma ionization platforms used for aerosol analysis, and a higher-performance alternative to more traditional aerosol mass spectrometers. VaPI provides robust online ionization of organics in aerosols without extensive ion activation, with the coupling to IM-MS providing higher peak capacity and excellent mass accuracy. [Figure not available: see fulltext.

Ion Beam Facilities at the National Centre for Accelerator based Research using a 3 MV Pelletron Accelerator

NASA Astrophysics Data System (ADS)

Trivedi, T.; Patel, Shiv P.; Chandra, P.; Bajpai, P. K.

A 3.0 MV (Pelletron 9 SDH 4, NEC, USA) low energy ion accelerator has been recently installed as the National Centre for Accelerator based Research (NCAR) at the Department of Pure & Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur, India. The facility is aimed to carried out interdisciplinary researches using ion beams with high current TORVIS (for H, He ions) and SNICS (for heavy ions) ion sources. The facility includes two dedicated beam lines, one for ion beam analysis (IBA) and other for ion implantation/ irradiation corresponding to switching magnet at +20 and -10 degree, respectively. Ions with 60 kV energy are injected into the accelerator tank where after stripping positively charged ions are accelerated up to 29 MeV for Au. The installed ion beam analysis techniques include RBS, PIXE, ERDA and channelling.

A multicentre audit of HDR/PDR brachytherapy absolute dosimetry in association with the INTERLACE trial (NCT015662405).

PubMed

Díez, P; Aird, E G A; Sander, T; Gouldstone, C A; Sharpe, P H G; Lee, C D; Lowe, G; Thomas, R A S; Simnor, T; Bownes, P; Bidmead, M; Gandon, L; Eaton, D; Palmer, A L

2017-11-09

A UK multicentre audit to evaluate HDR and PDR brachytherapy has been performed using alanine absolute dosimetry. This is the first national UK audit performing an absolute dose measurement at a clinically relevant distance (20 mm) from the source. It was performed in both INTERLACE (a phase III multicentre trial in cervical cancer) and non-INTERLACE brachytherapy centres treating gynaecological tumours. Forty-seven UK centres (including the National Physical Laboratory) were visited. A simulated line source was generated within each centre's treatment planning system and dwell times calculated to deliver 10 Gy at 20 mm from the midpoint of the central dwell (representative of Point A of the Manchester system). The line source was delivered in a water-equivalent plastic phantom (Barts Solid Water) encased in blocks of PMMA (polymethyl methacrylate) and charge measured with an ion chamber at 3 positions (120° apart, 20 mm from the source). Absorbed dose was then measured with alanine at the same positions and averaged to reduce source positional uncertainties. Charge was also measured at 50 mm from the source (representative of Point B of the Manchester system). Source types included 46 HDR and PDR 192 Ir sources, (7 Flexisource, 24 mHDR-v2, 12 GammaMed HDR Plus, 2 GammaMed PDR Plus, 1 VS2000) and 1 HDR 60 Co source, (Co0.A86). Alanine measurements when compared to the centres' calculated dose showed a mean difference (±SD) of  +1.1% (±1.4%) at 20 mm. Differences were also observed between source types and dose calculation algorithm. Ion chamber measurements demonstrated significant discrepancies between the three holes mainly due to positional variation of the source within the catheter (0.4%-4.9% maximum difference between two holes). This comprehensive audit of absolute dose to water from a simulated line source showed all centres could deliver the prescribed dose to within 5% maximum difference between measurement and calculation.

Neutron tubes

DOEpatents

Leung, Ka-Ngo [Hercules, CA; Lou, Tak Pui [Berkeley, CA; Reijonen, Jani [Oakland, CA

2008-03-11

A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides

NASA Astrophysics Data System (ADS)

McMillen, Chelsea L.; Wright, Patience M.; Cassady, Carolyn J.

2016-05-01

Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

Negative Ion In-Source Decay Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry for Sequencing Acidic Peptides.

PubMed

McMillen, Chelsea L; Wright, Patience M; Cassady, Carolyn J

2016-05-01

Matrix-assisted laser desorption/ionization (MALDI) in-source decay was studied in the negative ion mode on deprotonated peptides to determine its usefulness for obtaining extensive sequence information for acidic peptides. Eight biological acidic peptides, ranging in size from 11 to 33 residues, were studied by negative ion mode ISD (nISD). The matrices 2,5-dihydroxybenzoic acid, 2-aminobenzoic acid, 2-aminobenzamide, 1,5-diaminonaphthalene, 5-amino-1-naphthol, 3-aminoquinoline, and 9-aminoacridine were used with each peptide. Optimal fragmentation was produced with 1,5-diaminonphthalene (DAN), and extensive sequence informative fragmentation was observed for every peptide except hirudin(54-65). Cleavage at the N-Cα bond of the peptide backbone, producing c' and z' ions, was dominant for all peptides. Cleavage of the N-Cα bond N-terminal to proline residues was not observed. The formation of c and z ions is also found in electron transfer dissociation (ETD), electron capture dissociation (ECD), and positive ion mode ISD, which are considered to be radical-driven techniques. Oxidized insulin chain A, which has four highly acidic oxidized cysteine residues, had less extensive fragmentation. This peptide also exhibited the only charged localized fragmentation, with more pronounced product ion formation adjacent to the highly acidic residues. In addition, spectra were obtained by positive ion mode ISD for each protonated peptide; more sequence informative fragmentation was observed via nISD for all peptides. Three of the peptides studied had no product ion formation in ISD, but extensive sequence informative fragmentation was found in their nISD spectra. The results of this study indicate that nISD can be used to readily obtain sequence information for acidic peptides.

Three-dimensional modeling of a negative ion source with a magnetic filter: impact of biasing the plasma electrode on the plasma asymmetry

NASA Astrophysics Data System (ADS)

Fubiani, G.; Boeuf, J. P.

2015-10-01

The effect on the plasma characteristics of biasing positively the plasma electrode (PE) in negative ion sources with a magnetic filter is analysed using a 3D particle-in-cell model with Monte-Carlo collisions (PIC-MCC). We specialize to the one driver (i.e. one inductively coupled radio-frequency discharge) BATMAN negative ion source and the 4-drivers (large volume) ELISE device. Both are ITER prototype high power tandem-type negative ion sources developed for the neutral beam injector (NBI) system. The plasma is generated in the driver and diffuses inside the second chamber which is magnetized. Asymmetric plasma profiles originate from the formation of an electric field transverse to the electron current flowing through the magnetic filter (Hall effect). The model shows that the importance of the asymmetry increases with the PE bias potential, i.e. with the electron flow from the driver to the extraction region and depends on the shape of the magnetic filter field. We find that although the plasma density and potential profiles may be more or less asymmetric depending on the filter field configuration, the electron current to the plasma grid is always strongly asymmetric.

Penning discharge ion source with self-cleaning aperture

DOEpatents

Gavin, B.F.; MacGill, R.A.; Thatcher, R.K.

1980-11-10

An ion source of the Penning discharge type having a self-cleaning aperture is provided by a second dynode with an exit aperture in a position opposite a first dynode, from which the ions are sputtered, two opposing cathodes, each with an anode for accelerating electrons emitted from the cathodes into a cylindrical space defined by the first and second dynode. A support gas maintained in this space is ionized by the electrons. While the cathodes are supplied with a negative pulse to emit electrons, the first dynode is supplied with a negative pulse (e.g., -300 V) to attract atoms of the ionized gas (plasma). At the same time, the second dynode may also be supplied with a small voltage that is negative with respect to the plasma (e.g., -5 V) for tuning the position of the plasma miniscus for optimum extraction geometry. When the negative pulse to the first dynode is terminated, the second dynode is driven strongly negative (e.g., -600 V) thereby allowing heavy sputtering to take place for a short period to remove virtually all of the atoms deposited on the second dynode from material sputtered off the first dynode. An extractor immediately outside the exit aperture of the second dynode is maintained at ground potential while the anode, dynode, and cathode reference voltage is driven strongly positive (about +20 kV to +30 kV) so that ions accelerated through the aperture will be at ground potential. Material from the first dynode deposited on the second dynode will be sputtered, in time, to add to the ion beam.

ION ROCKET ENGINE

DOEpatents

Ehlers, K.W.; Voelker, F. III

1961-12-19

A thrust generating engine utilizing cesium vapor as the propellant fuel is designed. The cesium is vaporized by heat and is passed through a heated porous tungsten electrode whereby each cesium atom is fonized. Upon emergfng from the tungsten electrode, the ions are accelerated rearwardly from the rocket through an electric field between the tungsten electrode and an adjacent accelerating electrode grid structure. To avoid creating a large negative charge on the space craft as a result of the expulsion of the positive ions, a source of electrons is disposed adjacent the ion stream to neutralize the cesium atoms following acceleration thereof. (AEC)

UV-POSIT: Web-Based Tools for Rapid and Facile Structural Interpretation of Ultraviolet Photodissociation (UVPD) Mass Spectra

NASA Astrophysics Data System (ADS)

Rosenberg, Jake; Parker, W. Ryan; Cammarata, Michael B.; Brodbelt, Jennifer S.

2018-04-01

UV-POSIT (Ultraviolet Photodissociation Online Structure Interrogation Tools) is a suite of web-based tools designed to facilitate the rapid interpretation of data from native mass spectrometry experiments making use of 193 nm ultraviolet photodissociation (UVPD). The suite includes four separate utilities which assist in the calculation of fragment ion abundances as a function of backbone cleavage sites and sequence position; the localization of charge sites in intact proteins; the calculation of hydrogen elimination propensity for a-type fragment ions; and mass-offset searching of UVPD spectra to identify unknown modifications and assess false positive fragment identifications. UV-POSIT is implemented as a Python/Flask web application hosted at http://uv-posit.cm.utexas.edu. UV-POSIT is available under the MIT license, and the source code is available at https://github.com/jarosenb/UV_POSIT. [Figure not available: see fulltext.

UV-POSIT: Web-Based Tools for Rapid and Facile Structural Interpretation of Ultraviolet Photodissociation (UVPD) Mass Spectra.

PubMed

Rosenberg, Jake; Parker, W Ryan; Cammarata, Michael B; Brodbelt, Jennifer S

2018-06-01

UV-POSIT (Ultraviolet Photodissociation Online Structure Interrogation Tools) is a suite of web-based tools designed to facilitate the rapid interpretation of data from native mass spectrometry experiments making use of 193 nm ultraviolet photodissociation (UVPD). The suite includes four separate utilities which assist in the calculation of fragment ion abundances as a function of backbone cleavage sites and sequence position; the localization of charge sites in intact proteins; the calculation of hydrogen elimination propensity for a-type fragment ions; and mass-offset searching of UVPD spectra to identify unknown modifications and assess false positive fragment identifications. UV-POSIT is implemented as a Python/Flask web application hosted at http://uv-posit.cm.utexas.edu . UV-POSIT is available under the MIT license, and the source code is available at https://github.com/jarosenb/UV_POSIT . Graphical Abstract.

Studies on the Extraction Region of the Type VI RF Driven H- Ion Source

NASA Astrophysics Data System (ADS)

McNeely, P.; Bandyopadhyay, M.; Franzen, P.; Heinemann, B.; Hu, C.; Kraus, W.; Riedl, R.; Speth, E.; Wilhelm, R.

2002-11-01

IPP Garching has spent several years developing a RF driven H- ion source intended to be an alternative to the current ITER (International Thermonuclear Experimental Reactor) reference design ion source. A RF driven source offers a number of advantages to ITER in terms of reduced costs and maintenance requirements. Although the RF driven ion source has shown itself to be competitive with a standard arc filament ion source for positive ions many questions still remain on the physics behind the production of the H- ion beam extracted from the source. With the improvements that have been implemented to the BATMAN (Bavarian Test Machine for Negative Ions) facility over the last two years it is now possible to study both the extracted ion beam and the plasma in the vicinity of the extraction grid in greater detail. This paper will show the effect of changing the extraction and acceleration voltage on both the current and shape of the beam as measured on the calorimeter some 1.5 m downstream from the source. The extraction voltage required to operate in the plasma limit is 3 kV. The perveance optimum for the extraction system was determined to be 2.2 x 10-6 A/V3/2 and occurs at 2.7 kV extraction voltage. The horizontal and vertical beam half widths vary as a function of the extracted ion current and the horizontal half width is generally smaller than the vertical. The effect of reducing the co-extracted electron current via plasma grid biasing on the H- current extractable and the beam profile from the source is shown. It is possible in the case of a silver contaminated plasma to reduce the co-extracted electron current to 20% of the initial value by applying a bias of 12 V. In the case where argon is present in the plasma, biasing is observed to have minimal effect on the beam half width but in a pure hydrogen plasma the beam half width increases as the bias voltage increases. New Langmuir probe studies that have been carried out parallel to the plasma grid (in the vicinity of the peak of the external magnetic filter field) and changes to source parameters as a function of power, and argon addition are reported. The behaviour of the electron density is different when the plasma is argon seeded showing a strong increase with RF power. The plasma potential is decreased by 2 V when argon is added to the plasma. The effect of the presence of unwanted silver sputtered from the Faraday screen by Ar+ ions on both the source performance and the plasma parameters is also presented. The silver dramatically downgraded source performance in terms of current density and produced an early saturation of current with applied RF power. Recently, collaboration was begun with the Technical University of Augsburg to perform spectroscopic measurements on the Type VI ion source. The final results of this analysis are not yet ready but some interesting initial observations on the gas temperature, disassociation degree and impurity ions will be presented.

Laboratory Studies in UV and EUV Solar Physics

NASA Technical Reports Server (NTRS)

Parkinson, William

2003-01-01

The Ion Beam Experiment at the Center for Astrophysics is dedicated to the study of ion-electron collision processes of importance in solar physics. A paper describing our most recent measurement 'Absolute cross section for Si(2+)(3s3p(sup 3)Rho (sup 0) yields 3s3p(sup 1)Rho(sup 0)) electron-impact excitation' was published during the past year. Dr. Paul Janzen received his PhD. from the Harvard Physics Department on the basis of this and other work, such as the new electron cyclotron resonance (ECR) ion source. The ion source is producing stable beams with large currents for our present work on C(2+), and it also produces stable beams with large currents of more highly charged systems, for future work on systems such as O(4+). The past year has been focussed on our current program to measure absolute cross sections for Electron Impact Excitation (EIE) in C(2+), one of the primary ions used for probing the solar transition region. C(2+) beams produced by the ion source have been transported to the interaction region of the experiment, where the collisions are studied, and Visiting Scientist Dr. Adrian Daw is currently collecting data to measure the C(2+)(2s2p(sup 3)Rho(sup 0) yields 2p(sup 2)(sup 3)Rho) EIE cross section as a function of collision energy, under the guidance of Drs. John Kohl, Larry Gardner and Bill Parkinson. Also this year, modifications were made to the ECR ion source in order to produce greater currents of highly charged ions. Testing of the ion source was completed. Modifications were designed to extend the photon detection capabilities of the apparatus to shorter UV wavelengths, or EUV. Following the work on C(2+)(2s2p(sup 3)Pho(sup 0) yields 2p(sup 2)(sup 3)Rho), the extended UV detection capabilities will be used to measure the C(2+)(2s(sup 2)(sup 1)S yields 2s2p(sup 1)Rho(sup 0)) EIE cross section. The EUV modifications complement those of the new ion source, by enabling detection of EUV light generated by high charge state ions and putting us in a position to measure the excitation cross sections for more highly charged ions as well.

Ion Beam Neutralization Using FEAs and Mirror Magnetic Fields

NASA Astrophysics Data System (ADS)

Nicolaescu, Dan; Sakai, Shigeki; Gotoh, Yasuhito; Ishikawa, Junzo

2011-01-01

Advanced implantation systems used for semiconductor processing require transportation of ion beams which are quasi-parallel and have low energy, such as (11B+,31P+,75As+) with energy in the range Eion = 200-1000 eV. Compensation of ion beam divergence may be obtained through electron injection and confinement in regions of non-uniform magnetic fields. Field emitter arrays with special properties are used as electron sources. The present study shows that electron confinement takes place in regions of gradient magnetic field, such as nearby analyzing, collimator and final energy magnets of the ion beam line. Modeling results have been obtained using Opera3D/Tosca/Scala. In regions of gradient magnetic field, electrons have helical trajectories which are confined like a cloud inside curved "magnetic bottles". An optimal range of positions with respect to the magnet for placing electron sources in gradient magnetic field has been shown to exist.

Single particle mass spectral signatures from vehicle exhaust particles and the source apportionment of on-line PM2.5 by single particle aerosol mass spectrometry.

PubMed

Yang, Jian; Ma, Shexia; Gao, Bo; Li, Xiaoying; Zhang, Yanjun; Cai, Jing; Li, Mei; Yao, Ling'ai; Huang, Bo; Zheng, Mei

2017-09-01

In order to accurately apportion the many distinct types of individual particles observed, it is necessary to characterize fingerprints of individual particles emitted directly from known sources. In this study, single particle mass spectral signatures from vehicle exhaust particles in a tunnel were performed. These data were used to evaluate particle signatures in a real-world PM 2.5 apportionment study. The dominant chemical type originating from average positive and negative mass spectra for vehicle exhaust particles are EC species. Four distinct particle types describe the majority of particles emitted by vehicle exhaust particles in this tunnel. Each particle class is labeled according to the most significant chemical features in both average positive and negative mass spectral signatures, including ECOC, NaK, Metal and PAHs species. A single particle aerosol mass spectrometry (SPAMS) was also employed during the winter of 2013 in Guangzhou to determine both the size and chemical composition of individual atmospheric particles, with vacuum aerodynamic diameter (d va ) in the size range of 0.2-2μm. A total of 487,570 particles were chemically analyzed with positive and negative ion mass spectra and a large set of single particle mass spectra was collected and analyzed in order to identify the speciation. According to the typical tracer ions from different source types and classification by the ART-2a algorithm which uses source fingerprints for apportioning ambient particles, the major sources of single particles were simulated. Coal combustion, vehicle exhaust, and secondary ion were the most abundant particle sources, contributing 28.5%, 17.8%, and 18.2%, respectively. The fraction with vehicle exhaust species particles decreased slightly with particle size in the condensation mode particles. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced production of electron cyclotron resonance plasma by exciting selective microwave mode on a large-bore electron cyclotron resonance ion source with permanent magnet.

PubMed

Kimura, Daiju; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

2014-02-01

We are constructing a tandem type ECRIS. The first stage is large-bore with cylindrically comb-shaped magnet. We optimize the ion beam current and ion saturation current by a mobile plate tuner. They change by the position of the plate tuner for 2.45 GHz, 11-13 GHz, and multi-frequencies. The peak positions of them are close to the position where the microwave mode forms standing wave between the plate tuner and the extractor. The absorbed powers are estimated for each mode. We show a new guiding principle, which the number of efficient microwave mode should be selected to fit to that of multipole of the comb-shaped magnets. We obtained the excitation of the selective modes using new mobile plate tuner to enhance ECR efficiency.

An exploratory study of recycled sputtering and CsF2- current enhancement for AMS

NASA Astrophysics Data System (ADS)

Zhao, X.-L.; Charles, C. R. J.; Cornett, R. J.; Kieser, W. E.; MacDonald, C.; Kazi, Z.; St-Jean, N.

2016-01-01

The analysis of 135Cs/Cs ratios at levels below 10-12 by accelerator mass spectrometry (AMS) would preferably use commonly available negative ion injection systems. The sputter ion sources in these injectors should ideally produce currents of Cs- or Cs-containing molecular anions approaching μA levels from targets containing mg quantities of Cs. However, since Cs is the most electro-positive stable element in nature with a low electron affinity, the generation of large negative atomic, or molecular beams containing Cs, has been very challenging. In addition, the reduction of the interferences from the 135Ba isobar and the primary 133Cs+ beam used for sputtering are also necessary. The measurement of a wide range of the isotope ratios also requires the ion source memory of previous samples be minimized. This paper describes some progresses towards a potential solution of all these problems by recycled sputtering using fluorinating targets of PbF2 with mg CsF mixed in. The problems encountered indicate that considerable further studies and some redesign of the present ion sources will be desirable.

Operating characteristics of a new ion source for KSTAR neutral beam injection system.

PubMed

Kim, Tae-Seong; Jeong, Seung Ho; Chang, Doo-Hee; Lee, Kwang Won; In, Sang-Ryul

2014-02-01

A new positive ion source for the Korea Superconducting Tokamak Advanced Research neutral beam injection (KSTAR NBI-1) system was designed, fabricated, and assembled in 2011. The characteristics of the arc discharge and beam extraction were investigated using hydrogen and helium gas to find the optimum operating parameters of the arc power, filament voltage, gas pressure, extracting voltage, accelerating voltage, and decelerating voltage at the neutral beam test stand at the Korea Atomic Energy Research Institute in 2012. Based on the optimum operating condition, the new ion source was then conditioned, and performance tests were primarily finished. The accelerator system with enlarged apertures can extract a maximum 65 A ion beam with a beam energy of 100 keV. The arc efficiency and optimum beam perveance, at which the beam divergence is at a minimum, are estimated to be 1.0 A/kW and 2.5 uP, respectively. The beam extraction tests show that the design goal of delivering a 2 MW deuterium neutral beam into the KSTAR Tokamak plasma is achievable.

2-Aminobenzamide and 2-Aminobenzoic Acid as New MALDI Matrices Inducing Radical Mediated In-Source Decay of Peptides and Proteins

NASA Astrophysics Data System (ADS)

Smargiasso, Nicolas; Quinton, Loic; de Pauw, Edwin

2012-03-01

One of the mechanisms leading to MALDI in-source decay (MALDI ISD) is the transfer of hydrogen radicals to analytes upon laser irradiation. Analytes such as peptides or proteins may undergo ISD and this method can therefore be exploited for top-down sequencing. When performed on peptides, radical-induced ISD results in production of c- and z-ions, as also found in ETD and ECD activation. Here, we describe two new compounds which, when used as MALDI matrices, are able to efficiently induce ISD of peptides and proteins: 2-aminobenzamide and 2-aminobenzoic acid. In-source reduction of the disulfide bridge containing peptide Calcitonin further confirmed the radicalar mechanism of the ISD process. ISD of peptides led, in addition to c- and z-ions, to the generation of a-, x-, and y-ions both in positive and in negative ion modes. Finally, good sequence coverage was obtained for the sequencing of myoglobin (17 kDa protein), confirming the effectiveness of both 2-aminobenzamide and 2-aminobenzoic acid as MALDI ISD matrices.

2-Aminobenzamide and 2-aminobenzoic acid as new MALDI matrices inducing radical mediated in-source decay of peptides and proteins.

PubMed

Smargiasso, Nicolas; Quinton, Loic; De Pauw, Edwin

2012-03-01

One of the mechanisms leading to MALDI in-source decay (MALDI ISD) is the transfer of hydrogen radicals to analytes upon laser irradiation. Analytes such as peptides or proteins may undergo ISD and this method can therefore be exploited for top-down sequencing. When performed on peptides, radical-induced ISD results in production of c- and z-ions, as also found in ETD and ECD activation. Here, we describe two new compounds which, when used as MALDI matrices, are able to efficiently induce ISD of peptides and proteins: 2-aminobenzamide and 2-aminobenzoic acid. In-source reduction of the disulfide bridge containing peptide Calcitonin further confirmed the radicalar mechanism of the ISD process. ISD of peptides led, in addition to c- and z-ions, to the generation of a-, x-, and y-ions both in positive and in negative ion modes. Finally, good sequence coverage was obtained for the sequencing of myoglobin (17 kDa protein), confirming the effectiveness of both 2-aminobenzamide and 2-aminobenzoic acid as MALDI ISD matrices.

Modeling of negative ion extraction from a magnetized plasma source: Derivation of scaling laws and description of the origins of aberrations in the ion beam

NASA Astrophysics Data System (ADS)

Fubiani, G.; Garrigues, L.; Boeuf, J. P.

2018-02-01

We model the extraction of negative ions from a high brightness high power magnetized negative ion source. The model is a Particle-In-Cell (PIC) algorithm with Monte-Carlo Collisions. The negative ions are generated only on the plasma grid surface (which separates the plasma from the electrostatic accelerator downstream). The scope of this work is to derive scaling laws for the negative ion beam properties versus the extraction voltage (potential of the first grid of the accelerator) and plasma density and investigate the origins of aberrations on the ion beam. We show that a given value of the negative ion beam perveance correlates rather well with the beam profile on the extraction grid independent of the simulated plasma density. Furthermore, the extracted beam current may be scaled to any value of the plasma density. The scaling factor must be derived numerically but the overall gain of computational cost compared to performing a PIC simulation at the real plasma density is significant. Aberrations appear for a meniscus curvature radius of the order of the radius of the grid aperture. These aberrations cannot be cancelled out by switching to a chamfered grid aperture (as in the case of positive ions).

Groundwater chemistry and occurrence of arsenic in the Meghna floodplain aquifer, southeastern Bangladesh

USGS Publications Warehouse

Zahid, A.; Hassan, M.Q.; Balke, K.-D.; Flegr, M.; Clark, D.W.

2008-01-01

Dissolved major ions and important heavy metals including total arsenic and iron were measured in groundwater from shallow (25-33 m) and deep (191-318 m) tube-wells in southeastern Bangladesh. These analyses are intended to help describe geochemical processes active in the aquifers and the source and release mechanism of arsenic in sediments for the Meghna Floodplain aquifer. The elevated Cl- and higher proportions of Na+ relative to Ca2+, Mg2+, and K+ in groundwater suggest the influence by a source of Na+ and Cl-. Use of chemical fertilizers may cause higher concentrations of NH 4+ and PO 43- in shallow well samples. In general, most ions are positively correlated with Cl-, with Na+ showing an especially strong correlation with Cl-, indicating that these ions are derived from the same source of saline waters. The relationship between Cl-/HCO 3- ratios and Cl- also shows mixing of fresh groundwater and seawater. Concentrations of dissolved HCO 3- reflect the degree of water-rock interaction in groundwater systems and integrated microbial degradation of organic matter. Mn and Fe-oxyhydroxides are prominent in the clayey subsurface sediment and well known to be strong adsorbents of heavy metals including arsenic. All five shallow well samples had high arsenic concentration that exceeded WHO recommended limit for drinking water. Very low concentrations of SO 42- and NO 3- and high concentrations of dissolved Fe and PO 43- and NH 4+ ions support the reducing condition of subsurface aquifer. Arsenic concentrations demonstrate negative co-relation with the concentrations of SO 42- and NO 3- but correlate weakly with Mo, Fe concentrations and positively with those of P, PO 43- and NH 4+ ions. ?? 2007 Springer-Verlag.

The Thermal Ion Dynamics Experiment and Plasma Source Instrument

NASA Technical Reports Server (NTRS)

Moore, T. E.; Chappell, C. R.; Chandler, M. O.; Fields, S. A.; Pollock, C. J.; Reasoner, D. L.; Young, D. T.; Burch, J. L.; Eaker, N.; Waite, J. H., Jr.;

Linear electric field time-of-flight ion mass spectrometer

DOEpatents

Funsten, Herbert O [Los Alamos, NM; Feldman, William C [Los Alamos, NM

2008-06-10

A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

Three chamber negative ion source

DOEpatents

Leung, Ka-Ngo; Ehlers, Kenneth W.; Hiskes, John R.

1985-01-01

A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential.

Golf ball-assisted electrospray ionization of mass spectrometry for the determination of trace amino acids in complex samples.

PubMed

Li, Yen-Hsien; Chen, Chung-Yu; Kuo, Cheng-Hsiung; Lee, Maw-Rong

2016-09-28

During the electrospray ionization (ESI) process, ions move through a heated capillary aperture to be detected on arrival at a mass analyzer. However, the ESI process creates an ion plume, which expands into an ion cloud with an area larger than that of the heated capillary aperture, significantly contributing to an ion loss of 50% due to coulombic repulsion. The use of DC and RF fields to focus ions from the ion source into the vacuum chamber has been proposed in the literature, but the improvement of ion transmission efficiency is limited. To improve ion transmission, in this study we propose a novel method using a home-made golf ball positioned between the ion source and the inlet of the mass analyzer to hydrodynamically focus the ions passing through the golf ball. The ion plume produced by the ESI process passes through the golf ball will reduce the size of the ion cloud then be focused and most of them flowed into the mass analyzer. Therefore, the sensitivity will be improved, the aim of this investigation is to study the enhancing of the signal using golf ball-assisted electrospray ionization liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine 20 trace amino acids in complex samples, including tea, urine and serum. The results showed that the analytical performance of the determination of the 20 amino acids in tea, urine and serum samples using the home-made golf ball-assisted ESI source is better than that of a commercial ESI source. The signal intensities of the 20 amino acids were enhanced by factors of 2-2700, 11-2525, and 31-342680 in oolong tea, urine and serum analyses, respectively. The precision of the proposed method ranged from 1-9%, 0.4-9% and 0.4-8% at low, medium and high concentration levels of amino acids, respectively. The home-made golf ball-assisted ESI source effectively increased the signal intensity and enhanced the ion transmission efficiency and is also an easy, convenient and economical device. This technique can be applied to the analysis of trace compounds in complex matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

Proceedings of the 10th international workshop on ECR ion sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, F W; Kirkpatrick, M I

This report contains papers on the following topics: Recent Developments and Future Projects on ECR Ion Sources; Operation of the New KVI ECR Ion Source at 10 GHz; Operational Experience and Status of the INS SF-ECR Ion Source; Results of the New ECR4'' 14.5 GHz ECRIS; Preliminary Performance of the AECR; Experimental Study of the Parallel and Perpendicular Particle Losses from an ECRIS Plasma; Plasma Instability in Electron Cyclotron Resonance Heated Ion Sources; The Hyperbolic Energy Analyzer; Status of ECR Source Development; The New 10 GHz CAPRICE Source; First Operation of the Texas A M ECR Ion Source; Recent Developmentsmore » of the RIKEN ECR Ion Sources; The 14 GHz CAPRICE Source; Characteristics and Potential Applications of an ORNL Microwave ECR Multicusp Plasma Ion Source; ECRIPAC: The Production and Acceleration of Multiply Charged Ions Using an ECR Plasma; ECR Source for the HHIRF Tandem Accelerator; Feasibility Studies for an ECR-Generated Plasma Stripper; Production of Ion Beams by using the ECR Plasmas Cathode; A Single Stage ECR Source for Efficient Production of Radioactive Ion Beams; The Single Staged ECR Source at the TRIUMF Isotope Separator TISOL; The Continuous Wave, Optically Pumped H{sup {minus}} Source; The H{sup +} ECR Source for the LAMPF Optically Pumped Polarized Ion Source; Present Status of the Warsaw CUSP ECR Ion Source; An ECR Source for Negative Ion Production; GYRAC-D: A Device for a 200 keV ECR Plasma Production and Accumulation; Status Report of the 14.4 GHZ ECR in Legnaro; Status of JYFL-ECRIS; Report on the Uppsala ECRIS Facility and Its Planned Use for Atomic Physics; A 10 GHz ECR Ion Source for Ion-Electron and Ion-Atom Collision Studies; and Status of the ORNL ECR Source Facility for Multicharged Ion Collision Research.« less

SU-E-T-758: To Determine the Source Dwell Positions of HDR Brachytherapy Using 2D 729 Ion Chamber Array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Syam; Sitha

2015-06-15

Purpose: Determination of source dwell positions of HDR brachytherapy using 2D 729 ion chamber array Methods: Nucletron microselectron HDR and PTW 2D array were used for the study. Different dwell positions were assigned in the HDR machine. Rigid interstitial needles and vaginal applicator were positioned on the 2D array. The 2D array was exposed for this programmed dwell positions. The positional accuracy of the source was analyzed after the irradiation of the 2D array. This was repeated for different dwell positions. Different test plans were transferred from the Oncentra planning system and irradiated with the same applicator position on themore » 2D array. The results were analyzed using the in house developed excel program. Results: Assigned dwell positions versus corresponding detector response were analyzed. The results show very good agreement with the film measurements. No significant variation found between the planned and measured dwell positions. Average dose response with 2D array between the planned and nearby dwell positions was found to be 0.0804 Gy for vaginal cylinder applicator and 0.1234 Gy for interstitial rigid needles. Standard deviation between the doses for all the measured dwell positions for interstitial rigid needle for 1 cm spaced positions were found to be 0.33 and 0.37 for 2cm spaced dwell positions. For intracavitory vaginal applicator this was found to be 0.21 for 1 cm spaced dwell positions and 0.06 for 2cm spaced dwell positions. Intracavitory test plans reproduced on the 2D array with the same applicator positions shows the ideal dose distribution with the TPS planned. Conclusion: 2D array is a good tool for determining the dwell position of HDR brachytherapy. With the in-house developed program in excel it is easy and accurate. The traditional way with film analysis can be replaced by this method, as the films will be more costly.« less

Design of the low energy beam transport line for the China spallation neutron source

NASA Astrophysics Data System (ADS)

Li, Jin-Hai; Ouyang, Hua-Fu; Fu, Shi-Nian; Zhang, Hua-Shun; He, Wei

2008-03-01

The design of the China Spallation Neutron Source (CSNS) low-energy beam transport (LEBT) line, which locates between the ion source and the radio-frequency quadrupole (RFQ), has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74 m. This LEBT is designed to transfer 20 mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper. The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.

On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

NASA Astrophysics Data System (ADS)

Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Fantz, U.; Franzen, P.; Minea, T.

2014-10-01

The development of a large area (Asource,ITER = 0.9 × 2 m2) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (Asource,BATMAN ≈ 0.32 × 0.59 m2) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child-Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion-ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated extracted currents, both ions and electrons, agree rather well with the experiment.

Mechanistic Study of the Gas-Phase In-Source Hofmann Elimination of Doubly Quaternized Cinchona-Alkaloid Based Phase-Transfer Catalysts by (+)-Electrospray Ionization/Tandem Mass Spectrometry.

PubMed

Yang, Rong-Sheng; Sheng, Huaming; Lexa, Katrina W; Sherer, Edward C; Zhang, Li-Kang; Xiang, Bangping; Helmy, Roy; Mao, Bing

2017-03-01

An unusual in-source fragmentation pattern observed for 14 doubly quaternized cinchona alkaloid-based phase-transfer catalysts (PTC) was studied using (+)-ESI high resolution mass spectrometry. Loss of the substituted benzyl cation (R1 or R2) was found to be the major product ion [M 2+ - R 1 + or R 2 + ] + in MS spectra of all PTC compounds. A Hofmann elimination product ion [M - H] + was also observed. Only a small amount of the doubly charged M 2+ ions were observed in the MS spectra, likely due to strong Columbic repulsion between the two quaternary ammonium cations in the gas phase. The positive voltage in the MS inlet but not the ESI probe was found to induce this extensive fragmentation for all PTC diboromo-salts. Compound 1 was used as an example to illustrate the proposed in-source fragmentation mechanism. The mechanism of formation of the Hofmann elimination product ion [M - H] + was further investigated using HRMS/MS, H/D exchange, and DFT calculations. The proposed formation of 2b as the major Hofmann elimination product ion was supported both by HRMS/MS and DFT calculations. Formation of product ion 2b through a concerted unimolecular E i elimination pathway is proposed rather than a bimolecular E2 elimination pathway for common solution Hofmann eliminations. Graphical Abstract ᅟ.

Mechanistic Study of the Gas-Phase In-Source Hofmann Elimination of Doubly Quaternized Cinchona-Alkaloid Based Phase-Transfer Catalysts by (+)-Electrospray Ionization/Tandem Mass Spectrometry

NASA Astrophysics Data System (ADS)

Yang, Rong-Sheng; Sheng, Huaming; Lexa, Katrina W.; Sherer, Edward C.; Zhang, Li-Kang; Xiang, Bangping; Helmy, Roy; Mao, Bing

2017-03-01

An unusual in-source fragmentation pattern observed for 14 doubly quaternized cinchona alkaloid-based phase-transfer catalysts (PTC) was studied using (+)-ESI high resolution mass spectrometry. Loss of the substituted benzyl cation (R1 or R2) was found to be the major product ion [M2+ - R1 + or R2 +]+ in MS spectra of all PTC compounds. A Hofmann elimination product ion [M - H]+ was also observed. Only a small amount of the doubly charged M2+ ions were observed in the MS spectra, likely due to strong Columbic repulsion between the two quaternary ammonium cations in the gas phase. The positive voltage in the MS inlet but not the ESI probe was found to induce this extensive fragmentation for all PTC diboromo-salts. Compound 1 was used as an example to illustrate the proposed in-source fragmentation mechanism. The mechanism of formation of the Hofmann elimination product ion [M - H]+ was further investigated using HRMS/MS, H/D exchange, and DFT calculations. The proposed formation of 2b as the major Hofmann elimination product ion was supported both by HRMS/MS and DFT calculations. Formation of product ion 2b through a concerted unimolecular Ei elimination pathway is proposed rather than a bimolecular E2 elimination pathway for common solution Hofmann eliminations.

Study of mechanism of stress-induced threshold voltage shift and recovery in top-gate amorphous-InGaZnO4 thin-film transistors with source- and drain-offsets

NASA Astrophysics Data System (ADS)

Mativenga, Mallory; Kang, Dong Han; Lee, Ung Gi; Jang, Jin

2012-09-01

Bias instability of top-gate amorphous-indium-gallium-zinc-oxide thin-film transistors with source- and drain-offsets is reported. Positive and negative gate bias-stress (VG_STRESS) respectively induce reversible negative threshold-voltage shift (ΔVTH) and reduction in on-current. Migration of positive charges towards the offsets lowers the local resistance of the offsets, resulting in the abnormal negative ΔVTH under positive VG_STRESS. The reduction in on-current under negative VG_STRESS is due to increase in resistance of the offsets when positive charges migrate away from the offsets. Appropriate drain and source bias-stresses applied simultaneously with VG_STRESS either suppress or enhance the instability, verifying lateral ion migration to be the instability mechanism.

Numerical Model of the Plasma Sheath Generated by the Plasma Source Instrument Aboard the Polar Satellite

NASA Technical Reports Server (NTRS)

Leung, Wing C.; Singh, Nagendra; Moore, Thomas E.; Craven, Paul D.

2000-01-01

The plasma sheath generated by the operation of the Plasma Source Instrument (PSI) aboard the POLAR satellite is studied by using a 3-dimensional Particle-In-Cell (PIC) code. When the satellite passes through the region of low density plasma, the satellite charges to positive potentials as high as 4050Volts due to the photoelectrons emission. In such a case, ambient core ions cannot accurately be measured or detected. The goal of the onboard PSI is to reduce the floating potential of the satellite to a sufficiently low value so that the ions in the polar wind become detectable. When the PSI is operated, an ion-rich Xenon plasma is ejected from the satellite, such that the floating potential of the satellite is reduced and is maintained at about 2Volts. Accordingly, in our 3-dimensional PIC simulation, we considered that the potential of the satellite is 2Volts as a fixed bias. Considering the relatively high density of the Xenon plasma in the sheath (approx. 10 - 10(exp 3)/cc), the ambient plasma of low density (less than 1/cc) is neglected. In the simulations, the electric fields and plasma dynamics are calculated self-consistently. We found that an "Apple" shape positive potential sheath forms surrounding the satellite. In the region near the PSI emission, a high positive potential hill develops. Near the Thermal Ion Detection Experiment (TIDE) detector away from the PSI, the potentials are sufficiently low for the ambient polar wind ions to reach it. In the simulations, it takes about a hundred electron gyroperiods for the sheath to reach a quasi-steady state. This time is approximately the time taken by the heavy Xe(+) ions to expand up to about one average Larmor radius of electrons from the satellite surface. Using the steady state sheath, we performed trajectory calculations to characterize the detector response to a highly supersonic polar wind flow. The detected ions' velocity distribution shows significant deviations from a shifted Maxwellian in the ambient polar wind population. The deviations are caused by the effects of electric fields on the ions' motion as they traverse the sheath.

Effect of a metal-dielectric structure introduced in the plasma chamber of the Frankfurt 14 GHz electron cyclotron resonance ion source

NASA Astrophysics Data System (ADS)

Schächter, L.; Stiebing, K. E.; Dobrescu, S.; Badescu-Singureanu, Al. I.; Schmidt, L.; Hohn, O.; Runkel, S.

1999-02-01

A new approach of the possibility to significantly increase the high charge state ion beams delivered by electron cyclotron resonance (ECR) ion sources by using metal-dielectric (MD) structures characterized by high secondary electron emission properties is presented. The intensities of argon ion beams extracted from the 14 GHz electron cyclotron resonance ion source of the Institut für Kernphysik (IKF) der Johann Wolfgang Goethe-Universität in Frankfurt/Main were measured when a 26 mm diam disk of a specially treated MD structure (Al-Al2O3) was introduced axially close to the ECR plasma. The Ar beam intensities and charge-state distributions obtained with this disk are compared to measurements with disks of iron and pure aluminum at the same position relative to the plasma. All measurements were performed with the disk at the plasma chamber potential. The results with the MD structure show a net shift of the beam intensity towards higher charge states as compared with the other disk materials. Enhancement factors of the beam current of up to 10 (for Ar12+) when using a MD disk compared to the output when using an aluminum disk and up to 40 (for Ar11+) when using an iron disk were measured.

A multicentre audit of HDR/PDR brachytherapy absolute dosimetry in association with the INTERLACE trial (NCT015662405)

NASA Astrophysics Data System (ADS)

Díez, P.; Aird, E. G. A.; Sander, T.; Gouldstone, C. A.; Sharpe, P. H. G.; Lee, C. D.; Lowe, G.; Thomas, R. A. S.; Simnor, T.; Bownes, P.; Bidmead, M.; Gandon, L.; Eaton, D.; Palmer, A. L.

2017-12-01

A UK multicentre audit to evaluate HDR and PDR brachytherapy has been performed using alanine absolute dosimetry. This is the first national UK audit performing an absolute dose measurement at a clinically relevant distance (20 mm) from the source. It was performed in both INTERLACE (a phase III multicentre trial in cervical cancer) and non-INTERLACE brachytherapy centres treating gynaecological tumours. Forty-seven UK centres (including the National Physical Laboratory) were visited. A simulated line source was generated within each centre’s treatment planning system and dwell times calculated to deliver 10 Gy at 20 mm from the midpoint of the central dwell (representative of Point A of the Manchester system). The line source was delivered in a water-equivalent plastic phantom (Barts Solid Water) encased in blocks of PMMA (polymethyl methacrylate) and charge measured with an ion chamber at 3 positions (120° apart, 20 mm from the source). Absorbed dose was then measured with alanine at the same positions and averaged to reduce source positional uncertainties. Charge was also measured at 50 mm from the source (representative of Point B of the Manchester system). Source types included 46 HDR and PDR 192Ir sources, (7 Flexisource, 24 mHDR-v2, 12 GammaMed HDR Plus, 2 GammaMed PDR Plus, 1 VS2000) and 1 HDR 60Co source, (Co0.A86). Alanine measurements when compared to the centres’ calculated dose showed a mean difference (±SD) of  +1.1% (±1.4%) at 20 mm. Differences were also observed between source types and dose calculation algorithm. Ion chamber measurements demonstrated significant discrepancies between the three holes mainly due to positional variation of the source within the catheter (0.4%-4.9% maximum difference between two holes). This comprehensive audit of absolute dose to water from a simulated line source showed all centres could deliver the prescribed dose to within 5% maximum difference between measurement and calculation.

The charge spectrum of positive ions in a hydrogen aurora

NASA Technical Reports Server (NTRS)

Lynch, J.; Pulliam, D.; Leach, R.; Scherb, F.

1976-01-01

An auroral ion charge spectrometer was flown into a hydrogen aurora on a Javelin sounding rocket launched from Churchill, Manitoba. The instrument contained an electrostatic analyzer which selected particles with incident energy per unit charge up to 20 keV/charge and an 80-kV power supply which accelerated these ions onto an array of solid state detectors. Ions tentatively identified as H(+), He(+2), and O(+) were detected from 225 to 820 km in altitude. The experiment did not discriminate between H(+) and He(+), or between O(+), N(+), and C(+). Upper limits of highly charged heavy ion abundances have been set at 20% of the He(+2) and 0.15% of the H(+). It is concluded that both terrestrial and solar wind sources play significant roles in auroral ion precipitation.

Peroxide Bond Driven Dissociation of Hydroperoxy-Cholesterol Esters Following Collision Induced Dissociation

NASA Astrophysics Data System (ADS)

Hutchins, Patrick M.; Murphy, Robert C.

2011-05-01

Oxidative modification of polyunsaturated fatty acids, which occurs through enzymatic and nonenzymatic processes, is typically initiated by the attachment of molecular oxygen to an unsaturated fatty acyl chain forming a lipid hydroperoxide (LOOH). Enzymatic pathways are critical for cellular homeostasis but aberrant lipid peroxidation has been implicated in important pathologies. Analysis of primary oxidation products such as hydroperoxides has proven to be challenging for a variety of reasons. While negative ion electrospray ionization has been used for the specific detection of some LOOH species, hydroperoxide dehydration in the ion source has been a significant drawback. Here we describe positive ion electrospray ionization of ammoniated 13-hydroperoxy-9Z, 11E-octadecadienoyl cholesterol and 9-hydroperoxy-10E, 12Z-octadecadienoyl cholesterol, [M + NH4]+, following normal phase high-pressure liquid-chromatography. Dehydration in the ion source was not prevalent and the ammoniated molecular ion was the major species observed. Collisionally induced dissociation of the two positional isomers yielded unique product ion spectra resulting from carbon-carbon cleavages along their acyl chains. Further investigation of this behavior revealed that complex collision induced dissociations were initiated by scission of the hydroperoxide bond that drove subsequent acyl chain cleavages. Interestingly, some of the product ions retained the ammonium nitrogen through the formation of covalent carbon-nitrogen or oxygen-nitrogen bonds. These studies were carried out using hydroperoxy-octadecadienoate cholesteryl esters as model compounds, however the observed mechanisms of [LOOH + NH4]+ ionization and dissociation are likely applicable to the analysis of other lipid hydroperoxides and may serve as the basis for selective LOOH detection as well as aid in the identification of unknown lipid hydroperoxides.

Design and Preliminary Performance Testing of Electronegative Gas Plasma Thruster

NASA Technical Reports Server (NTRS)

Liu, Thomas M.; Schloeder, Natalie R.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.; Aanesland, Ane

2014-01-01

In classical gridded electrostatic ion thrusters, positively charged ions are generated from a plasma discharge of noble gas propellant and accelerated to provide thrust. To maintain overall charge balance on the propulsion system, a separate electron source is required to neutralize the ion beam as it exits the thruster. However, if high-electronegativity propellant gases (e.g., sulfur hexafluoride) are instead used, a plasma discharge can result consisting of both positively and negatively charged ions. Extracting such electronegative plasma species for thrust generation (e.g., with time-varying, bipolar ion optics) would eliminate the need for a separate neutralizer cathode subsystem. In addition for thrusters utilizing a RF plasma discharge, further simplification of the ion thruster power system may be possible by also using the RF power supply to bias the ion optics. Recently, the PEGASES (Plasma propulsion with Electronegative gases) thruster prototype successfully demonstrated proof-of-concept operations in alternatively accelerating positively and negatively charged ions from a RF discharge of a mixture of argon and sulfur hexafluoride.i In collaboration with NASA Marshall Space Flight Center (MSFC), the Georgia Institute of Technology High-Power Electric Propulsion Laboratory (HPEPL) is applying the lessons learned from PEGASES design and testing to develop a new thruster prototype. This prototype will incorporate design improvements and undergo gridless operational testing and diagnostics checkout at HPEPL in April 2014. Performance mapping with ion optics will be conducted at NASA MSFC starting in May 2014. The proposed paper discusses the design and preliminary performance testing of this electronegative gas plasma thruster prototype.

Isotope separation by selective charge conversion and field deflection

DOEpatents

Hickman, Robert G.

1978-01-01

A deuterium-tritium separation system wherein a source beam comprised of positively ionized deuterium (D.sup.+) and tritium (T.sup.+) is converted at different charge-exchange cell sections of the system to negatively ionized deuterium (D.sup.-) and tritium (T.sup.-). First, energy is added to the beam to accelerate the D.sup.+ ions to the velocity that is optimum for conversion of the D.sup.+ ions to D.sup.- ions in a charge-exchange cell. The T.sup.+ ions are accelerated at the same time, but not to the optimum velocity since they are heavier than the D.sup.+ ions. The T.sup.+ ions are, therefore, not converted to T.sup.- ions when the D.sup.+ ions are converted to D.sup.- ions. This enables effective separation of the beam by deflection of the isotopes with an electrostatic field, the D.sup.- ions being deflected in one direction and the T.sup.+ ions being deflected in the opposite direction. Next, more energy is added to the deflected beam of T.sup.+ ions to bring the T.sup.+ ions to the optimum velocity for their conversion to T.sup.- ions. In a particular use of the invention, the beams of D.sup.- and T.sup.- ions are separately further accelerated and then converted to energetic neutral particles for injection as fuel into a thermonuclear reactor. The reactor exhaust of D.sup.+ and T.sup.+ and the D.sup.+ and T.sup.+ that was not converted in the respective sections is combined with the source beam and recycled through the system to increase the efficiency of the system.

Corona discharge ionization of paracetamol molecule: Peak assignment

NASA Astrophysics Data System (ADS)

Bahrami, H.; Farrokhpour, H.

2015-01-01

Ionization of paracetamol was investigated using ion mobility spectrometry equipped with a corona discharge ionization source. The measurements were performed in the positive ion mode and three peaks were observed in the ion mobility spectrum. Experimental evidence and theoretical calculations were used to correlate the peaks to related ionic species of paracetamol. Two peaks were attributed to protonated isomers of paracetamol and the other peak was attributed to paracetamol fragment ions formed by dissociation of the N-C bond after protonation of the nitrogen atom. It was observed that three sites of paracetamol compete for protonation and their relative intensities, depending on the sample concentration. The ratio of ion products could be predicted from the internal proton affinity of the protonation sites at each concentration.

Penning discharge ion source with self-cleaning aperture

DOEpatents

Gavin, Basil F.; MacGill, Robert A.; Thatcher, Raymond K.

1982-01-01

An ion source of the Penning discharge type having a self-cleaning aperture is provided by a second dynode (24) with an exit aperture (12) in a position opposite a first dynode 10a, from which the ions are sputtered, two opposing cathodes (14, 16), each with an anode (18, 20) for accelerating electrons emitted from the cathodes into a cylindrical space defined by the first and second dynode. A support gas maintained in this space is ionized by the electrons. While the cathodes are supplied with a negative pulse to emit electrons, the first dynode is supplied with a negative pulse (e.g., -300 V) to attract atoms of the ionized gas (plasma). At the same time, the second dynode may also be supplied with a small voltage that is negative with respect to the plasma (e.g., -5 V) for tuning the position of the plasma miniscus for optimum extraction geometry. When the negative pulse to the first dynode is terminated, the second dynode is driven strongly negative (e.g., -600 V) thereby allowing heavy sputtering to take place for a short period to remove virtually all of the atoms deposited on the second dynode from material sputtered off the first dynode. An extractor (22) immediately outside the exit aperture of the second dynode is maintained at ground potential during this entire period of sputtering while the anode, dynode and cathode reference voltage is driven strongly positive (about +20 kV to +30 kV) so that ions accelerated through the aperture will be at ground potential. In that manner, material from the first dynode deposited on the second dynode will be sputtered, in time, to add to the ion beam. Atoms sputtered from the second dynode which do not become ionized and exit through the slit will be redeposited on the first dynode, and hence recycled for further ion beam generation during subsequent operating cycles.

Investigation of radiofrequency plasma sources for space travel

NASA Astrophysics Data System (ADS)

Charles, C.; Boswell, R. W.; Takahashi, K.

2012-12-01

Optimization of radiofrequency (RF) plasma sources for the development of space thrusters differs from other applications such as plasma processing of materials since power efficiency, propellant usage, particle acceleration or heating become driving parameters. The development of two RF (13.56 MHz) plasma sources, the high-pressure (˜1 Torr) capacitively coupled ‘pocket rocket’ plasma micro-thruster and the low-pressure (˜1 mTorr) inductively coupled helicon double layer thruster (HDLT), is discussed within the context of mature and emerging electric propulsion devices. The density gradient in low-pressure expanding RF plasmas creates an electric field that accelerates positive ions out of the plasma. Generally, the total potential drop is similar to that of a wall sheath allowing the plasma electrons to neutralize the ion beam. A high-pressure expansion with no applied magnetic field can result in large dissociation rates and/or a collimated beam of ions of small area and a flowing heated neutral beam (‘pocket rocket’). A low-pressure expansion dominated by a magnetic field can result in the formation of electric double layers which produce a very directed neutralized beam of ions of large area (HDLT).

Energy deposition rates by charged particles. [in upper atmosphere

NASA Technical Reports Server (NTRS)

Torkar, K. M.; Urban, A.; Bjordal, J.; Lundblad, J. A.; Soraas, F.; Smith, L. G.; Dumbs, A.; Grandal, B.; Ulwick, J. C.; Vancour, R. P.

1985-01-01

A summary of measurements of the precipitation of electrons and positive ions (in the keV-MeV range) detected aboard eight rockets launched within the Energy Budget Campaign from Northern Scandinavia is given, together with corresponding satellite data. In some cases strong temporal variations of the downgoing integral fluxes were observed. The fluxes provide the background for the calculated ion production rates and altitude profiles of the energy deposition into the atmosphere at different levels of geomagnetic disturbance and cosmic noise absorption. The derived ion production rates by eneretic particles are compared to other night-time ionisation sources.

Plasma-surface interaction in negative hydrogen ion sources

NASA Astrophysics Data System (ADS)

Wada, Motoi

2018-05-01

A negative hydrogen ion source delivers more beam current when Cs is introduced to the discharge, but a continuous operation of the source reduces the beam current until more Cs is added to the source. This behavior can be explained by adsorption and ion induced desorption of Cs atoms on the plasma grid surface of the ion source. The interaction between the ion source plasma and the plasma grid surface of a negative hydrogen ion source is discussed in correlation to the Cs consumption of the ion source. The results show that operation with deuterium instead of hydrogen should require more Cs consumption and the presence of medium mass impurities as well as ions of the source wall materials in the arc discharge enlarges the Cs removal rate during an ion source discharge.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, N.C.; Limbach, P.A.; Shomo, R.E. II

The coupling of an autoneutralizing SF{sup {minus}}{sub 6} fast ion-beam gun to a Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometer is described. The fast neutral beam provides for secondary-ion-type FT/ICR mass analysis (e.g., production of abundant pseudomolecular (M+H){sup +} ions) of involatile samples without the need for external ion injection, since ions are formed at the entrance to the ICR ion trap. The design, construction, and testing of the hybrid instrument are described. The feasibility of the experiment (for both broadband and high-resolution FT/ICR positive-ion mass spectra) is demonstrated with {ital tetra}-butylammonium bromide and a Tylenol{sup ( )} sample.more » The ability to analyze high molecular weight polymers with high mass resolution is demonstrated for Teflon{sup ( )}. All of the advantages of the fast neutral beam ion source previously demonstrated with quadrupole mass analysis are preserved, and the additional advantages of FT/ICR mass analysis (e.g., high mass resolving power, ion trapping) are retained.« less

A singly charged ion source for radioactive {sup 11}C ion acceleration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katagiri, K.; Noda, A.; Nagatsu, K.

2016-02-15

A new singly charged ion source using electron impact ionization has been developed to realize an isotope separation on-line system for simultaneous positron emission tomography imaging and heavy-ion cancer therapy using radioactive {sup 11}C ion beams. Low-energy electron beams are used in the electron impact ion source to produce singly charged ions. Ionization efficiency was calculated in order to decide the geometric parameters of the ion source and to determine the required electron emission current for obtaining high ionization efficiency. Based on these considerations, the singly charged ion source was designed and fabricated. In testing, the fabricated ion source wasmore » found to have favorable performance as a singly charged ion source.« less

3D numerical simulations of negative hydrogen ion extraction using realistic plasma parameters, geometry of the extraction aperture and full 3D magnetic field map

NASA Astrophysics Data System (ADS)

Mochalskyy, S.; Wünderlich, D.; Ruf, B.; Franzen, P.; Fantz, U.; Minea, T.

2014-02-01

Decreasing the co-extracted electron current while simultaneously keeping negative ion (NI) current sufficiently high is a crucial issue on the development plasma source system for ITER Neutral Beam Injector. To support finding the best extraction conditions the 3D Particle-in-Cell Monte Carlo Collision electrostatic code ONIX (Orsay Negative Ion eXtraction) has been developed. Close collaboration with experiments and other numerical models allows performing realistic simulations with relevant input parameters: plasma properties, geometry of the extraction aperture, full 3D magnetic field map, etc. For the first time ONIX has been benchmarked with commercial positive ions tracing code KOBRA3D. A very good agreement in terms of the meniscus position and depth has been found. Simulation of NI extraction with different e/NI ratio in bulk plasma shows high relevance of the direct negative ion extraction from the surface produced NI in order to obtain extracted NI current as in the experimental results from BATMAN testbed.

Ion acoustic shock wave in collisional equal mass plasma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adak, Ashish, E-mail: ashish-adak@yahoo.com; Ghosh, Samiran, E-mail: sran-g@yahoo.com; Chakrabarti, Nikhil, E-mail: nikhil.chakrabarti@saha.ac.in

The effect of ion-ion collision on the dynamics of nonlinear ion acoustic wave in an unmagnetized pair-ion plasma has been investigated. The two-fluid model has been used to describe the dynamics of both positive and negative ions with equal masses. It is well known that in the dynamics of the weakly nonlinear wave, the viscosity mediates wave dissipation in presence of weak nonlinearity and dispersion. This dissipation is responsible for the shock structures in pair-ion plasma. Here, it has been shown that the ion-ion collision in presence of collective phenomena mediated by the plasma current is the source of dissipationmore » that causes the Burgers' term which is responsible for the shock structures in equal mass pair-ion plasma. The dynamics of the weakly nonlinear wave is governed by the Korteweg-de Vries Burgers equation. The analytical and numerical investigations revealed that the ion acoustic wave exhibits both oscillatory and monotonic shock structures depending on the frequency of ion-ion collision parameter. The results have been discussed in the context of the fullerene pair-ion plasma experiments.« less

Comparison of reactant and analyte ions for ⁶³Nickel, corona discharge, and secondary electrospray ionization sources with ion mobility-mass spectrometry.

PubMed

Crawford, C L; Hill, H H

2013-03-30

(63)Nickel radioactive ionization ((63)Ni) is the most common and widely used ion source for ion mobility spectrometry (IMS). Regulatory, financial, and operational concerns with this source have promoted recent development of non-radioactive sources, such as corona discharge ionization (CD), for stand-alone IMS systems. However, there has been no comparison of the negative ion species produced by all three sources in the literature. This study compares the negative reactant and analyte ions produced by three sources on an ion mobility-mass spectrometer: conventional (63)Ni, CD, and secondary electrospray ionization (SESI). Results showed that (63)Ni and SESI produced the same reactant ion species while CD produced only the nitrate monomer and dimer ions. The analyte ions produced by each ion source were the same except for the CD source which produced a different ion species for the explosive RDX than either the (63)Ni or SESI source. Accurate and reproducible reduced mobility (K0) values, including several values reported here for the first time, were found for each explosive with each ion source. Overall, the SESI source most closely reproduced the reactant ion species and analyte ion species profiles for (63)Ni. This source may serve as a non-radioactive, robust, and flexible alternative for (63)Ni. Copyright © 2013 Elsevier B.V. All rights reserved.

Ion Storage Tests with the High Performance Antimatter Trap (HiPAT)

NASA Technical Reports Server (NTRS)

Martin, James J.; Lewis, Raymond A.; Chakrabarti, Suman; Pearson, Boise; Schafer, Charles (Technical Monitor)

2002-01-01

The NASA/Marshall Space Flight Centers (NASA/MSFC) Propulsion Research Center (PRC) is evaluating an antiproton storage system, referred to as the High Performance Antiproton Trap (HiPAT). This interest stems from the sheer energy represented by matter/antimatter annihilation process with has an energy density approximately 10 order of magnitude above that of chemical propellants. In other terms, one gram of antiprotons contains the equivalent energy of approximately 23 space shuttle external tanks or ET's (each ET contains roughly 740,000 kgs of fuel and oxidizer). This incredible source of stored energy, if harnessed, would be an enabling technology for deep space mission where both spacecraft weight and propulsion performance are key to satisfying aggressive mission requirements. The HiPAT hardware consists of a 4 Tesla superconductor system, an ultra high vacuum test section (vacuum approaching 10(exp -12) torr), and a high voltage confinement electrode system (up to 20 kvolts operation). The current laboratory layout is illustrated. The HiPAT designed objectives included storage of up to 1 trillion antiprotons with corresponding lifetimes approaching 18 days. To date, testing has centered on the storage of positive hydrogen ions produced in situ by a stream of high-energy electrons that passes through the trapping region. However, due to space charge issues and electron beam compression as it passes through the HiPAT central field, current ion production is limited to less then 50,000 ions. Ion lifetime was determined by counting particle populations at the end of various storage time intervals. Particle detection was accomplished by destructively expelling the ions against a micro-channel plate located just outside the traps magnetic field. The effect of radio frequency (RF) stabilization on the lifetime of trapped particles was also examined. This technique, referred to as a rotating wall, made use of a segmented electrode located near the center of the trap on which various phases of a particular frequency were applied. Various experiments were performed illustrating the ability of an RF drive to both prolong and reduced the lifetimes of various ion species depending on the selected frequency. HiPAT is now being reconfigured for testing with an ion source that will provide both positive and negative hydrogen ions from an external source. This ion system shall provide higher fill capacity (order of million of ions per shot), stacking of multiple shots, and injection schemes typical of a realistic antiproton delivery system.

Measurements of the energy distribution of a high brightness rubidium ion beam.

PubMed

Ten Haaf, G; Wouters, S H W; Nijhof, D F J; Mutsaers, P H A; Vredenbregt, E J D

2018-07-01

The energy distribution of a high brightness rubidium ion beam, which is intended to be used as the source for a focused ion beam instrument, is measured with a retarding field analyzer. The ions are created from a laser-cooled and compressed atomic beam by two-step photoionization in which the ionization laser power is enhanced in a build-up cavity. Particle tracing simulations are performed to ensure the analyzer is able to resolve the distribution. The lowest achieved full width 50% energy spread is (0.205 ± 0.006) eV, which is measured at a beam current of 9 pA. The energy spread originates from the variation in the ionization position of the ions which are created inside an extraction electric field. This extraction field is essential to limit disorder-induced heating which can decrease the ion beam brightness. The ionization position distribution is limited by a tightly focused excitation laser beam. Energy distributions are measured for various ionization and excitation laser intensities and compared with calculations based on numerical solutions of the optical Bloch equations including ionization. A good agreement is found between measurements and calculations. Copyright © 2018 Elsevier B.V. All rights reserved.

Particle-in-cell simulations of bounded plasma discharges applied to low pressure high density sources and positive columns

NASA Astrophysics Data System (ADS)

Kawamura, Emi

Particle-in-cell (PIC) simulations of bounded plasma discharges are attractive because the fields and the particle motion can be obtained self-consistently from first principles. Thus, we can accurately model a wide range of nonlocal and kinetic behavior. The only disadvantage is that PIC may be computationally expensive compared to other methods. Fluid codes, for example, may run faster but make assumptions about the bulk plasma velocity distributions and ignore kinetic effects. In Chapter 1, we demonstrate methods of accelerating PIC simulations of bounded plasma discharges. We find that a combination of physical and numerical methods makes run-times for PIC codes much more competitive with other types of codes. In processing plasmas, the ion energy distributions (IEDs) arriving at the wafer target are crucial in determining ion anisotropy and etch rates. The current trend for plasma reactors is towards lower gas pressure and higher plasma density. In Chapter 2, we review and analyze IEDs arriving at the target of low pressure high density rf plasma reactors. In these reactors, the sheath is typically collisionless. We then perform PIC simulations of collisionless rf sheaths and find that the key parameter governing the shape of the TED at the wafer is the ratio of the ion transit time across the sheath over the rf period. Positive columns are the source of illumination in fluorescent mercury-argon lamps. The efficiency of light production increases with decreasing gas pressure and decreasing discharge radius. Most current lamp software is based on the local concept even though low pressure lighting discharges tend to be nonlocal. In Chapter 3, we demonstrate a 1d3v radial PIC model to conduct nonlocal kinetic simulations of low pressure, small radius positive columns. When compared to other available codes, we find that our PIC code makes the least approximations and assumptions and is accurate and stable over a wider parameter range. We analyze the PIC simulation results in detail and find that the radial electron heat flow, which is neglected in local models, plays a major role in maintaining the global power balance. In Chapter 2, we focused on the sheaths of low pressure high density plasma reactors. In Chapter 4, we extend our study to the bulk and presheaths. Typical industrial plasma reactors often use gases with complex chemistries which tend to generate discharges containing negative ions. For high density electronegative plasmas with low gas pressure, we expect Coulomb collisions between positive and negative ions to dominate over collisions between ions and neutrals. We incorporate a Coulomb collision model into our PIC code to study the effect of this ion-ion Coulomb scattering. We find that the Coulomb collisions between the positive and negative ions significantly modify the negative ion flux, density and kinetic energy profiles.

Precise Determination of the Lyman-1 Transition Energy in Hydrogen-like Gold Ions with Microcalorimeters

NASA Astrophysics Data System (ADS)

Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Grabitz, P.; Kilbourne, C.; Kiselev, O.; McCammon, D.; Scholz, P.

2014-09-01

The precise determination of the transition energy of the Lyman-1 line in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. We report the determination of the Lyman-1 transition energy of gold ions (Au) with microcalorimeters at the experimental storage ring at GSI. X-rays produced by the interaction of 125 MeV/u Au ions with an internal argon gas-jet target were detected. The detector array consisted of 14 pixels with silicon thermistors and Sn absorbers, for which an energy resolution of 50 eV for an X-ray energy of 59.5 keV was obtained in the laboratory. The Lyman-1 transition energy was determined for each pixel in the laboratory frame, then transformed into the emitter frame and averaged. A Dy-159 source was used for energy calibration. The absolute positions of the detector pixels, which are needed for an accurate correction of the Doppler shift, were determined by topographic measurements and by scanning a collimated Am-241 source across the cryostat window. The energy of the Lyman-1 line in the emitter frame is eV, in good agreement with theoretical predictions. The systematic error is dominated by the uncertainty in the position of the cryostat relative to the interaction region of beam and target.

Laser ion source for high brightness heavy ion beam

DOE PAGES

Okamura, M.

2016-09-01

A laser ion source is known as a high current high charge state heavy ion source. But, we place great emphasis on the capability to realize a high brightness ion source. A laser ion source has a pinpoint small volume where materials are ionized and can achieve quite uniform low temperature ion beam. Those features may enable us to realize very small emittance beams. Furthermore, a low charge state high brightness laser ion source was successfully commissioned in Brookhaven National Laboratory in 2014. Now most of all the solid based heavy ions are being provided from the laser ion sourcemore » for regular operation.« less

Time-resolved imaging of the MALDI linear-TOF ion cloud: direct visualization and exploitation of ion optical phenomena using a position- and time-sensitive detector.

PubMed

Ellis, Shane R; Soltwisch, Jens; Heeren, Ron M A

2014-05-01

In this study, we describe the implementation of a position- and time-sensitive detection system (Timepix detector) to directly visualize the spatial distributions of the matrix-assisted laser desorption ionization ion cloud in a linear-time-of-flight (MALDI linear-ToF) as it is projected onto the detector surface. These time-resolved images allow direct visualization of m/z-dependent ion focusing effects that occur within the ion source of the instrument. The influence of key parameters, namely extraction voltage (E(V)), pulsed-ion extraction (PIE) delay, and even the matrix-dependent initial ion velocity was investigated and were found to alter the focusing properties of the ion-optical system. Under certain conditions where the spatial focal plane coincides with the detector plane, so-called x-y space focusing could be observed (i.e., the focusing of the ion cloud to a small, well-defined spot on the detector). Such conditions allow for the stigmatic ion imaging of intact proteins for the first time on a commercial linear ToF-MS system. In combination with the ion-optical magnification of the system (~100×), a spatial resolving power of 11–16 μm with a pixel size of 550 nm was recorded within a laser spot diameter of ~125 μm. This study demonstrates both the diagnostic and analytical advantages offered by the Timepix detector in ToF-MS.

The relationship between airborne small ions and particles in urban environments

NASA Astrophysics Data System (ADS)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2013-11-01

Ions play an important role in affecting climate and particle formation in the atmosphere. Small ions rapidly attach to particles in the air and, therefore, studies have shown that they are suppressed in polluted environments. Urban environments, in particular, are dominated by motor vehicle emissions and, since motor vehicles are a source of both particles and small ions, the relationship between these two parameters is not well known. In order to gain a better understanding of this relationship, an intensive campaign was undertaken where particles and small ions of both signs were monitored over two week periods at each of three sites A, B and C that were affected to varying degrees by vehicle emissions. Site A was close to a major road and reported the highest particle number and lowest small ion concentrations. Precursors from motor vehicle emissions gave rise to clear particle formation events on five days and, on each day this was accompanied by a suppression of small ions. Observations at Site B, which was located within the urban airshed, though not adjacent to motor traffic, showed particle enhancement but no formation events. Site C was a clean site, away from urban sources. This site reported the lowest particle number and highest small ion concentration. The positive small ion concentration was 10%-40% higher than the corresponding negative value at all sites. These results confirm previous findings that there is a clear inverse relationship between small ions and particles in urban environments dominated by motor vehicle emissions.

Design and simulation of ion optics for ion sources for production of singly charged ions

NASA Astrophysics Data System (ADS)

Zelenak, A.; Bogomolov, S. L.

2004-05-01

During the last 2 years different types of the singly charged ion sources were developed for FLNR (JINR) new projects such as Dubna radioactive ion beams, (Phase I and Phase II), the production of the tritium ion beam and the MASHA mass separator. The ion optics simulations for 2.45 GHz electron cyclotron resonance source, rf source, and the plasma ion source were performed. In this article the design and simulation results of the optics of new ion sources are presented. The results of simulation are compared with measurements obtained during the experiments.

A new mass spectrometer system for investigating laser-induced vaporization phenomena

NASA Technical Reports Server (NTRS)

Lincoln, K. A.

1974-01-01

A laser has been combined with a mass spectrometer in a new configuration developed for studies of high-temperature materials. A vacuum-lock, solid-sample inlet is mounted at one end of a cylindrical, high-vacuum chamber one meter in length with a nude ion-source, time-of-flight mass spectrometer at the opposite end. The samples are positioned along the axis of the chamber at distances up to one meter from the ion source, and their surfaces are vaporized by a pulsed laser beam entering via windows on one side of the chamber. The instrumentation along with its capabilities is described, and results from laser-induced vaporization of several graphites are presented.

Improved ion source

DOEpatents

Leung, K.N.; Ehlers, K.W.

1982-05-04

A magnetic filter for an ion source reduces the production of undesired ion species and improves the ion beam quality. High-energy ionizing electrons are confined by the magnetic filter to an ion source region, where the high-energy electrons ionize gas molecules. One embodiment of the magnetic filter uses permanent magnets oriented to establish a magnetic field transverse to the direction of travel of ions from the ion source region to the ion extraction region. In another embodiment, low energy 16 eV electrons are injected into the ion source to dissociate gas molecules and undesired ion species into desired ion species,

Ion source

DOEpatents

Leung, Ka-Ngo; Ehlers, Kenneth W.

1984-01-01

A magnetic filter for an ion source reduces the production of undesired ion species and improves the ion beam quality. High-energy ionizing electrons are confined by the magnetic filter to an ion source region, where the high-energy electrons ionize gas molecules. One embodiment of the magnetic filter uses permanent magnets oriented to establish a magnetic field transverse to the direction of travel of ions from the ion source region to the ion extraction region. In another embodiment, low energy 16 eV electrons are injected into the ion source to dissociate gas molecules and undesired ion species into desired ion species.

DUAL HEATED ION SOURCE STRUCTURE HAVING ARC SHIFTING MEANS

DOEpatents

Lawrence, E.O.

1959-04-14

An ion source is presented for calutrons, particularly an electrode arrangement for the ion generator of a calutron ion source. The ion source arc chamber is heated and an exit opening with thermally conductive plates defines the margins of the opening. These plates are electrically insulated from the body of the ion source and are connected to a suitable source of voltage to serve as electrodes for shaping the ion beam egressing from the arc chamber.

Corona discharge ionization of paracetamol molecule: peak assignment.

PubMed

Bahrami, H; Farrokhpour, H

2015-01-25

Ionization of paracetamol was investigated using ion mobility spectrometry equipped with a corona discharge ionization source. The measurements were performed in the positive ion mode and three peaks were observed in the ion mobility spectrum. Experimental evidence and theoretical calculations were used to correlate the peaks to related ionic species of paracetamol. Two peaks were attributed to protonated isomers of paracetamol and the other peak was attributed to paracetamol fragment ions formed by dissociation of the N-C bond after protonation of the nitrogen atom. It was observed that three sites of paracetamol compete for protonation and their relative intensities, depending on the sample concentration. The ratio of ion products could be predicted from the internal proton affinity of the protonation sites at each concentration. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of Double Bond Positions in Polyunsaturated Fatty Acids Using the Photochemical Paternò-Büchi Reaction with Acetone and Tandem Mass Spectrometry.

PubMed

Murphy, Robert C; Okuno, Toshiaki; Johnson, Christopher A; Barkley, Robert M

2017-08-15

The positions of double bonds along the carbon chain of methylene interrupted polyunsaturated fatty acids are unique identifiers of specific fatty acids derived from biochemical reactions that occur in cells. It is possible to obtain direct structural information as to these double bond positions using tandem mass spectrometry after collisional activation of the carboxylate anions of an acetone adduct at each of the double bond positions formed by the photochemical Paternò-Büchi reaction with acetone. This reaction can be carried out by exposing a small portion of an inline fused silica capillary to UV photons from a mercury vapor lamp as the sample is infused into the electrospray ion source of a mass spectrometer. Collisional activation of [M - H] - yields a series of reverse Paternò-Büchi reaction product ions that essentially are derived from cleavage of the original carbon-carbon double bonds that yield an isopropenyl carboxylate anion corresponding to each double bond location. Aldehydic reverse Paternò-Büchi product ions are much less abundant as the carbon chain length and number of double bonds increase. The use of a mixture of D 0 /D 6 -acetone facilitates identification of these double bonds indicating product ions as shown for arachidonic acid. If oxygen is present in the solvent stream undergoing UV photoactivation, ozone cleavage ions are also observed without prior collisional activation. This reaction was used to determine the double bond positions in a 20:3 fatty acid that accumulated in phospholipids of RAW 264.7 cells cultured for 3 days.

Fragmentation pathways of 2-substituted pyrrole derivatives using electrospray ionization ion trap and electrospray ionization quadrupole time-of-flight mass spectrometry.

PubMed

Liang, Xianrui; Guo, Zili; Yu, Chuanming

2013-10-30

Pyrrole derivatives are of considerable importance and are present in a wide range of natural products and used extensively in drug discovery. Fragmentation pathway studies play an important role in the structural identification of pyrrole derivatives. As a part of our ongoing work on heterocycles, fragmentation pathways of 2-substituted pyrrole derivatives were investigated by mass spectrometry (MS). Twelve pyrrole derivatives were synthesized and analyzed. Low-resolution fragmentation ions of all the compounds were generated by ion trap mass spectrometry (ITMS(n) ) with an electrospray ionization (ESI) source in positive mode. Hybrid quadrupole time-of-flight mass spectrometry (QTOFMS) was used to determine the elemental compositions of the resultant product ions. The side-chain substituents at the 2-position influence the fragmentation pathways. Typical losses of H2 O, aldehydes and pyrrole moieties from the [M + H](+) ion are observed for the compounds with side chains bearing aromatic groups at the 2-position of the pyrrole. However, losses of H2 O, alcohols and C3 H6 are the main cleavage pathways for compounds 6 and 12 with nonphenyl-substituted side chains at the 2-position. Typical fragmentation mechanisms of 2-substituted pyrrole derivatives are proposed and elucidated based on the observations of ITMS(n) and QTOFMS spectra. The results showed that the fragmentation pathways were remarkably influenced by the side-chain substituents at the 2-position of pyrrole. This investigation should have value in the structural identification of this series of molecules or compounds with similar structures. Copyright © 2013 John Wiley & Sons, Ltd.

Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source.

PubMed

Usmanov, D T; Chen, L C; Yu, Z; Yamabe, S; Sakaki, S; Hiraoka, K

2015-04-01

The high-sensitive detection of explosives is of great importance for social security and safety. In this work, the ion source for atmospheric pressure chemical ionization/mass spectrometry using alternating current corona discharge was newly designed for the analysis of explosives. An electromolded fine capillary with 115 µm inner diameter and 12 mm long was used for the inlet of the mass spectrometer. The flow rate of air through this capillary was 41 ml/min. Stable corona discharge could be maintained with the position of the discharge needle tip as close as 1 mm to the inlet capillary without causing the arc discharge. Explosives dissolved in 0.5 µl methanol were injected to the ion source. The limits of detection for five explosives with 50 pg or lower were achieved. In the ion/molecule reactions of trinitrotoluene (TNT), the discharge products of NOx (-) (x = 2,3), O3 and HNO3 originating from plasma-excited air were suggested to contribute to the formation of [TNT - H](-) (m/z 226), [TNT - NO](-) (m/z 197) and [TNT - NO + HNO3 ](-) (m/z 260), respectively. Formation processes of these ions were traced by density functional theory calculations. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

RFEA measurements of high-energy electrons in a helicon plasma device with expanding magnetic field

NASA Astrophysics Data System (ADS)

Gulbrandsen, Njål; Fredriksen, Åshild

2017-01-01

In the inductively coupled plasma of the Njord helicon device we have, for the same parameters as for which an ion beam exists, measured a downstream population of high-energy electrons emerging from the source. Separated measurements of energetic tail electrons was carried out by Retarding Field Energy Analyzer (RFEA) with a grounded entrance grid, operated in an electron collection mode. In a radial scan with the RFEA pointed toward the source, we found a significant population of high-energy electrons just inside the magnetic field line mapping to the edge of the source. A second peak in high-energy electrons density was observed in a radial position corresponding to the radius of the source. Also, throughout the main column a small contribution of high-energy electrons was observed. In a radial scan with a RFEA biased to collect ions a localized increase in the plasma ion density near the magnetic field line emerging from the plasma near the wall of the source was observed. This is interpreted as a signature of high-energy electrons ionizing the neutral gas. Also, a dip in the floating potential of a Langmuir probe is evident in this region where high-energy electrons is observed.

Metal catalyst technique for texturing silicon solar cells

DOEpatents

Ruby, Douglas S.; Zaidi, Saleem H.

2001-01-01

Textured silicon solar cells and techniques for their manufacture utilizing metal sources to catalyze formation of randomly distributed surface features such as nanoscale pyramidal and columnar structures. These structures include dimensions smaller than the wavelength of incident light, thereby resulting in a highly effective anti-reflective surface. According to the invention, metal sources present in a reactive ion etching chamber permit impurities (e.g. metal particles) to be introduced into a reactive ion etch plasma resulting in deposition of micro-masks on the surface of a substrate to be etched. Separate embodiments are disclosed including one in which the metal source includes one or more metal-coated substrates strategically positioned relative to the surface to be textured, and another in which the walls of the reaction chamber are pre-conditioned with a thin coating of metal catalyst material.

Investigations on caesium-free alternatives for H{sup −} formation at ion source relevant parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurutz, U.; Fantz, U.; AG Experimentelle Plasmaphysik, Institut für Physik, Universität Augsburg, 86135 Augsburg

2015-04-08

Negative hydrogen ions are efficiently produced in ion sources by the application of caesium. Due to a thereby induced lowering of the work function of a converter surface a direct conversion of impinging hydrogen atoms and positive ions into negative ions is maintained. However, due to the complex caesium chemistry and dynamics a long-term behaviour is inherent for the application of caesium that affects the stability and reliability of negative ion sources. To overcome these drawbacks caesium-free alternatives for efficient negative ion formation are investigated at the flexible laboratory setup HOMER (HOMogenous Electron cyclotron Resonance plasma). By the usage ofmore » a meshed grid the tandem principle is applied allowing for investigations on material induced negative ion formation under plasma parameters relevant for ion source operation. The effect of different sample materials on the ratio of the negative ion density to the electron density n{sub H{sup −}} /n{sub e} is compared to the effect of a stainless steel reference sample and investigated by means of laser photodetachment in a pressure range from 0.3 to 3 Pa. For the stainless steel sample no surface induced effect on the negative ion density is present and the measured negative ion densities are resulting from pure volume formation and destruction processes. In a first step the dependency of n{sub H{sup −}} /n{sub e} on the sample distance has been investigated for a caesiated stainless steel sample. At a distance of 0.5 cm at 0.3 Pa the density ratio is 3 times enhanced compared to the reference sample confirming the surface production of negative ions. In contrast for the caesium-free material samples, tantalum and tungsten, the same dependency on pressure and distance n{sub H{sup −}} /n{sub e} like for the stainless steel reference sample were obtained within the error margins: A density ratio of around 14.5% is measured at 4.5 cm sample distance and 0.3 Pa, linearly decreasing with decreasing distance to 7% at 1.5 cm. Thus, tantalum and tungsten do not significantly affect the negative ion density. First measurements conducted with LaB{sub 6} as well as with two types of diamond like carbon (DLC) n{sub H{sup −}} /n{sub e} of about 15% at 1 Pa were measured, which is comparable to the density ratio obtained for the stainless steel reference sample. At HOMER a surface induced enhancement of n{sub H{sup −}} is only observed when it exceeds the volume formation of H{sup −} which is also realistic for negative hydrogen ion sources.« less

Rapid screening of abused drugs by direct analysis in real time (DART) coupled to time-of-flight mass spectrometry (TOF-MS) combined with ion mobility spectrometry (IMS).

PubMed

Lian, Ru; Wu, Zhongping; Lv, Xiaobao; Rao, Yulan; Li, Haiyang; Li, Jinghua; Wang, Rong; Ni, Chunfang; Zhang, Yurong

2017-10-01

Increasing in cases involving drugs of abuse leads to heavy burden for law enforcement agencies, exacerbating demand for rapid screening technique. In this study, atmospheric pressure ionization technologies including direct analysis in real time (DART) ion source coupled to a time-of-flight mass spectrometer (DART-TOF-MS)as well asdopant-assisted positive photoionization ion mobility spectrometry (DAPP-IMS) without radioactivity were utilized together as the powerful analytical tool for the rapid screening and identification of 53 abused drugs.The limits of detection (LOD) were 0.05-2μg/mL when using DART-TOF-MS and 0.02-2μg when using DAPP-IMS which could satisfy the actual requirement in forensic science laboratory. The advantages of this method included fast response, high-throughput potential, high specificity, and minimal sample preparation. A screening library of reduced mobility (K 0 ), accurate mass of informative precursor ion ([M+H] + ) and fragment ions was established respectively by employing a bench-top DAPP-IMS and TOF-MS in-source collision induced dissociation (CID) mode. Then the standardized screening procedure was developed with criteria for the confirmation of positive result. A total of 50 seized drug samples provided by local forensic laboratory we reanalyzed to testify the utility of the method. This study suggests that a method combing DART-TOF-MS and DAPP-IMS is promising for the rapid screening and identification of abused drugs with minimal sample preparation and absence of chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

Low latitude middle atmosphere ionization studies

NASA Technical Reports Server (NTRS)

Bassi, J. P.

1976-01-01

Low latitude middle atmosphere ionization was studied with data obtained from three blunt conductivity probes and one Gerdien condenser. An investigation was conducted into the effects of various ionization sources in the 40 to 65 Km altitude range. An observed enhancement of positive ion conductivity taking place during the night can be explained by an atmsopheric effect, with cosmic rays being the only source of ionization only if the ion-ion recombination coefficient (alpha sub i) is small(10 to the -7 power cu cm/s) and varies greatly with altitude. More generally accepted values of alpha sub i ( approximately equal to 3x10 to the -7 power cu cm/s) require an additional source of ionization peaking at about 65 Km, and corresponding approximately to the integrated effect of an X-ray flux measured on a rocket flown in conjunction with the ionization measurements. The reasonable assumption of an alpha sub i which does not vary with altitude in the 50-70 Km range implies an even greater value alpha sub i and a more intense and harder X-ray spectrum.

High-Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

DOEpatents

Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

2004-11-16

A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source.

PubMed

Pikin, A; Beebe, E N; Raparia, D

2013-03-01

Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 ÷ 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 ÷ 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pikin, A.; Beebe, E. N.; Raparia, D.

Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current upmore » to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 Division-Sign 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 Division-Sign 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.« less

Source Apportionment of PM2.5 Mass and Optical Attenuation Over an Ecologically Sensitive Zone in Central India by Positive Matrix Factorization

NASA Astrophysics Data System (ADS)

Nirmalkar, J.; Raman, R. S.

2016-12-01

Ambient PM2.5 samples (N=366) were collected over an ecologically sensitive zone (Van Vihar National Park) in Bhopal, Central India for two years (01 January, 2012 to 31 December, 2013). Samples were collected using three co-located Mini-Vol® samplers on Teflon, Nylon, and Quartz filter substrates. The aerosol was then chemically characterized for water-soluble inorganic ions, elements, and carbon fractions (elemental carbon and organic carbon) using ion chromatography, ED-XRF, and thermal-optical EC/OC analyzer, respectively. The optical attenuation (at 370 nm and 800 nm) of PM2.5 aerosols was also determined by optical transmissometry (OT-21). The application of Positive matrix factorization (PMF) to a combination of PM2.5 mass, its ions, elements, carbon fractions, and optical attenuation and its outcomes will be discussed.

Rocket-borne time-of-flight mass spectrometry

NASA Technical Reports Server (NTRS)

Reiter, R. F.

1976-01-01

Theoretical and numerical analyses are made of planar, cylindrical and spherical-electrode two-field time-of-flight mass spectrometers in order to optimize their operating conditions. A method is introduced which can improve the resolving power of these instruments by a factor of 7.5. Potential barrier gating in time-of-flight mass spectrometers is also analyzed. Experimental studies of a miniature cylindrical-electrode and a hemispherical-electrode time-of-flight mass spectrometer are presented. Their sensitivity and ability to operate at D-region pressures with an open source make them ideal instruments for D-region ion composition measurements. A sounding rocket experiment package carrying a cylindrical electrode time-of-flight mass spectrometer was launched. The data indicate that essentially 100% of the positive electric charge on positive ions is carried by ions with mass-to-charge ratios greater than 500 below an altitude of 92 km. These heavy charge carriers were present at altitudes up to about 100 km.

First β-ν correlation measurement from the recoil-energy spectrum of Penning trapped Ar35 ions

NASA Astrophysics Data System (ADS)

Van Gorp, S.; Breitenfeldt, M.; Tandecki, M.; Beck, M.; Finlay, P.; Friedag, P.; Glück, F.; Herlert, A.; Kozlov, V.; Porobic, T.; Soti, G.; Traykov, E.; Wauters, F.; Weinheimer, Ch.; Zákoucký, D.; Severijns, N.

2014-08-01

We demonstrate a novel method to search for physics beyond the standard model by determining the β-ν angular correlation from the recoil-ion energy distribution after β decay of ions stored in a Penning trap. This recoil-ion energy distribution is measured with a retardation spectrometer. The unique combination of the spectrometer with a Penning trap provides a number of advantages, e.g., a high recoil-ion count rate and low sensitivity to the initial position and velocity distribution of the ions and completely different sources of systematic errors compared to other state-of-the-art experiments. Results of a first measurement with the isotope Ar35 are presented. Although currently at limited precision, we show that a statistical precision of about 0.5% is achievable with this unique method, thereby opening up the possibility of contributing to state-of-the-art searches for exotic currents in weak interactions.

Operation of a high impedance applied-B extraction ion diode on the SABRE positive polarity linear induction accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, D.L.; Cuneo, M.E.; McKay, P.F.

We present results from initial experiments with a high impedance applied-B extraction diode on the SABRE ten stage linear induction accelerator (6.7 MV, 300 kA). We have demonstrated efficient coupling of power from the accelerator through an extended MITL (Magnetically Insulated Transmission Line) into a high intensity ion beam. Both MITL electron flow in the diode region and ion diode behavior, including ion source turn-on, virtual cathode formation and evolution, enhancement delay, and ion coupling efficiency, are strongly influenced by the geometry of the diode insulating magnetic field. For our present diode electrode geometry, electrons from the diode feed stronglymore » influence the evolution of the virtual cathode. Both experimental data and particle-in-cell numerical simulations show that uniform insulation of these feed electrons is required for uniform ion emission and efficient diode operation.« less

A Multicusp Ion Source for Radioactive Ion Beams

NASA Astrophysics Data System (ADS)

Wutte, D.; Freedman, S.; Gough, R.; Lee, Y.; Leitner, M.; Leung, K. N.; Lyneis, C.; Picard, D. S.; Sun, L.; Williams, M. D.; Xie, Z. Q.

1997-05-01

In order to produce a radioactive ion beam of (14)O+, a 10-cm-diameter, 13.56 MHz radio frequency (rf) driven multicusp ion source is now being developed at Lawrence Berkeley National Laboratory. In this paper we describe the specific ion source design and the basic ion source characteristics using Ar, Xe and a 90types of measurements have been performed: extractable ion current, ion species distributions, gas efficiency, axial energy spread and ion beam emittance measurements. The source can generate ion current densities of approximately 60 mA/cm2 . In addition the design of the ion beam extraction/transport system for the actual experimental setup for the radioactive beam line will be presented.

Transition from moving to stationary double layers in a single-ended Q machine

NASA Technical Reports Server (NTRS)

Song, Bin; Merlino, R. L.; D'Angelo, N.

1990-01-01

Large-amplitude (less than about 100 percent) relaxation oscillations in the plasma potential are known to be generated when the cold endplate of a single-ended Q machine is biased positively. These oscillations are associated with double layers that form near the hot plate (plasma source) and travel toward the endplate at about the ion-acoustic velocity. At the endplate they dissolve and then form again near the hot plate, the entire process repeating itself in a regular manner. By admitting a sufficient amount of neutral gas into the system, the moving double layers were slowed down and eventually stopped. The production of stationary double layers requires an ion source on the high-potential side of the double layers. These ions are provided by ionization of the neutral gas by electrons that are accelerated through the double layer. The dependence of the critical neutral gas pressure required for stationary double-layer formation on endplate voltage, magnetic field strength, and neutral atom mass has been examined. These results are discussed in terms of a simple model of ion production and loss, including ion losses across the magnetic field.

Ion-induced nuclear radiotherapy

DOEpatents

Horn, K.M.; Doyle, B.L.

1996-08-20

Ion-induced Nuclear Radiotherapy (INRT) is a technique for conducting radiosurgery and radiotherapy with a very high degree of control over the spatial extent of the irradiated volume and the delivered dose. Based upon the concept that low energy, ion induced atomic and nuclear reactions can be used to produce highly energetic reaction products at the site of a tumor, the INRT technique is implemented through the use of a conduit-needle or tube which conducts a low energy ion beam to a position above or within the intended treatment area. At the end of the conduit-needle or tube is a specially fabricated target which, only when struck by the ion beam, acts as a source of energetic radiation products. The inherent limitations in the energy, and therefore range, of the resulting reaction products limits the spatial extent of irradiation to a pre-defined volume about the point of reaction. Furthermore, since no damage is done to tissue outside this irradiated volume, the delivered dose may be made arbitrarily large. INRT may be used both as a point-source of radiation at the site of a small tumor, or as a topical bath of radiation to broad areas of diseased tissue. 25 figs.

Ion-induced nuclear radiotherapy

DOEpatents

Horn, Kevin M.; Doyle, Barney L.

1996-01-01

Ion-induced Nuclear Radiotherapy (INRT) is a technique for conducting radiosurgery and radiotherapy with a very high degree of control over the spatial extent of the irradiated volume and the delivered dose. Based upon the concept that low energy, ion induced atomic and nuclear reactions can be used to produce highly energetic reaction products at the site of a tumor, the INRT technique is implemented through the use of a conduit-needle or tube which conducts a low energy ion beam to a position above or within the intended treatment area. At the end of the conduit-needle or tube is a specially fabricated target which, only when struck by the ion beam, acts as a source of energetic radiation products. The inherent limitations in the energy, and therefore range, of the resulting reaction products limits the spatial extent of irradiation to a pre-defined volume about the point of reaction. Furthermore, since no damage is done to tissue outside this irradiated volume, the delivered dose may be made arbitrarily large. INRT may be used both as a point-source of radiation at the site of a small tumor, or as a topical bath of radiation to broad areas of diseased tissue.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murzin, I.H.; Tompa, G.S.; Wei, J.

The authors report the results of using sputtering and negative carbon ion sources to prepare thin films of carbon nitride. In this work, they compare the structural, tribological, and optical properties of the carbon nitride films that were prepared by two different ion assisted techniques. In the first approach they used a magnetron gun to sputter deposit carbon in a nitrogen atmosphere. The second method utilized a beam of negatively charged carbon ions of 1 to 5 {micro}A/cm{sup 2} current density impinging the substrate simultaneously with a positive nitrogen ion beam produced by a Kaufman source. They were able tomore » synthesize microscopically smooth coatings with the carbon to nitrogen ratio of 1:0.47. These films possess wear rates lower than 5 {times} 10{sup {minus}7} mm{sup 3}/Nm and friction coefficients in the range of 0.16 to 0.6. Raman spectroscopy revealed that the magnetron sputtered films are more structurally disordered than those formed with the negative carbon ion gun. FTIR showed the presence of the C{triple_bond}N stretching mode in both types of films. Finally, spectroscopic ellipsometry produced films with dielectric constants as low as 2.3 in the photon energy range from 1.2 to 5 eV.« less

Numerical Model of the Plasma Sheath Generated by the Plasma Source Instrument Aboard the Polar Satellite

NASA Technical Reports Server (NTRS)

Singh, N.; Leung, W. C.; Moore, T. E.; Craven, P. D.

2001-01-01

The plasma sheath generated by the operation of the Plasma Source Instrument (PSI) aboard the Polar satellite is studied by using a three-dimensional particle-in-cell (PIC) code. When the satellite passes through the region of low-density plasma, the satellite charges to positive potentials as high as 40-50 V, owing to the photoelectron emission. In such a case, ambient core ions cannot accurately be measured or detected. The goal of the onboard PSI is to reduce the floating potential of the satellite to a sufficiently low value so that the ions in the polar wind become detectable. When the PSI is operated, ion-rich xenon plasma is ejected from the satellite, such that the floating potential of the satellite is reduced and is maintained at approximately 2 V. Accordingly, in our three-dimensional PIC simulation we considered that the potential of the satellite is 2 V as a fixed bias. Considering the relatively high density of the xenon plasma in the sheath (10-10(exp 3)/cc), the ambient plasma of low density (<1/cc) is neglected. In the simulations the electric fields and plasma dynamics are calculated self-consistently. We found that an 'apple'-shape positive potential sheath forms surrounding the satellite. In the region near the PSI emission a high positive potential hill develops. Near the Thermal Ion Dynamics Experiment detector away from the PSI, the potentials are sufficiently low for the ambient polar wind ions to reach it. In the simulations it takes only about a couple of tens of electron gyroperiods for the sheath to reach a quasi steady state. This time is approximately the time taken by the heavy Xe(+) ions to expand up to about one average Larmor radius of electrons from the satellite surface. After this time the expansion of the sheath in directions transverse to the ambient magnetic field slows down because the electrons are magnetized. Using the quasi steady sheath, we performed trajectory calculations to characterize the detector response to a highly supersonic polar wind flow. The detected ions' velocity distribution shows significant deviations from a shifted Maxwellian in the ambient polar wind population. The deviations are caused by the effects of electric fields on the ions' motion as they traverse the sheath.

On- and off-line monitoring of ion beam treatment

NASA Astrophysics Data System (ADS)

Parodi, Katia

2016-02-01

Ion beam therapy is an emerging modality for high precision radiation treatment of cancer. In comparison to conventional radiation sources (photons, electrons), ion beams feature major dosimetric advantages due to their finite range with a localized dose deposition maximum, the Bragg peak, which can be selectively adjusted in depth. However, due to several sources of treatment uncertainties, full exploitation of these dosimetric advantages in clinical practice would require the possibility to visualize the stopping position of the ions in vivo, ideally in real-time. To this aim, different imaging methods have been proposed and investigated, either pre-clinically or even clinically, based on the detection of prompt or delayed radiation following nuclear interaction of the beam with the irradiated tissue. However, the chosen or ad-hoc developed instrumentation has often relied on technologies originally conceived for different applications, thus compromising on the achievable performances for the sake of cost-effectiveness. This contribution will review major examples of used instrumentation and related performances, identifying the most promising detector developments for next generation devices especially dedicated to on-line monitoring of ion beam treatment. Moreover, it will propose an original combination of different techniques in a hybrid detection scheme, aiming to make the most of complementary imaging methods and open new perspectives of image guidance for improved precision of ion beam therapy.

The Cadarache negative ion experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massmann, P.; Bottereau, J.M.; Belchenko, Y.

1995-12-31

Up to energies of 140 keV neutral beam injection (NBI) based on positive ions has proven to be a reliable and flexible plasma heating method and has provided major contributions to most of the important experiments on virtually all large tokamaks around the world. As a candidate for additional heating and current drive on next step fusion machines (ITER ao) it is hoped that NBI can be equally successful. The ITER NBI parameters of 1 MeV, 50 MW D{degree} demand primary D{sup {minus}} beams with current densities of at least 15 mA/cm{sup 2}. Although considerable progress has been made inmore » the area of negative ion production and acceleration the high demands still require substantial and urgent development. Regarding negative ion production Cs seeded plasma sources lead the way. Adding a small amount of Cs to the discharge (Cs seeding) not only increases the negative ion yield by a factor 3--5 but also has the advantage that the discharge can be run at lower pressures. This is beneficial for the reduction of stripping losses in the accelerator. Multi-ampere negative ion production in a large plasma source is studied in the MANTIS experiment. Acceleration and neutralization at ITER relevant parameters is the objective of the 1 MV SINGAP experiment.« less

Focused electron and ion beam systems

DOEpatents

Leung, Ka-Ngo; Reijonen, Jani; Persaud, Arun; Ji, Qing; Jiang, Ximan

2004-07-27

An electron beam system is based on a plasma generator in a plasma ion source with an accelerator column. The electrons are extracted from a plasma cathode in a plasma ion source, e.g. a multicusp plasma ion source. The beam can be scanned in both the x and y directions, and the system can be operated with multiple beamlets. A compact focused ion or electron beam system has a plasma ion source and an all-electrostatic beam acceleration and focusing column. The ion source is a small chamber with the plasma produced by radio-frequency (RF) induction discharge. The RF antenna is wound outside the chamber and connected to an RF supply. Ions or electrons can be extracted from the source. A multi-beam system has several sources of different species and an electron beam source.

Integration of paper spray ionization high-field asymmetric waveform ion mobility spectrometry for forensic applications.

PubMed

Tsai, Chia-Wei; Tipple, Christopher A; Yost, Richard A

2018-04-15

Paper spray ionization (PSI) is an attractive ambient ionization source for mass spectrometry (MS) since it allows the combination of surface sampling and ionization. The minimal sample preparation inherent in this approach greatly reduces the time needed for analysis. However, the ions generated from interfering compounds in the sample and the paper substrate may interfere with the analyte ions. Therefore, the integration of PSI with high-field asymmetric ion mobility spectrometry (FAIMS) is of significant interest since it should reduce the background ions entering the mass analyzer without complicating the analysis or increasing analysis time. Here we demonstrate the integration of PSI with FAIMS/MS and its potential for analysis of samples of forensic interest. In this work, the parameters that can influence the integration, including sampling and ionization by paper spray, the FAIMS separation of analytes from each other and background interferences, and the length of time that a usable signal can be observed for explosives on paper, were evaluated with the integrated system. In the negative ion analysis of 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), amounts as low as 1 ng on paper were readily observed. The successful positive ion separation of a set of illicit drugs including heroin, methamphetamine, and cocaine was also achieved. In addition, the positive ion analysis of the chemical warfare agent simulants dimethyl methylphosphonate (DMMP) and diisopropyl methylphosphonate (DIMP) was evaluated. The integration of PSI-FAIMS/MS was demonstrated for the analyses of explosives in negative ion mode and for illicit drugs and CW simulants in positive mode. Paper background ions that could interfere with these analyses were separated by FAIMS. The compensation voltage of an ion obtained by FAIMS provided an additional identification parameter to be combined with the mass spectrum for each analyte. Copyright © 2018 John Wiley & Sons, Ltd.

Microfabricated ion frequency standard

DOEpatents

Schwindt, Peter; Biedermann, Grant; Blain, Matthew G.; Stick, Daniel L.; Serkland, Darwin K.; Olsson, III, Roy H.

2010-12-28

A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

An ion source module for the Beijing Radioactive Ion-beam Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, B., E-mail: cui@ciae.ac.cn; Huang, Q.; Tang, B.

2014-02-15

An ion source module is developed for Beijing Radioactive Ion-beam Facility. The ion source module is designed to meet the requirements of remote handling. The connection and disconnection of the electricity, cooling and vacuum between the module and peripheral units can be executed without on-site manual work. The primary test of the target ion source has been carried out and a Li{sup +} beam has been extracted. Details of the ion source module and its primary test results are described.

Critical assessment of ionization patterns and applications of ambient desorption/ionization mass spectrometry using FAPA-MS.

PubMed

Brüggemann, Martin; Karu, Einar; Hoffmann, Thorsten

2016-02-01

Ambient desorption/ionization mass spectrometry (MS) has gained growing interest during the last decade due to its high analytical performance and yet simplicity. Here, one of the recently developed ambient desorption/ionization MS sources, the flowing atmospheric-pressure afterglow (FAPA) source, was investigated in detail regarding background ions and typical ionization patterns in the positive as well as the negative ion mode for a variety of compound classes, comprising alkanes, alcohols, aldehydes, ketones, carboxylic acids, organic peroxides and alkaloids. A broad range of signals for adducts and losses was found, besides the usually emphasized detection of quasimolecular ions, i.e. [M + H](+) and [M - H](-) in the positive and the negative mode, respectively. It was found that FAPA-MS is best suited for polar analytes containing nitrogen and/or oxygen functionalities, e.g. carboxylic acids, with low molecular weights and relatively high vapor pressures. In addition, the source was used in proof-of-principle studies, illustrating the capabilities and limitations of the technique: Firstly, traces of cocaine were detected and unambiguously identified on euro banknotes using FAPA ionization in combination with tandem MS, suggesting a correlation between cocaine abundance and age of the banknote. Secondly, FAPA-MS was used for the identification of acidic marker compounds in organic aerosol samples, indicating yet-undiscovered matrix and sample surface effects of ionization pathways in the afterglow region. Copyright © 2016 John Wiley & Sons, Ltd.

Ion source research and development at University of Jyväskylä: Studies of different plasma processes and towards the higher beam intensities.

PubMed

Koivisto, H; Kalvas, T; Tarvainen, O; Komppula, J; Laulainen, J; Kronholm, R; Ranttila, K; Tuunanen, J; Thuillier, T; Xie, D; Machicoane, G

2016-02-01

Several ion source related research and development projects are in progress at the Department of Physics, University of Jyväskylä (JYFL). The work can be divided into investigation of the ion source plasma and development of ion sources, ion beams, and diagnostics. The investigation covers the Electron Cyclotron Resonance Ion Source (ECRIS) plasma instabilities, vacuum ultraviolet (VUV) and visible light emission, photon induced electron emission, and the development of plasma diagnostics. The ion source development covers the work performed for radiofrequency-driven negative ion source, RADIS, beam line upgrade of the JYFL 14 GHz ECRIS, and the development of a new room-temperature-magnet 18 GHz ECRIS, HIISI.

Using neutral beams as a light ion beam probe (invited)

DOE PAGES

Chen, Xi; Heidbrink, William W.; Van Zeeland, Michael A.; ...

2014-08-05

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of 1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge, and 2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fieldsmore » appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g. Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally-imposed 3D fields, e.g. magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. Additionally, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.« less

Using neutral beams as a light ion beam probe (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xi, E-mail: chenxi@fusion.gat.com; Heidbrink, W. W.; Van Zeeland, M. A.

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fieldsmore » appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.« less

Using neutral beams as a light ion beam probe (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xi; Heidbrink, William W.; Van Zeeland, Michael A.

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of 1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge, and 2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fieldsmore » appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g. Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally-imposed 3D fields, e.g. magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. Additionally, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.« less

Boundary conditions on the plasma emitter surface in the presence of a particle counter flow: I. Ion emitter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Astrelin, V. T., E-mail: V.T.Astrelin@inp.nsk.su; Kotelnikov, I. A.

Emission of positively charged ions from a plasma emitter irradiated by a counterpropagating electron beam is studied theoretically. A bipolar diode with a plasma emitter in which the ion temperature is lower than the electron temperature and the counter electron flow is extracted from the ion collector is calculated in the one-dimensional model. An analog of Bohm’s criterion for ion emission in the presence of a counterpropagating electron beam is derived. The limiting density of the counterpropagating beam in a bipolar diode operating in the space-charge-limited-emission regime is calculated. The full set of boundary conditions on the plasma emitter surfacemore » that are required for operation of the high-current optics module in numerical codes used to simulate charged particle sources is formulated.« less

Improved Multiple-Species Cyclotron Ion Source

NASA Technical Reports Server (NTRS)

Soli, George A.; Nichols, Donald K.

1990-01-01

Use of pure isotope 86Kr instead of natural krypton in multiple-species ion source enables source to produce krypton ions separated from argon ions by tuning cylcotron with which source used. Addition of capability to produce and separate krypton ions at kinetic energies of 150 to 400 MeV necessary for simulation of worst-case ions occurring in outer space.

Bidirectional tornado modes on the Joint European Torus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandquist, P.; Sharapov, S. E.; Lisak, M.

In discharges on the Joint European Torus [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)] with safety factor q(0)<1 and high-power ion cyclotron resonance heating (ICRH), monster sawtooth crashes are preceded by frequency sweeping 'tornado modes' in the toroidal Alfven eigenmode frequency range. A suite of equilibrium and spectral magnetohydrodynamical codes is used for explaining the observed evolution of the tornado mode frequency and for identifying temporal evolution of the safety factor inside the q=1 radius just before sawtooth crashes. In some cases, the tornado modes are observed simultaneously with both positive and negative toroidal modemore » numbers. Hence, a free energy source other than the radial gradient of the energetic ion pressure exciting these modes is sought. The distribution function of the ICRH-accelerated ions is assessed with the SELFO code [J. Hedin et al., Nucl. Fusion 42, 527 (2002)] and energetic particle drive due to the velocity space anisotropy of ICRH-accelerated ions is considered analytically as the possible source for excitation of bidirectional tornado modes.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elizondo-Decanini, Juan M.

Short pulse neutron generators are described herein. In a general embodiment, the short pulse neutron generator includes a Blumlein structure. The Blumlein structure includes a first conductive plate, a second conductive plate, a third conductive plate, at least one of an inductor or a resistor, a switch, and a dielectric material. The first conductive plate is positioned relative to the second conductive plate such that a gap separates these plates. A vacuum chamber is positioned in the gap, and an ion source is positioned to emit ions in the vacuum chamber. The third conductive plate is electrically grounded, and themore » switch is operable to electrically connect and disconnect the second conductive plate and the third conductive plate. The at least one of the resistor or the inductor is coupled to the first conductive plate and the second conductive plate.« less

The identification of disulfides in ricin D using proteolytic cleavage followed by negative-ion nano-electrospray ionization mass spectrometry of the peptide fragments.

PubMed

Tran, T T Nha; Brinkworth, Craig S; Bowie, John H

2015-01-30

To use negative-ion nano-electrospray ionization mass spectrometry of peptides from the tryptic digest of ricin D, to provide sequence information; in particular, to identify disulfide position and connectivity. Negative-ion fragmentations of peptides from the tryptic digest of ricin D was studied using a Waters QTOF2 mass spectrometer operating in MS and MS(2) modes. Twenty-three peptides were obtained following high-performance liquid chromatography and studied by negative-ion mass spectrometry covering 73% of the amino-acid residues of ricin D. Five disulfide-containing peptides were identified, three intermolecular and two intramolecular disulfide-containing peptides. The [M-H](-) anions of the intermolecular disulfides undergo facile cleavage of the disulfide units to produce fragment peptides. In negative-ion collision-induced dissociation (CID) these source-formed anions undergo backbone cleavages, which provide sequencing information. The two intramolecular disulfides were converted proteolytically into intermolecular disulfides, which were identified as outlined above. The positions of the five disulfide groups in ricin D may be determined by characteristic negative-ion cleavage of the disulfide groups, while sequence information may be determined using the standard negative-ion backbone cleavages of the resulting cleaved peptides. Negative-ion mass spectrometry can also be used to provide partial sequencing information for other peptides (i.e. those not containing Cys) using the standard negative-ion backbone cleavages of these peptides. Copyright © 2014 John Wiley & Sons, Ltd.

Development and tests of molybdenum armored copper components for MITICA ion source

NASA Astrophysics Data System (ADS)

Pavei, Mauro; Böswirth, Bernd; Greuner, Henri; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo

2016-02-01

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

Development and tests of molybdenum armored copper components for MITICA ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pavei, Mauro, E-mail: mauro.pavei@igi.cnr.it; Marcuzzi, Diego; Rizzolo, Andrea

2016-02-15

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analysesmore » of the prototypes simulating the test conditions in GLADIS as well as the experimental results.« less

Development and tests of molybdenum armored copper components for MITICA ion source.

PubMed

Pavei, Mauro; Böswirth, Bernd; Greuner, Henri; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo

2016-02-01

In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

Liquid metal ion source and alloy

DOEpatents

Clark, Jr., William M.; Utlaut, Mark W.; Behrens, Robert G.; Szklarz, Eugene G.; Storms, Edmund K.; Santandrea, Robert P.; Swanson, Lynwood W.

1988-10-04

A liquid metal ion source and alloy, wherein the species to be emitted from the ion source is contained in a congruently vaporizing alloy. In one embodiment, the liquid metal ion source acts as a source of arsenic, and in a source alloy the arsenic is combined with palladium, preferably in a liquid alloy having a range of compositions from about 24 to about 33 atomic percent arsenic. Such an alloy may be readily prepared by a combustion synthesis technique. Liquid metal ion sources thus prepared produce arsenic ions for implantation, have long lifetimes, and are highly stable in operation.

Ion Beam Propulsion Study

NASA Technical Reports Server (NTRS)

2008-01-01

The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

Development of the ion source for cluster implantation

NASA Astrophysics Data System (ADS)

Kulevoy, T. V.; Seleznev, D. N.; Kozlov, A. V.; Kuibeda, R. P.; Kropachev, G. N.; Alexeyenko, O. V.; Dugin, S. N.; Oks, E. M.; Gushenets, V. I.; Hershcovitch, A.; Jonson, B.; Poole, H. J.

2014-02-01

Bernas ion source development to meet needs of 100s of electron-volt ion implanters for shallow junction production is in progress in Institute for Theoretical and Experimental Physics. The ion sources provides high intensity ion beam of boron clusters under self-cleaning operation mode. The last progress with ion source operation is presented. The mechanism of self-cleaning procedure is described.

Air ion concentrations in various urban outdoor environments

NASA Astrophysics Data System (ADS)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2010-06-01

Atmospheric ions are produced by many natural and anthropogenic sources and their concentrations vary widely between different environments. There is very little information on their concentrations in different types of urban environments, how they compare across these environments and their dominant sources. In this study, we measured airborne concentrations of small ions, particles and net particle charge at 32 different outdoor sites in and around a major city in Australia and identified the main ion sources. Sites were classified into seven groups as follows: park, woodland, city centre, residential, freeway, power lines and power substation. Generally, parks were situated away from ion sources and represented the urban background value of about 270 ions cm -3. Median concentrations at all other groups were significantly higher than in the parks. We show that motor vehicles and power transmission systems are two major ion sources in urban areas. Power lines and substations constituted strong unipolar sources, while motor vehicle exhaust constituted strong bipolar sources. The small ion concentration in urban residential areas was about 960 cm -3. At sites where ion sources were co-located with particle sources, ion concentrations were inhibited due to the ion-particle attachment process. These results improved our understanding on air ion distribution and its interaction with particles in the urban outdoor environment.

Negative ion source with low temperature transverse divergence optical system

DOEpatents

Whealton, John H.; Stirling, William L.

1986-01-01

A negative ion source is provided which has extremely low transverse divergence as a result of a unique ion focusing system in which the focal line of an ion beam emanating from an elongated, concave converter surface is outside of the ion exit slit of the source and the path of the exiting ions. The beam source operates with a minimum ion temperature which makes possible a sharply focused (extremely low transverse divergence) ribbon like negative ion beam.

Negative ion source with low temperature transverse divergence optical system

DOEpatents

Whealton, J.H.; Stirling, W.L.

1985-03-04

A negative ion source is provided which has extremely low transverse divergence as a result of a unique ion focusing system in which the focal line of an ion beam emanating from an elongated, concave converter surface is outside of the ion exit slit of the source and the path of the exiting ions. The beam source operates with a minimum ion temperature which makes possible a sharply focused (extremely low transverse divergence) ribbon like negative ion beam.

Ion Storage with the High Performance Antiproton Trap (HiPAT)

NASA Technical Reports Server (NTRS)

Martin, James; Lewis, Raymond; Chakrabarti, Suman; Pearson, Boise

2002-01-01

The matter antimatter reaction represents the densest form of energy storage/release known to modern physics: as such it offers one of the most compact sources of power for future deep space exploration. To take the first steps along this path, NASA-Marshall Space Flight Center is developing a storage system referred to as the High Performance Antiproton Trap (HiPAT) with a goal of maintaining 10(exp 12) particles for up to 18 days. Experiments have been performed with this hardware using normal matter (positive hydrogen ions) to assess the device's ability to hold charged particles. These ions are currently created using an electron gun method to ionize background gas; however, this technique is limited by the quantity that can be captured. To circumvent this issue, an ion source is currently being commissioned which will greatly increase the number of ions captured and more closely simulate actual operations expected at an antiproton production facility. Ions have been produced, stored for various time intervals, and then extracted against detectors to measure species, quantity and energy. Radio frequency stabilization has been tested as a method to prolong ion lifetime: results show an increase in the baseline 1/e lifetime of trapped particles from hours to days. Impurities in the residual background gas (typically carbon-containing species CH4, CO, CO2, etc.) present a continuing problem by reducing the trapped hydrogen population through the mechanism of ion charge exchange.

Determination of gas phase protein ion densities via ion mobility analysis with charge reduction.

PubMed

Maisser, Anne; Premnath, Vinay; Ghosh, Abhimanyu; Nguyen, Tuan Anh; Attoui, Michel; Hogan, Christopher J

2011-12-28

We use a charge reduction electrospray (ESI) source and subsequent ion mobility analysis with a differential mobility analyzer (DMA, with detection via both a Faraday cage electrometer and a condensation particle counter) to infer the densities of single and multiprotein ions of cytochrome C, lysozyme, myoglobin, ovalbumin, and bovine serum albumin produced from non-denaturing (20 mM aqueous ammonium acetate) and denaturing (1 : 49.5 : 49.5, formic acid : methanol : water) ESI. Charge reduction is achieved through use of a Po-210 radioactive source, which generates roughly equal concentrations of positive and negative ions. Ions produced by the source collide with and reduce the charge on ESI generated drops, preventing Coulombic fissions, and unlike typical protein ESI, leading to gas-phase protein ions with +1 to +3 excess charges. Therefore, charge reduction serves to effectively mitigate any role that Coulombic stretching may play on the structure of the gas phase ions. Density inference is made via determination of the mobility diameter, and correspondingly the spherical equivalent protein volume. Through this approach it is found that for both non-denaturing and denaturing ESI-generated ions, gas-phase protein ions are relatively compact, with average densities of 0.97 g cm(-3) and 0.86 g cm(-3), respectively. Ions from non-denaturing ESI are found to be slightly more compact than predicted from the protein crystal structures, suggesting that low charge state protein ions in the gas phase are slightly denser than their solution conformations. While a slight difference is detected between the ions produced with non-denaturing and denaturing ESI, the denatured ions are found to be much more dense than those examined previously by drift tube mobility analysis, in which charge reduction was not employed. This indicates that Coulombic stretching is typically what leads to non-compact ions in the gas-phase, and suggests that for gas phase measurements to be correlated to biomolecular structures in solution, low charge state ions should be analyzed. Further, to determine if different solution conditions give rise to ions of different structure, ions of similar charge state should be compared. Non-denatured protein ion densities are found to be in excellent agreement with non-denatured protein ion densities inferred from prior DMA and drift tube measurements made without charge reduction (all ions with densities in the 0.85-1.10 g cm(-3) range), showing that these ions are not strongly influenced by Coulombic stretching nor by analysis method.

Design study of primary ion provider for relativistic heavy ion collider electron beam ion source.

PubMed

Kondo, K; Kanesue, T; Tamura, J; Okamura, M

2010-02-01

Brookhaven National Laboratory has developed the new preinjector system, electron beam ion source (EBIS) for relativistic heavy ion collider (RHIC) and National Aeronautics and Space Administration Space Radiation Laboratory. Design of primary ion provider is an essential problem since it is required to supply beams with different ion species to multiple users simultaneously. The laser ion source with a defocused laser can provide a low charge state and low emittance ion beam, and is a candidate for the primary ion source for RHIC-EBIS. We show a suitable design with appropriate drift length and solenoid, which helps to keep sufficient total charge number with longer pulse length. The whole design of primary ion source, as well as optics arrangement, solid targets configuration and heating about target, is presented.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koivisto, H., E-mail: hannu.koivisto@phys.jyu.fi; Kalvas, T.; Tarvainen, O.

Several ion source related research and development projects are in progress at the Department of Physics, University of Jyväskylä (JYFL). The work can be divided into investigation of the ion source plasma and development of ion sources, ion beams, and diagnostics. The investigation covers the Electron Cyclotron Resonance Ion Source (ECRIS) plasma instabilities, vacuum ultraviolet (VUV) and visible light emission, photon induced electron emission, and the development of plasma diagnostics. The ion source development covers the work performed for radiofrequency-driven negative ion source, RADIS, beam line upgrade of the JYFL 14 GHz ECRIS, and the development of a new room-temperature-magnetmore » 18 GHz ECRIS, HIISI.« less

ION SOURCE

DOEpatents

Martina, E.F.

1958-04-22

An improved ion source particularly adapted to provide an intense beam of ions with minimum neutral molecule egress from the source is described. The ion source structure includes means for establishing an oscillating electron discharge, including an apertured cathode at one end of the discharge. The egress of ions from the source is in a pencil like beam. This desirable form of withdrawal of the ions from the plasma created by the discharge is achieved by shaping the field at the aperture of the cathode. A tubular insulator is extended into the plasma from the aperture and in cooperation with the electric fields at the cathode end of the discharge focuses the ions from the source,

Ion beams extraction and measurements of plasma parameters on a multi-frequencies microwaves large bore ECRIS with permanent magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nozaki, Dai; Kiriyama, Ryutaro; Takenaka, Tomoya

2012-11-06

We have developed an all-permanent magnet large bore electron cyclotron resonance ion source (ECRIS) for broad ion beam processing. The cylindrically comb-shaped magnetic field configuration is adopted for efficient plasma production and good magnetic confinement. To compensate for disadvantages of fixed magnetic configuration, a traveling wave tube amplifier (TWTA) is used. In the comb-shaped ECRIS, it is difficult to achieve controlling ion beam profiles in the whole inside the chamber by using even single frequency-controllable TWTA (11-13GHz), because of large bore size with all-magnets. We have tried controlling profiles of plasma parameters and then those of extracted ion beams bymore » launching two largely different frequencies simultaneously, i.e., multi-frequencies microwaves. Here we report ion beam profiles and corresponding plasma parameters under various experimental conditions, dependence of ion beams against extraction voltages, and influence of different electrode positions on the electron density profile.« less

Magnetic field design for a Penning ion source for a 200 keV electrostatic accelerator

NASA Astrophysics Data System (ADS)

Fathi, A.; Feghhi, S. A. H.; Sadati, S. M.; Ebrahimibasabi, E.

2017-04-01

In this study, the structure of magnetic field for a Penning ion source has been designed and constructed with the use of permanent magnets. The ion source has been designed and constructed for a 200 keV electrostatic accelerator. With using CST Studio Suite, the magnetic field profile inside the ion source was simulated and an appropriate magnetic system was designed to improve particle confinement. Designed system consists of two ring magnets with 9 mm distance from each other around the anode. The ion source was constructed and the cylindrical magnet and designed magnetic system were tested on the ion source. The results showed that the ignition voltage for ion source with the designed magnetic system is almost 300 V lower than the ion source with the cylindrical magnet. Better particle confinement causes lower voltage discharge to occur.

Insertion compounds and composites made by ball milling for advanced sodium-ion batteries

PubMed Central

Zhang, Biao; Dugas, Romain; Rousse, Gwenaelle; Rozier, Patrick; Abakumov, Artem M.; Tarascon, Jean-Marie

2016-01-01

Sodium-ion batteries have been considered as potential candidates for stationary energy storage because of the low cost and wide availability of Na sources. However, their future commercialization depends critically on control over the solid electrolyte interface formation, as well as the degree of sodiation at the positive electrode. Here we report an easily scalable ball milling approach, which relies on the use of metallic sodium, to prepare a variety of sodium-based alloys, insertion layered oxides and polyanionic compounds having sodium in excess such as the Na4V2(PO4)2F3 phase. The practical benefits of preparing sodium-enriched positive electrodes as reservoirs to compensate for sodium loss during solid electrolyte interphase formation are demonstrated by assembling full C/P′2-Na1[Fe0.5Mn0.5]O2 and C/‘Na3+xV2(PO4)2F3' sodium-ion cells that show substantial increases (>10%) in energy storage density. Our findings may offer electrode design principles for accelerating the development of the sodium-ion technology. PMID:26777573

Versatile plasma ion source with an internal evaporator

NASA Astrophysics Data System (ADS)

Turek, M.; Prucnal, S.; Drozdziel, A.; Pyszniak, K.

2011-04-01

A novel construction of an ion source with an evaporator placed inside a plasma chamber is presented. The crucible is heated to high temperatures directly by arc discharge, which makes the ion source suitable for substances with high melting points. The compact ion source enables production of intense ion beams for wide spectrum of solid elements with typical separated beam currents of ˜100-150 μA for Al +, Mn +, As + (which corresponds to emission current densities of 15-25 mA/cm 2) for the extraction voltage of 25 kV. The ion source works for approximately 50-70 h at 100% duty cycle, which enables high ion dose implantation. The typical power consumption of the ion source is 350-400 W. The paper presents detailed experimental data (e.g. dependences of ion currents and anode voltages on discharge and filament currents and magnetic flux densities) for Cr, Fe, Al, As, Mn and In. The discussion is supported by results of Monte Carlo method based numerical simulation of ionisation in the ion source.

Industrial ion source technology

NASA Technical Reports Server (NTRS)

Kaufman, H. R.

1976-01-01

A 30 cm electron bombardment ion source was designed and fabricated for micromachining and sputtering applications. This source has a multipole magnetic field that employs permanent magnets between permeable pole pieces. An average ion current density of 1 ma/sq cm with 500 eV argon ions was selected as a design operating condition. The ion beam at this operating condition was uniform and well collimated, with an average variation of plus or minus 5 percent over the center 20 cm of the beam at distances up to 30 cm from the ion source. A variety of sputtering applications were undertaken with a small 10 cm ion source to better understand the ion source requirements in these applications. The results of these experimental studies are also included.

Neutralization of an ion beam from the end-Hall ion source by a plasma electron source based on a discharge in crossed E × H fields

NASA Astrophysics Data System (ADS)

Dostanko, A. P.; Golosov, D. A.

2009-10-01

The possibility of using a plasma electron source (PES) with a discharge in crossed E × H field for compensating the ion beam from an end-Hall ion source (EHIS) is analyzed. The PES used as a neutralizer is mounted in the immediate vicinity of the EHIS ion generation and acceleration region at 90° to the source axis. The behavior of the discharge and emission parameters of the EHIS is determined for operation with a filament neutralizer and a plasma electron source. It is found that the maximal discharge current from the ion source attains a value of 3.8 A for operation with a PES and 4 A for operation with a filament compensator. It is established that the maximal discharge current for the ion source strongly depends on the working gas flow rate for low flow rates (up to 10 ml/min) in the EHIS; for higher flow rates, the maximum discharge current in the EHIS depends only on the emissivity of the PES. Analysis of the emission parameters of EHISs with filament and plasma neutralizers shows that the ion beam current and the ion current density distribution profile are independent of the type of the electron source and the ion current density can be as high as 0.2 mA/cm2 at a distance of 25 cm from the EHIS anode. The balance of currents in the ion source-electron source system is considered on the basis of analysis of operation of EHISs with various sources of electrons. It is concluded that the neutralization current required for operation of an ion source in the discharge compensation mode must be equal to or larger than the discharge current of the ion source. The use of PES for compensating the ion beam from an end-Hall ion source proved to be effective in processes of ion-assisted deposition of thin films using reactive gases like O2 or N2. The application of the PES technique makes it possible to increase the lifetime of the ion-assisted deposition system by an order of magnitude (the lifetime with a Ti cathode is at least 60 h and is limited by the replacement life of the deposited cathode insertion).

Low energy spread ion source with a coaxial magnetic filter

DOEpatents

Leung, Ka-Ngo; Lee, Yung-Hee Yvette

2000-01-01

Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as ion projection lithography (IPL) and radioactive ion beam production. The addition of a radially extending magnetic filter consisting of a pair of permanent magnets to the multicusp source reduces the energy spread considerably due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. A coaxial multicusp ion source designed to further reduce the energy spread utilizes a cylindrical magnetic filter to achieve a more uniform axial plasma potential distribution. The coaxial magnetic filter divides the source chamber into an outer annular discharge region in which the plasma is produced and a coaxial inner ion extraction region into which the ions radially diffuse but from which ionizing electrons are excluded. The energy spread in the coaxial source has been measured to be 0.6 eV. Unlike other ion sources, the coaxial source has the capability of adjusting the radial plasma potential distribution and therefore the transverse ion temperature (or beam emittance).

Ion cyclotron resonance cell

DOEpatents

Weller, Robert R.

1995-01-01

An ion cyclotron resonance cell having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions.

Breakthrough in 4π ion emission mechanism understanding in plasma focus devices

PubMed Central

Sohrabi, Mehdi; Zarinshad, Arefe; Habibi, Morteza

2016-01-01

Ion emission angular distribution mechanisms in plasma focus devices (PFD) have not yet been well developed and understood being due to the lack of an efficient wide-angle ion distribution image detection system to characterize a PFD space in detail. Present belief is that the acceleration of ions points from “anode top” upwards in forward direction within a small solid angle. A breakthrough is reported in this study, by mega-size position-sensitive polycarbonate ion image detection systems invented, on discovery of 4π ion emission from the “anode top” in a PFD space after plasma pinch instability and radial run-away of ions from the “anode cathodes array” during axial acceleration of plasma sheaths before the radial phase. These two ion emission source mechanisms behave respectively as a “Point Ion Source” and a “Line Ion Source” forming “Ion Cathode Shadows” on mega-size detectors. We believe that the inventions and discoveries made here will open new horizons for advanced ion emission studies towards better mechanisms understanding and in particular will promote efficient applications of PFDs in medicine, science and technology. PMID:27941832

Fourth-generation plasma immersion ion implantation and deposition facility for hybrid surface modification layer fabrication.

PubMed

Wang, Langping; Huang, Lei; Xie, Zhiwen; Wang, Xiaofeng; Tang, Baoyin

2008-02-01

The fourth-generation plasma immersion ion implantation and deposition (PIIID) facility for hybrid and batch treatment was built in our laboratory recently. Comparing with our previous PIIID facilities, several novel designs are utilized. Two multicathode pulsed cathodic arc plasma sources are fixed on the chamber wall symmetrically, which can increase the steady working time from 6 h (the single cathode source in our previous facilities) to about 18 h. Meanwhile, the inner diameter of the pulsed cathodic arc plasma source is increased from the previous 80 to 209 mm, thus, large area metal plasma can be obtained by the source. Instead of the simple sample holder in our previous facility, a complex revolution-rotation sample holder composed of 24 shafts, which can rotate around its axis and adjust its position through revolving around the center axis of the vacuum chamber, is fixed in the center of the vacuum chamber. In addition, one magnetron sputtering source is set on the chamber wall instead of the top cover in the previous facility. Because of the above characteristic, the PIIID hybrid process involving ion implantation, vacuum arc, and magnetron sputtering deposition can be acquired without breaking vacuum. In addition, the PIIID batch treatment of cylinderlike components can be finished by installing these components on the rotating shafts on the sample holder.

Discovery of Suprathermal Fe+ in and near Earth's Magnetosphere

NASA Astrophysics Data System (ADS)

Christon, S. P.; Hamilton, D. C.; Plane, J. M. C.; Mitchell, D. G.; Grebowsky, J. M.; Spjeldvik, W. N.; Nylund, S. R.

2017-12-01

Suprathermal (87-212 keV/e) singly charged iron, Fe+, has been observed in and near Earth's equatorial magnetosphere using long-term ( 21 years) Geotail/STICS ion composition data. Fe+ is rare compared to dominant suprathermal solar wind and ionospheric origin heavy ions. Earth's suprathermal Fe+ appears to be positively associated with both geomagnetic and solar activity. Three candidate lower-energy sources are examined for relevance: ionospheric outflow of Fe+ escaped from ion layers altitude, charge exchange of nominal solar wind Fe+≥7, and/or solar wind transported inner source pickup Fe+ (likely formed by solar wind Fe+≥7 interaction with near sun interplanetary dust particles, IDPs). Semi-permanent ionospheric Fe+ layers form near 100 km altitude from the tons of IDPs entering Earth's atmosphere daily. Fe+ scattered from these layers is observed up to 1000 km altitude, likely escaping in strong ionospheric outflows. Using 26% of STICS's magnetosphere-dominated data at low-to-moderate geomagnetic activity levels, we demonstrate that solar wind Fe charge exchange secondaries are not an obvious Fe+ source then. Earth flyby and cruise data from Cassini/CHEMS, a nearly identical instrument, show that inner source pickup Fe+ is likely not important at suprathermal energies. Therefore, lacking any other candidate sources, it appears that ionospheric Fe+ constitutes at least an important portion of Earth's suprathermal Fe+, comparable to observations at Saturn where ionospheric origin suprathermal Fe+ has also been observed.

High-field neutral beam injection for improving the Q of a gas dynamic trap-based fusion neutron source

NASA Astrophysics Data System (ADS)

Zeng, Qiusun; Chen, Dehong; Wang, Minghuang

2017-12-01

In order to improve the fusion energy gain (Q) of a gas dynamic trap (GDT)-based fusion neutron source, a method in which the neutral beam is obliquely injected at a higher magnetic field position rather than at the mid-plane of the GDT is proposed. This method is beneficial for confining a higher density of fast ions at the turning point in the zone with a higher magnetic field, as well as obtaining a higher mirror ratio by reducing the mid-plane field rather than increasing the mirror field. In this situation, collision scattering loss of fast ions with higher density will occur and change the confinement time, power balance and particle balance. Using an updated calculation model with high-field neutral beam injection for a GDT-based fusion neutron source conceptual design, we got four optimal design schemes for a GDT-based fusion neutron source in which Q was improved to two- to three-fold compared with a conventional design scheme and considering the limitation for avoiding plasma instabilities, especially the fire-hose instability. The distribution of fast ions could be optimized by building a proper magnetic field configuration with enough space for neutron shielding and by multi-beam neutral particle injection at different axial points.

Coupling of an applied field magnetically insulated ion diode to a high power magnetically insulated transmission line system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maenchen, J.E.

1983-01-01

The coupling of energy from a high power pulsed accelerator through a long triplate magnetically insulated transmission line (MITL) in vacuum to an annular applied magnetic field insulated extraction ion diode is examined. The narrow power transport window and the wave front erosion of the MITL set stringent impedance history conditions on the diode load. A new ion diode design developed to satisfy these criteria with marginal electron insulation is presented. The LION accelerator is used to provide a positive polarity 1.5 MV, 350 kA, 40 ns FWHM pulse with a 30 kA/ns current rate from a triplate MITL source.more » A transition converts the triplate into a cylindrical cross section which flares into the ion diode load. Extensive current and voltage measurements performed along this structure and on the extracted ion beam provide conclusive evidence that the self insulation condition of the MITL is maintained in the transition by current loss alone. The ion diode utilizes a radial magnetic field between a grounded cathode annular emission tip and a disk anode. A 50 cm/sup 2/ dielectric/metal anode area serves as the ion plasma source subject to direct electron bombardment from the opposing cathode tip under marginal magnetic insulation conditions. The ions extracted cross the radial magnetic field and exit the diode volume as an annular cross section beam of peak current about 100 kA. The diode current gradually converts from the initial electron flow to nearly 100% ion current af« less

Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source.

PubMed

Kondo, K; Yamamoto, T; Sekine, M; Okamura, M

2012-02-01

The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (∼100 μA) with high charge (∼10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

Laser ion source for isobaric heavy ion collider experiment.

PubMed

Kanesue, T; Kumaki, M; Ikeda, S; Okamura, M

2016-02-01

Heavy-ion collider experiment in isobaric system is under investigation at Relativistic Heavy Ion Collider. For this experiment, ion source is required to maximize the abundance of the intended isotope. The candidate of the experiment is (96)Ru + (96)Zr. Since the natural abundance of particular isotope is low and composition of isotope from ion source depends on the composites of the target, an isotope enriched material may be needed as a target. We studied the performance of the laser ion source required for the experiment for Zr ions.

A relative quantitative positive/negative ion switching method for untargeted lipidomics via high resolution LC-MS/MS from any biological source

PubMed Central

Breitkopf, Susanne B.; Ricoult, Stéphane J. H.; Yuan, Min; Xu, Ying; Peake, David A.; Manning, Brendan D.

2017-01-01

Introduction Advances in high-resolution mass spectrometry have created renewed interest for studying global lipid biochemistry in disease and biological systems. Objectives Here, we present an untargeted 30 min. LC-MS/MS platform that utilizes positive/negative polarity switching to perform unbiased data dependent acquisitions (DDA) via higher energy collisional dissociation (HCD) fragmentation to profile more than 1000–1500 lipid ions mainly from methyl-tert-butyl ether (MTBE) or chloroform:methanol extractions. Methods The platform uses C18 reversed-phase chromatography coupled to a hybrid QExactive Plus/HF Orbitrap mass spectrometer and the entire procedure takes ~10 h from lipid extraction to identification/quantification for a data set containing 12 samples (~4 h for a single sample). Lipids are identified by both accurate precursor ion mass and fragmentation features and quantified using Lipid-Search and Elements software. Results Using this approach, we are able to profile intact lipid ions from up to 18 different main lipid classes and 66 subclasses. We show several studies from different biological sources, including cultured cancer cells, resected tissues from mice such as lung and breast tumors and biological fluids such as plasma and urine. Conclusions Using mouse embryonic fibroblasts, we showed that TSC2−/− KD significantly abrogates lipid biosynthesis and that rapamycin can rescue triglyceride (TG) lipids and we show that SREBP−/− shuts down lipid biosynthesis significantly via mTORC1 signaling pathways. We show that in mouse EGFR driven lung tumors, a large number of TGs and phosphatidylmethanol (PMe) lipids are elevated while some phospholipids (PLs) show some of the largest decrease in lipid levels from ~ 2000 identified lipid ions. In addition, we identified more than 1500 unique lipid species from human blood plasma. PMID:28496395

Liquid metal ion source and alloy for ion emission of multiple ionic species

DOEpatents

Clark, Jr., William M.; Utlaut, Mark W.; Wysocki, Joseph A.; Storms, Edmund K.; Szklarz, Eugene G.; Behrens, Robert G.; Swanson, Lynwood W.; Bell, Anthony E.

1987-06-02

A liquid metal ion source and alloy for the simultaneous ion evaporation of arsenic and boron, arsenic and phosphorus, or arsenic, boron and phosphorus. The ionic species to be evaporated are contained in palladium-arsenic-boron and palladium-arsenic-boron-phosphorus alloys. The ion source, including an emitter means such as a needle emitter and a source means such as U-shaped heater element, is preferably constructed of rhenium and tungsten, both of which are readily fabricated. The ion sources emit continuous beams of ions having sufficiently high currents of the desired species to be useful in ion implantation of semiconductor wafers for preparing integrated circuit devices. The sources are stable in operation, experience little corrosion during operation, and have long operating lifetimes.

An investigation of the ionospheric D region at sunrise

NASA Technical Reports Server (NTRS)

Turco, R. P.; Sechrist, C. F., Jr.

1970-01-01

The growth over sunrise of the C and D layers of the ionosphere is investigated. The model which is analyzed includes the negative ion species O(-), O2(-), O3(-), O4(-), NO3(-), CO3(-), and CO4(-). Ionization sources due to galactic cosmic rays, precipitated electrons, ionization of NO by scattered Lyman alpha radiation, and the direct solar radiation ionization are also included. The photodetachment of most of the negative ions is discussed, as well as the time variation of these parameters. The time variations of the electron, negative ion, and positive ion densities are calculated over sunrise. From these data, the mesospheric C and D layer development is plotted. Several model parameters are varied until the best agreement with experimentally determined electron densities is obtained. The results are discussed in light of several atmospheric parameters including the O and NO concentrations and the electron-ion recombination coefficient.

Improvement of a plasma uniformity of the 2nd ion source of KSTAR neutral beam injector.

PubMed

Jeong, S H; Kim, T S; Lee, K W; Chang, D H; In, S R; Bae, Y S

2014-02-01

The 2nd ion source of KSTAR (Korea Superconducting Tokamak Advanced Research) NBI (Neutral Beam Injector) had been developed and operated since last year. A calorimetric analysis revealed that the heat load of the back plate of the ion source is relatively higher than that of the 1st ion source of KSTAR NBI. The spatial plasma uniformity of the ion source is not good. Therefore, we intended to identify factors affecting the uniformity of a plasma density and improve it. We estimated the effects of a direction of filament current and a magnetic field configuration of the plasma generator on the plasma uniformity. We also verified that the operation conditions of an ion source could change a uniformity of the plasma density of an ion source.

Corona discharge ion mobility spectrometry with orthogonal acceleration time of flight mass spectrometry for monitoring of volatile organic compounds.

PubMed

Sabo, Martin; Matejčík, Štefan

2012-06-19

We demonstrate the application of corona discharge ion mobility spectrometry with orthogonal acceleration time of flight mass spectrometry (CD IMS-oaTOF) for volatile organic compounds (VOCs) monitoring. Two-dimensional (2D) IMS-oaTOF spectra of VOCs were recorded in nearly real time. The corona discharge atmospheric pressure chemical ionization (APCI) source was operated in positive mode in nitrogen and air. The CD ion source generates in air H(3)O(+)(H(2)O)(n) and NO(+). The NO(+) offers additional possibility for selective ionization and for an increase of the sensitivity of monoaromatic compounds. In addition to H(3)O(+)(H(2)O)(n) and NO(+), we have carried out ionization of VOCs using acetone as dopant gas ((CH(3))(2)COH(+)). Sixteen model VOCs (tetrahydrofuran, butanol, n-propanol, iso-propano, acetone, methanol, ethanol, toluene, benzene, amomnia, dioxan, triethylamine, acetonitrile, formaldehyde, m-xylene, 2,2,2-trifluoroethylamine) were tested using these ionization techniques.

Study of negative ion transport phenomena in a plasma source

NASA Astrophysics Data System (ADS)

Riz, D.; Paméla, J.

1996-07-01

NIETZSCHE (Negative Ions Extraction and Transport ZSimulation Code for HydrogEn species) is a negative ion (NI) transport code developed at Cadarache. This code calculates NI trajectories using a 3D Monte-Carlo technique, taking into account the main destruction processes, as well as elastic collisions (H-/H+) and charge exchanges (H-/H0). It determines the extraction probability of a NI created at a given position. According to the simulations, we have seen that in the case of volume production, only NI produced close to the plasma grid (PG) can be extracted. Concerning the surface production, we have studied how NI produced on the PG and accelerated by the plasma sheath backward into the source could be extracted. We demonstrate that elastic collisions and charge exchanges play an important role, which in some conditions dominates the magnetic filter effect, which acts as a magnetic mirror. NI transport in various conditions will be discussed: volume/surface production, high/low plasmas density, tent filter/transverse filter.

Research progress on ionic plasmas generated in an intense hydrogen negative ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeiri, Y., E-mail: takeiri@nifs.ac.jp; Tsumori, K.; Nagaoka, K.

2015-04-08

Characteristics of ionic plasmas, observed in a high-density hydrogen negative ion source, are investigated with a multi-diagnostics system. The ionic plasma, which consists of hydrogen positive- and negative-ions with a significantly low-density of electrons, is generated in the ion extraction region, from which the negative ions are extracted through the plasma grid. The negative ion density, i.e., the ionic plasma density, as high as the order of 1×10{sup 17}m{sup −3}, is measured with cavity ring-down spectroscopy, while the electron density is lower than 1×10{sup 16}m{sup −3}, which is confirmed with millimeter-wave interferometer. Reduction of the negative ion density is observedmore » at the negative ion extraction, and at that time the electron flow into the ionic plasma region is observed to conserve the charge neutrality. Distribution of the plasma potential is measured in the extraction region in the direction normal to the plasma grid surface with a Langmuir probe, and the results suggest that the sheath is formed at the plasma boundary to the plasma grid to which the bias voltage is applied. The beam extraction should drive the negative ion transport in the ionic plasma across the sheath formed on the extraction surface. Larger reduction of the negative ions at the beam extraction is observed in a region above the extraction aperture on the plasma grid, which is confirmed with 2D image measurement of the Hα emission and cavity ring-down spectroscopy. The electron distribution is also measured near the plasma grid surface. These various properties observed in the ionic plasma are discussed.« less

Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos; Van Berkel, Gary J

2011-01-01

Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpinemore » was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.« less

Laser ion source with solenoid field

NASA Astrophysics Data System (ADS)

Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; Okamura, Masahiro

2014-11-01

Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. The laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 1011, which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.

Electrostatic shape-shifting ion optics

DOEpatents

Dahl, David A.; Scott, Jill R.; Appelhans, Anthony D.

2006-05-02

Electrostatic shape-shifting ion optics includes an outer electrode that defines an interior region between first and second opposed open ends. A first inner electrode is positioned within the interior region of the outer electrode at about the first open end. A second inner electrode is positioned within the interior region of the outer electrode at about the second open end. A first end cap electrode is positioned at about a first open end of the first inner electrode so that the first end cap electrode substantially encloses the first open end of the first inner electrode. A second end cap electrode is positioned at about a second open end of the second inner electrode so that the second end cap electrode substantially encloses the second open end of the second inner electrode. A voltage source operatively connected to each of the electrodes applies voltage functions to each of the electrodes to produce an electric field within an interior space enclosed by the electrodes.

Microchip and wedge ion funnels and planar ion beam analyzers using same

DOEpatents

Shvartsburg, Alexandre A; Anderson, Gordon A; Smith, Richard D

2012-10-30

Electrodynamic ion funnels confine, guide, or focus ions in gases using the Dehmelt potential of oscillatory electric field. New funnel designs operating at or close to atmospheric gas pressure are described. Effective ion focusing at such pressures is enabled by fields of extreme amplitude and frequency, allowed in microscopic gaps that have much higher electrical breakdown thresholds in any gas than the macroscopic gaps of present funnels. The new microscopic-gap funnels are useful for interfacing atmospheric-pressure ionization sources to mass spectrometry (MS) and ion mobility separation (IMS) stages including differential IMS or FAIMS, as well as IMS and MS stages in various configurations. In particular, "wedge" funnels comprising two planar surfaces positioned at an angle and wedge funnel traps derived therefrom can compress ion beams in one dimension, producing narrow belt-shaped beams and laterally elongated cuboid packets. This beam profile reduces the ion density and thus space-charge effects, mitigating the adverse impact thereof on the resolving power, measurement accuracy, and dynamic range of MS and IMS analyzers, while a greater overlap with coplanar light or particle beams can benefit spectroscopic methods.

Detecting negative ions on board small satellites

NASA Astrophysics Data System (ADS)

Lepri, S. T.; Raines, J. M.; Gilbert, J. A.; Cutler, J.; Panning, M.; Zurbuchen, T. H.

2017-04-01

Recent measurements near comets, planets, and their satellites have shown that heavy ions, energetic neutral atoms, molecular ions, and charged dust contain a wealth of information about the origin, evolution, and interaction of celestial bodies with their space environment. Using highly sensitive plasma instruments, positively charged heavy ions have been used to trace exospheric and surface composition of comets, planets, and satellites as well as the composition of interplanetary and interstellar dust. While positive ions dominate throughout the heliosphere, negative ions are also produced from surface interactions. In fact, laboratory experiments have shown that oxygen released from rocky surfaces is mostly negatively charged. Negative ions and negatively charged nanograins have been detected with plasma electron analyzers in several different environments (e.g., by Cassini and Rosetta), though more extensive studies have been challenging without instrumentation dedicated to negative ions. We discuss an adaptation of the Fast Imaging Plasma Spectrometer (FIPS) flown on MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) for the measurement of negatively charged particles. MESSENGER/FIPS successfully measured the plasma environment of Mercury from 2011 until 2015, when the mission ended, and has been used to map multiple ion species (H+ through Na+ and beyond) throughout Mercury's space environment. Modifications to the existing instrument design fits within a 3U CubeSat volume and would provide a low mass, low power instrument, ideal for future CubeSat or distributed sensor missions seeking, for the first time, to characterize the contribution of negative particles in the heliospheric plasmas near the planets, moons, comets, and other sources.

High Resolution Studies of the Origins of Polyatomic Ions in Inductively Coupled Plasma-Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferguson, Jill Wisnewski

2006-01-01

The inductively coupled plasma (ICP) is an atmospheric pressure ionization source. Traditionally, the plasma is sampled via a sampler cone. A supersonic jet develops behind the sampler, and this region is pumped down to a pressure of approximately one Torr. A skimmer cone is located inside this zone of silence to transmit ions into the mass spectrometer. The position of the sampler and skimmer cones relative to the initial radiation and normal analytical zones of the plasma is key to optimizing the useful analytical signal [1]. The ICP both atomizes and ionizes the sample. Polyatomic ions form through ion-molecule interactionsmore » either in the ICP or during ion extraction [l]. Common polyatomic ions that inhibit analysis include metal oxides (MO +), adducts with argon, the gas most commonly used to make up the plasma, and hydride species. While high resolution devices can separate many analytes from common interferences, this is done at great cost in ion transmission efficiency--a loss of 99% when using high versus low resolution on the same instrument [2]. Simple quadrupole devices, which make up the bulk of ICP-MS instruments in existence, do not present this option. Therefore, if the source of polyatomic interferences can be determined and then manipulated, this could potentially improve the figures of merit on all ICP-MS devices, not just the high resolution devices often utilized to study polyatomic interferences.« less

Ion-source modeling and improved performance of the CAMS high-intensity Cs-sputter ion source

NASA Astrophysics Data System (ADS)

Brown, T. A.; Roberts, M. L.; Southon, J. R.

2000-10-01

The interior of the high-intensity Cs-sputter source used in routine operations at the Center for Accelerator Mass Spectrometry (CAMS) has been computer modeled using the program NEDLab, with the aim of improving negative ion output. Space charge effects on ion trajectories within the source were modeled through a successive iteration process involving the calculation of ion trajectories through Poisson-equation-determined electric fields, followed by calculation of modified electric fields incorporating the charge distribution from the previously calculated ion trajectories. The program has several additional features that are useful in ion source modeling: (1) averaging of space charge distributions over successive iterations to suppress instabilities, (2) Child's Law modeling of space charge limited ion emission from surfaces, and (3) emission of particular ion groups with a thermal energy distribution and at randomized angles. The results of the modeling effort indicated that significant modification of the interior geometry of the source would double Cs + ion production from our spherical ionizer and produce a significant increase in negative ion output from the source. The results of the implementation of the new geometry were found to be consistent with the model results.

Dual mode ion mobility spectrometer and method for ion mobility spectrometry

DOEpatents

Scott, Jill R [Idaho Falls, ID; Dahl, David A [Idaho Falls, ID; Miller, Carla J [Idaho Falls, ID; Tremblay, Paul L [Idaho Falls, ID; McJunkin, Timothy R [Idaho Falls, ID

2007-08-21

Ion mobility spectrometer apparatus may include an ion interface that is operable to hold positive and negative ions and to simultaneously release positive and negative ions through respective positive and negative ion ports. A first drift chamber is operatively associated with the positive ion port of the ion interface and encloses an electric field therein. A first ion detector operatively associated with the first drift chamber detects positive ions from the first drift chamber. A second drift chamber is operatively associated with the negative ion port of the ion interface and encloses an electric field therein. A second ion detector operatively associated with the second drift chamber detects negative ions from said second drift chamber.

Development of a plug-type IMS-MS instrument and its applications in resolving problems existing in in-situ detection of illicit drugs and explosives by IMS.

PubMed

Du, Zhenxia; Sun, Tangqiang; Zhao, Jianan; Wang, Di; Zhang, Zhongxia; Yu, Wenlian

2018-07-01

Ion mobility spectrometry (IMS) which acts as a rapid analysis technique is widely used in the field detection of illicit drugs and explosives. Due to limited separation abilities of the pint-sized IMS challenges and problems still exist regarding high false positive and false negative responses due to the interference of the matrix. In addition, the gas-phase ion chemistry and special phenomena in the IMS spectra, such one substance showing two peaks, were not identified unambiguously. In order to explain or resolve these questions, in this paper, an ion mobility spectrometry was coupled to a mass spectrometry (IMS-MS). A commercial IMS is embedded in a custom-built ion chamber shell was attached to the mass spectrometer. The faraday plate of IMS was fabricated with a hole for the ions to passing through to the mass spectrometer. The ion transmission efficiency of IMS-MS was optimized by optimizing the various parameters, especially the distance between the faraday plate and the cone of mass spectrum. This design keeps the integrity of the two original instruments and the mass spectrometry still works with multimode ionization source (i.e., IMS-MS, ESI-MS, APCI-MS modes). The illicit drugs and explosive samples were analyzed by the IMS-MS with 63 Ni source. The results showed that the IMS-MS is of high sensitivity. The ionization mechanism of the illicit drug and explosive samples with 63 Ni source were systematically studied. In addition, the interferent which interfered the detection of cocaine was identified as dibutyl phthalate (DBP) by this platform. The reason why the acetone solution of amphetamine showed two peaks was explained. Copyright © 2018 Elsevier B.V. All rights reserved.

Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lettry J.; Alessi J.; Faircloth, D.

2012-02-23

Linac4 accelerator of Centre Europeen de Recherches Nucleaires is under construction and a RF-driven H{sup -} ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible aftermore » extended operation periods. A metallurgical investigation of an ISIS ion source is presented. The origin of the deformation is twofold: Molybdenum sputtering by cesium ions digs few tenths of mm cavities while a growth of molybdenum is observed in the immediate vicinity. The molybdenum growth under hydrogen atmosphere is hard and loosely bound to the bulk. It is, therefore, likely to peel off and be transported within the plasma volume. The observation of the cathode, anode, and extraction electrodes of the magnetron source operated at BNL for two years are presented. A beam simulation of H{sup -}, electrons, and Cs{sup -} ions was performed with the IBSimu code package to qualitatively explain the observations. This paper describes the operation conditions of the ion sources and discusses the metallurgical analysis and beam simulation results.« less

Investigation of ISIS and Brookhaven National Laboratory ion source electrodes after extended operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lettry, J.; Gerardin, A.; Pereira, H.

2012-02-15

Linac4 accelerator of Centre Europeen de Recherches Nucleaires is under construction and a RF-driven H{sup -} ion source is being developed. The beam current requirement for Linac4 is very challenging: 80 mA must be provided. Cesiated plasma discharge ion sources such as Penning or magnetron sources are also potential candidates. Accelerator ion sources must achieve typical reliability figures of 95% and above. Investigating and understanding the underlying mechanisms involved with source failure or ageing is critical when selecting the ion source technology. Plasma discharge driven surface ion sources rely on molybdenum cathodes. Deformation of the cathode surfaces is visible aftermore » extended operation periods. A metallurgical investigation of an ISIS ion source is presented. The origin of the deformation is twofold: Molybdenum sputtering by cesium ions digs few tenths of mm cavities while a growth of molybdenum is observed in the immediate vicinity. The molybdenum growth under hydrogen atmosphere is hard and loosely bound to the bulk. It is, therefore, likely to peel off and be transported within the plasma volume. The observation of the cathode, anode, and extraction electrodes of the magnetron source operated at BNL for two years are presented. A beam simulation of H{sup -}, electrons, and Cs{sup -} ions was performed with the IBSimu code package to qualitatively explain the observations. This paper describes the operation conditions of the ion sources and discusses the metallurgical analysis and beam simulation results.« less

Ion sources for electric propulsion

NASA Technical Reports Server (NTRS)

Stuhlinger, E.

1971-01-01

Ion systems, which accelerate ions of Cs, Hg, or colloid particles by electrostatic fields, are furthest advanced and ready for application. Four kinds of ion sources have been developed: The contact ionization source for Cs as propellants, the electron bombardment source for Cs or Hg, the RF ionization source for Hg, and the hollow needle spray nozzle for colloidal glycerol particles. In each case, the ion beam must be neutralized by injection of electrons shortly behind the exit orifice to avoid adverse space charge effects.

Preliminary Tests of a Paul ion Trap as an Ion Source

NASA Astrophysics Data System (ADS)

Sadat Kiai, S. M.; Zirak, A. R.; Elahi, M.; Adlparvar, S.; Mortazavi, B. N.; Safarien, A.; Farhangi, S.; Sheibani, S.; Alhooie, S.; Khalaj, M. M. A.; Dabirzadeh, A. A.; Ruzbehani, M.; Zahedi, F.

2010-10-01

The paper reports on the design and construction of a Paul ion trap as an ion source by using an impact electron ionization technique. Ions are produced in the trap and confined for the specific time which is then extracted and detected by a Faraday cup. Especial electronic configurations are employed between the end caps, ring electrodes, electron gun and a negative voltage for the detector. This configuration allows a constant low level of pure ion source between the pulsed confined ion sources. The present experimental results are based on the production and confinement of Argon ions with good stability and repeatability, but in principle, the technique can be used for various Argon like ions.

Laser ion source with solenoid field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanesue, Takeshi, E-mail: tkanesue@bnl.gov; Okamura, Masahiro; Fuwa, Yasuhiro

2014-11-10

Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. The laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 10{sup 11}, which was provided by a single 1 J Nd-YAGmore » laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.« less

Laser ion source with solenoid field

DOE PAGES

Kanesue, Takeshi; Fuwa, Yasuhiro; Kondo, Kotaro; ...

2014-11-12

Pulse length extension of highly charged ion beam generated from a laser ion source is experimentally demonstrated. In this study, the laser ion source (LIS) has been recognized as one of the most powerful heavy ion source. However, it was difficult to provide long pulse beams. By applying a solenoid field (90 mT, 1 m) at plasma drifting section, a pulse length of carbon ion beam reached 3.2 μs which was 4.4 times longer than the width from a conventional LIS. The particle number of carbon ions accelerated by a radio frequency quadrupole linear accelerator was 1.2 × 10 11,more » which was provided by a single 1 J Nd-YAG laser shot. A laser ion source with solenoid field could be used in a next generation heavy ion accelerator.« less

Recent Development of IMP LECR3 Ion Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Z.M.; Zhao, H.W.; Li, J.Y.

2005-03-15

18GHz microwave has been fed to the LECR3 ion source to produce intense highly charged ion beams although this ion source was designed for 14.5GHz. Then 1.1 emA Ar8+ and 325 e{mu}A Ar11+ were obtained at 18GHz. During the source running for atomic physics experiment, some higher charge state ion beams such as Ar17+ and Ar18+ were detected and have been validated by atomic physics method. Furthermore, a few special gases, e.g. SiH4 and SF6, were tested on LECR3 ion source to produce required ion beams to satisfy the requirements of atomic physics experiments.

Atmospheric pressure ionization-tandem mass spectrometry of the phenicol drug family.

PubMed

Alechaga, Élida; Moyano, Encarnación; Galceran, M Teresa

2013-11-01

In this work, the mass spectrometry behaviour of the veterinary drug family of phenicols, including chloramphenicol (CAP) and its related compounds thiamphenicol (TAP), florfenicol (FF) and FF amine (FFA), was studied. Several atmospheric pressure ionization sources, electrospray (ESI), atmospheric pressure chemical ionization and atmospheric pressure photoionization were compared. In all atmospheric pressure ionization sources, CAP, TAP and FF were ionized in both positive and negative modes; while for the metabolite FFA, only positive ionization was possible. In general, in positive mode, [M + H](+) dominated the mass spectrum for FFA, while the other compounds, CAP, TAP and FF, with lower proton affinity showed intense adducts with species present in the mobile phase. In negative mode, ESI and atmospheric pressure photoionization showed the deprotonated molecule [M-H](-), while atmospheric pressure chemical ionization provided the radical molecular ion by electron capture. All these ions were characterized by tandem mass spectrometry using the combined information obtained by multistage mass spectrometry and high-resolution mass spectrometry in a quadrupole-Orbitrap instrument. In general, the fragmentation occurred via cyclization and losses or fragmentation of the N-(alkyl)acetamide group, and common fragmentation pathways were established for this family of compounds. A new chemical structure for the product ion at m/z 257 for CAP, on the basis of the MS(3) and MS(4) spectra is proposed. Thermally assisted ESI and selected reaction monitoring are proposed for the determination of these compounds by ultra high-performance liquid chromatography coupled to tandem mass spectrometry, achieving instrumental detection limits down to 0.1 pg. Copyright © 2013 John Wiley & Sons, Ltd.

Liquid metal ion source assembly for external ion injection into an electron string ion source (ESIS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Segal, M. J., E-mail: mattiti@gmail.com; University of Cape Town, Rondebosch, Cape Town 7700; Bark, R. A.

An assembly for a commercial Ga{sup +} liquid metal ion source in combination with an ion transportation and focusing system, a pulse high-voltage quadrupole deflector, and a beam diagnostics system has been constructed in the framework of the iThemba LABS (Cape Town, South Africa)—JINR (Dubna, Russia) collaboration. First, results on Ga{sup +} ion beam commissioning will be presented. Outlook of further experiments for measurements of charge breeding efficiency in the electron string ion source with the use of external injection of Ga{sup +} and Au{sup +} ion beams will be reported as well.

Scalable integration of Li5FeO4 towards robust, high-performance lithium-ion hybrid capacitors.

PubMed

Park, Min-Sik; Lim, Young-Geun; Hwang, Soo Min; Kim, Jung Ho; Kim, Jeom-Soo; Dou, Shi Xue; Cho, Jaephil; Kim, Young-Jun

2014-11-01

Lithium-ion hybrid capacitors have attracted great interest due to their high specific energy relative to conventional electrical double-layer capacitors. Nevertheless, the safety issue still remains a drawback for lithium-ion capacitors in practical operational environments because of the use of metallic lithium. Herein, single-phase Li5FeO4 with an antifluorite structure that acts as an alternative lithium source (instead of metallic lithium) is employed and its potential use for lithium-ion capacitors is verified. Abundant Li(+) amounts can be extracted from Li5FeO4 incorporated in the positive electrode and efficiently doped into the negative electrode during the first electrochemical charging. After the first Li(+) extraction, Li(+) does not return to the Li5FeO4 host structure and is steadily involved in the electrochemical reactions of the negative electrode during subsequent cycling. Various electrochemical and structural analyses support its superior characteristics for use as a promising lithium source. This versatile approach can yield a sufficient Li(+)-doping efficiency of >90% and improved safety as a result of the removal of metallic lithium from the cell. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A hollow cathode ion source for production of primary ions for the BNL electron beam ion source.

PubMed

Alessi, James; Beebe, Edward; Carlson, Charles; McCafferty, Daniel; Pikin, Alexander; Ritter, John

2014-02-01

A hollow cathode ion source, based on one developed at Saclay, has been modified significantly and used for several years to produce all primary 1+ ions injected into the Relativistic Heavy Ion Collider Electron Beam Ion Source (EBIS) at Brookhaven. Currents of tens to hundreds of microamperes have been produced for 1+ ions of He, C, O, Ne, Si, Ar, Ti, Fe, Cu, Kr, Xe, Ta, Au, and U. The source is very simple, relying on a glow discharge using a noble gas, between anode and a solid cathode containing the desired species. Ions of both the working gas and ionized sputtered cathode material are extracted, and then the desired species is selected using an ExB filter before being transported into the EBIS trap for charge breeding. The source operates pulsed with long life and excellent stability for most species. Reliable ignition of the discharge at low gas pressure is facilitated by the use of capacitive coupling from a simple toy plasma globe. The source design, and operating experience for the various species, is presented.

Interpretation of the ion mass spectra in the mass range 25-35 obtained in the inner coma of Halley's comet by the HIS-sensor of the Giotto IMS Experiment

NASA Technical Reports Server (NTRS)

Geiss, J.; Altwegg, K.; Anders, E.; Balsiger, H.; Ip, W.-H.; Meier, A.; Neugebauer, M.; Rosenbauer, H.; Shelley, E. G.

1991-01-01

The IMS-HIS double-focussing mass spectrometer that flew on the Giotto spacecraft covered the mass per charge range from 12 to 56 (AMU/e). By comparing flight data, calibration data, and results of model calculations of the ion population in the inner coma, the absolute mass scale is established, and ions in the mass range 25 to 35 are identified. Ions resulting from protonation of molecules with high proton affinity are relatively abundant, enabling us to estimate relative source strengths for H2CO, CH3OH, HCN, and H2S, providing for the first time a positive in situ measurement of methanol. Also, upper limits for NO and some hydrocarbons are derived.

Determination and identification of malathion, ethion and dichlorovos using ion mobility spectrometry.

PubMed

Jafari, Mohammad T

2006-07-15

Positive ion mobility spectra of different organophosphorus pesticides such as malathion (s-(1,2-dicarb-ethoxyethyl) o,o-dimethyl dithiophosphate), ethion (o,o,o',o'-tetraethyl s,s'-methylene bis(phosphorodithioate)) and dichlorovos (2,2-dichlorovinyl dimethyl phosphate) have been studied in air at ambient pressure using ion mobility spectrometry method with (63)Ni ionization source. The limits of quantification (LOQs) were 1.0 x 10(-9), 1.0 x 10(-9) and 5.0 x 10(-9)g for malathion, ethion and dichlorovos, respectively. The working range of these compounds was about three orders of magnitude and the relative standard deviation (R.S.D.) of repeatability at the 5 microg ml(-1) level were all below 15%. Furthermore, in this study, the influences of IMS cell temperature on the ion mobility spectra of these compounds were investigated.

Interpretation of the ion mass spectra in the mass per charge range 25-35 amu/e obtained in the inner coma of Halley's comet by the HIS-sensor of the Giotto IMS experiment

NASA Technical Reports Server (NTRS)

Geiss, J.; Altwegg, K.; Anders, E.; Balsiger, H.; Meier, A.; Shelley, E. G.; Ip, W.-H.; Rosenbauer, H.; Neugebauer, M.

1991-01-01

The IMS-HIS double-focusing mass spectrometer that flew on the Giotto spacecraft covered the mass per charge range from 12 to 56 (amu/e). By comparing flight data, calibration data and results of model calculations of the ion population in the inner coma, the absolute mass scale is established, and ions in the mass range 25 to 35 are identified. Ions resulting from protonation of molecules with high proton affinity are relatively abundant, enabling us to estimate relative source strengths for H2CO, CH3OH, HCN, and H2S, providing for the first time a positive in situ measurement of methanol. Also, upper limits for NO and some hydrocarbons are derived.

A 1D ion species model for an RF driven negative ion source

NASA Astrophysics Data System (ADS)

Turner, I.; Holmes, A. J. T.

2017-08-01

A one-dimensional model for an RF driven negative ion source has been developed based on an inductive discharge. The RF source differs from traditional filament and arc ion sources because there are no primary electrons present, and is simply composed of an antenna region (driver) and a main plasma discharge region. However the model does still make use of the classical plasma transport equations for particle energy and flow, which have previously worked well for modelling DC driven sources. The model has been developed primarily to model the Small Negative Ion Facility (SNIF) ion source at CCFE, but may be easily adapted to model other RF sources. Currently the model considers the hydrogen ion species, and provides a detailed description of the plasma parameters along the source axis, i.e. plasma temperature, density and potential, as well as current densities and species fluxes. The inputs to the model are currently the RF power, the magnetic filter field and the source gas pressure. Results from the model are presented and where possible compared to existing experimental data from SNIF, with varying RF power, source pressure.

Detection of explosives using negative ion mobility spectrometry in air based on dopant-assisted thermal ionization.

PubMed

Shahraki, Hassan; Tabrizchi, Mahmoud; Farrokhpor, Hossein

2018-05-26

The ionization source is an essential component of most explosive detectors based on negative ion mobility spectrometry. Conventional ion sources suffer from such inherent limitations as special safety regulations on radioactive sources or generating interfering ions (for non-radioactive sources) such as corona discharge operating in the air. In this study, a new negative ion source is introduced for ion mobility spectrometry that is based on thermal ionization and operates in the air, applicable to explosives detection. Our system consists of a heating filament powered by an isolated power supply connected to negative high voltage. The ionization is assisted by doping chlorinated compounds in the gas phase using chlorinated hydrocarbons in contact with the heating element to yield Cl - reactant ions. Several chlorinated hydrocarbons are evaluated as the reagent chemicals for providing Cl- reactant ions, of which CCl 4 is identified as the best ionizing reagent. The ion source is evaluated by recording the ion mobility spectra of common explosives, including TNT, RDX, and PETN in the air. A detection limit of 150 pg is obtained for TNT. Compared to other ionization sources, the new source is found to be low-cost, simple, and long-lived, making it suited to portable explosives detection devices. Copyright © 2018 Elsevier B.V. All rights reserved.

Current density distributions and sputter marks in electron cyclotron resonance ion sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Panitzsch, Lauri; Peleikis, Thies; Boettcher, Stephan

2013-01-15

Most electron cyclotron resonance ion sources use hexapolar magnetic fields for the radial confinement of the plasma. The geometry of this magnetic structure is then-induced by charged particles-mapped onto the inner side of the plasma electrode via sputtering and deposition. The resulting structures usually show two different patterns: a sharp triangular one in the central region which in some cases is even sputtered deep into the material (referred to as thin groove or sharp structure), and a blurred but still triangular-like one in the surroundings (referred to as broad halo). Therefore, both patterns seem to have different sources. To investigatemore » their origins we replaced the standard plasma electrode by a custom-built plasma electrode acting as a planar, multi-segment current-detector. For different biased disc voltages, detector positions, and source biases (referred to the detector) we measured the electrical current density distributions in the plane of the plasma electrode. The results show a strong and sharply confined electron population with triangular shape surrounded by less intense and spatially less confined ions. Observed sputter- and deposition marks are related to the analysis of the results. Our measurements suggest that the two different patterns (thin and broad) indeed originate from different particle populations. The thin structures seem to be caused by the hot electron population while the broad marks seem to stem from the medium to highly charged ions. In this paper we present our measurements together with theoretical considerations and substantiate the conclusions drawn above. The validity of these results is also discussed.« less

Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

PubMed

Bianchi, Federico; Praplan, Arnaud P; Sarnela, Nina; Dommen, Josef; Kürten, Andreas; Ortega, Ismael K; Schobesberger, Siegfried; Junninen, Heikki; Simon, Mario; Tröstl, Jasmin; Jokinen, Tuija; Sipilä, Mikko; Adamov, Alexey; Amorim, Antonio; Almeida, Joao; Breitenlechner, Martin; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Laaksonen, Ari; Lawler, Michael J; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Tomé, António; Virtanen, Annele; Viisanen, Yrjö; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

2014-12-02

We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cuomo, J.J.; Rossnagel, S.M.; Kaufman, H.R.

The work presented in this book deals with ion beam processing for basic sputter etching of samples, for sputter deposition of thin films, for the synthesis of material in thin form, and for the modification of the properties of thin films. The ion energy range covered is from a few tens of eV to about 10,000 eV, with primary interest in the range of about 20 to 1-2 keV, where implantation of the incident ion is a minor effect. Of the types of ion sources and devices available, this book examines principally broad beam ion sources, characterized by high fluxesmore » and large work areas. These sources include the ECR ion source, the Kaufman-type single- and multiple-grid sources, gridless sources such as the Hall effect or closed-drift source, and hydrid sources such as the ionized cluster beam system.« less

Numerical Simulation of Ion Transport in a Nano-Electrospray Ion Source at Atmospheric Pressure

NASA Astrophysics Data System (ADS)

Wang, Wei; Bajic, Steve; John, Benzi; Emerson, David R.

2018-03-01

Understanding ion transport properties from the ion source to the mass spectrometer (MS) is essential for optimizing device performance. Numerical simulation helps in understanding of ion transport properties and, furthermore, facilitates instrument design. In contrast to previously reported numerical studies, ion transport simulations in a continuous injection mode whilst considering realistic space-charge effects have been carried out. The flow field was solved using Reynolds-averaged Navier-Stokes (RANS) equations, and a particle-in-cell (PIC) method was applied to solve a time-dependent electric field with local charge density. A series of ion transport simulations were carried out at different cone gas flow rates, ion source currents, and capillary voltages. A force evaluation analysis reveals that the electric force, the drag force, and the Brownian force are the three dominant forces acting on the ions. Both the experimental and simulation results indicate that cone gas flow rates of ≤250 slph (standard liter per hour) are important for high ion transmission efficiency, as higher cone gas flow rates reduce the ion signal significantly. The simulation results also show that the ion transmission efficiency reduces exponentially with an increased ion source current. Additionally, the ion loss due to space-charge effects has been found to be predominant at a higher ion source current, a lower capillary voltage, and a stronger cone gas counterflow. The interaction of the ion driving force, ion opposing force, and ion dispersion is discussed to illustrate ion transport mechanism in the ion source at atmospheric pressure. [Figure not available: see fulltext.

Numerical Simulation of Ion Transport in a Nano-Electrospray Ion Source at Atmospheric Pressure.

PubMed

Wang, Wei; Bajic, Steve; John, Benzi; Emerson, David R

2018-03-01

Understanding ion transport properties from the ion source to the mass spectrometer (MS) is essential for optimizing device performance. Numerical simulation helps in understanding of ion transport properties and, furthermore, facilitates instrument design. In contrast to previously reported numerical studies, ion transport simulations in a continuous injection mode whilst considering realistic space-charge effects have been carried out. The flow field was solved using Reynolds-averaged Navier-Stokes (RANS) equations, and a particle-in-cell (PIC) method was applied to solve a time-dependent electric field with local charge density. A series of ion transport simulations were carried out at different cone gas flow rates, ion source currents, and capillary voltages. A force evaluation analysis reveals that the electric force, the drag force, and the Brownian force are the three dominant forces acting on the ions. Both the experimental and simulation results indicate that cone gas flow rates of ≤250 slph (standard liter per hour) are important for high ion transmission efficiency, as higher cone gas flow rates reduce the ion signal significantly. The simulation results also show that the ion transmission efficiency reduces exponentially with an increased ion source current. Additionally, the ion loss due to space-charge effects has been found to be predominant at a higher ion source current, a lower capillary voltage, and a stronger cone gas counterflow. The interaction of the ion driving force, ion opposing force, and ion dispersion is discussed to illustrate ion transport mechanism in the ion source at atmospheric pressure. Graphical Abstract.

New ion source for KSTAR neutral beam injection system.

PubMed

Kim, Tae-Seong; Jeong, Seung Ho; In, Sang-Ryul

2012-02-01

The neutral beam injection system (NBI-1) of the KSTAR tokamak can accommodate three ion sources; however, it is currently equipped with only one prototype ion source. In the 2010 and 2011 KSTAR campaigns, this ion source supplied deuterium neutral beam power of 0.7-1.6 MW to the KSTAR plasma with a beam energy of 70-100 keV. A new ion source will be prepared for the 2012 KSTAR campaign with a much advanced performance compared with the previous one. The newly designed ion source has a very large transparency (∼56%) without deteriorating the beam optics, which is designed to deliver a 2 MW injection power of deuterium beams at 100 keV. The plasma generator of the ion source is of a horizontally cusped bucket type, and the whole inner wall, except the cathode filaments and plasma grid side, functions as an anode. The accelerator assembly consists of four multi-circular aperture grids made of copper and four electrode flanges made of aluminum alloy. The electrodes are insulated using PEEK. The ion source will be completed and tested in 2011.

An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy.

PubMed

Cao, Yun; Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia

2014-02-01

A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C(5+) ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C(5+) ion beam was got when work gas was CH4 while about 262 eμA of C(5+) ion beam was obtained when work gas was C2H2 gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

The negative hydrogen Penning ion gauge ion source for KIRAMS-13 cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

An, D. H.; Jung, I. S.; Kang, J.

2008-02-15

The cold-cathode-type Penning ion gauge (PIG) ion source for the internal ion source of KIRAMS-13 cyclotron has been used for generation of negative hydrogen ions. The dc H-beam current of 650 {mu}A from the PIG ion source with the Dee voltage of 40 kV and arc current of 1.0 A is extrapolated from the measured dc extraction beam currents at the low extraction dc voltages. The output optimization of PIG ion source in the cyclotron has been carried out by using various chimneys with different sizes of the expansion gap between the plasma boundary and the chimney wall. This papermore » presents the results of the dc H-extraction measurement and the expansion gap experiment.« less

The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

NASA Astrophysics Data System (ADS)

Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

2014-02-01

The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

PubMed

Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

2014-02-01

The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

Inner Source Pickup Ions Observed by Ulysses

NASA Astrophysics Data System (ADS)

Gloeckler, G.

2016-12-01

The existence of an inner source of pickup ions close to the Sun was proposed in order to explain the unexpected discovery of C+ in the high-speed polar solar wind. Here I report on detailed analyses of the composition and the radial and latitudinal variations of inner source pickup ions measured with the Solar Wind Ion Composition Spectrometer on Ulysses from 1991 to 1998, approaching and during solar minimum. We find that the C+ intensity drops off with radial distance R as R-1.53, peaks at mid latitudes and drops to its lowest value in the ecliptic. Not only was C+ observed, but also N+, O+, Ne+, Na+, Mg+, Ar+, S+, K+, CH+, NH+, OH+, H2O+, H3O+, MgH+, HCN+, C2H4+, SO+ and many other singly-charged heavy ions and molecular ions. The measured velocity distributions of inner source pickup C+ and O+ indicate that these inner source pickup ions are most likely produced by charge exchange, photoionization and electron impact ionization of neutrals close to the Sun (within 10 to 30 solar radii). Possible causes for the unexpected latitudinal variations and the neutral source(s) producing the inner source pickup ions as well as plausible production mechanisms for inner source pickup ions will be discussed.

Fragmentation study of iridoid glucosides through positive and negative electrospray ionization, collision-induced dissociation and tandem mass spectrometry.

PubMed

Es-Safi, Nour-Eddine; Kerhoas, Lucien; Ducrot, Paul-Henri

2007-01-01

Mass spectrometric methodology based on the combined use of positive and negative electrospray ionization, collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS) has been applied to the mass spectral study of a series of six naturally occurring iridoids through in-source fragmentation of the protonated [M+H]+, deprotonated [M--H]- and sodiated [M+Na]+ ions. This led to the unambiguous determination of the molecular masses of the studied compounds and allowed CID spectra of the molecular ions to be obtained. Valuable structural information regarding the nature of both the glycoside and the aglycone moiety was thus obtained. Glycosidic cleavage and ring cleavages of both aglycone and sugar moieties were the major fragmentation pathways observed during CID, where the losses of small molecules, the cinnamoyl and the cinnamate parts were also observed. The formation of the ionized aglycones, sugars and their product ions was thus obtained giving information on their basic skeleton. The protonated, i.e. [M+H]+ and deprotonated [M--H]-, ions were found to fragment mainly by glycosidic cleavages. MS/MS spectra of the [M+Na]+ ions gave complementary information for the structural characterization of the studied compounds. Unlike the dissociation of protonated molecular ions, that of sodiated molecules also provided sodiated sugar fragments where the C0+ fragment corresponding to the glucose ion was obtained as base peak for all the studied compounds. Copyright (c) 2007 John Wiley & Sons, Ltd.

Extractive electrospray ionization mass spectrometry toward in situ analysis without sample pretreatment.

PubMed

Li, Ming; Hu, Bin; Li, Jianqiang; Chen, Rong; Zhang, Xie; Chen, Huanwen

2009-09-15

A homemade novel nanoextractive electrospray ionization (nanoEESI) source has been characterized for in situ mass spectrometric analysis of ambient samples without sample pretreatment. The primary ions generated using a nanospray emitter interact with the neutral sample plume created by manually nebulizing liquid samples, allowing production of the analyte ions in the spatial cross section of the nanoEESI source. The performance of nanoEESI is experimentally investigated by coupling the nanoEESI source to a commercial LTQ mass spectrometer for rapid analysis of various ambient samples using positive/negative ion detection modes. Compounds of interest in actual samples such as aerosol drug preparations, beverages, milk suspensions, farmland water, and groundwater were unambiguously detected using tandem nanoEESI ion trap mass spectrometry. The limit of detection was low picogram per milliliter levels for the compounds tested. Acceptable relative standard deviation (RSD) values (5-10%) were obtained for direct measurement of analytes in complex matrixes, providing linear dynamic signal responses using manual sample introduction. A single sample analysis was completed within 1.2 s. Requiring no sheath gas for either primary ion production or neutral sample introduction, the nanoEESI has advantages including readiness for miniaturization and integration, simple maintenance, easy operation, and low cost. The experimental data demonstrate that the nanoEESI is a promising tool for high-throughput, sensitive, quantitative, in situ analysis of ambient complex samples, showing potential applications for in situ analysis in multiple disciplines including but not limited to pharmaceutical analysis, food quality control, pesticides residue detection, and homeland security.

Optimization of plasma parameters with magnetic filter field and pressure to maximize H{sup −} ion density in a negative hydrogen ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Won-Hwi; Dang, Jeong-Jeung; Kim, June Young

2016-02-15

Transverse magnetic filter field as well as operating pressure is considered to be an important control knob to enhance negative hydrogen ion production via plasma parameter optimization in volume-produced negative hydrogen ion sources. Stronger filter field to reduce electron temperature sufficiently in the extraction region is favorable, but generally known to be limited by electron density drop near the extraction region. In this study, unexpected electron density increase instead of density drop is observed in front of the extraction region when the applied transverse filter field increases monotonically toward the extraction aperture. Measurements of plasma parameters with a movable Langmuirmore » probe indicate that the increased electron density may be caused by low energy electron accumulation in the filter region decreasing perpendicular diffusion coefficients across the increasing filter field. Negative hydrogen ion populations are estimated from the measured profiles of electron temperatures and densities and confirmed to be consistent with laser photo-detachment measurements of the H{sup −} populations for various filter field strengths and pressures. Enhanced H{sup −} population near the extraction region due to the increased low energy electrons in the filter region may be utilized to increase negative hydrogen beam currents by moving the extraction position accordingly. This new finding can be used to design efficient H{sup −} sources with an optimal filtering system by maximizing high energy electron filtering while keeping low energy electrons available in the extraction region.« less

Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion sourcea)

NASA Astrophysics Data System (ADS)

Kondo, K.; Yamamoto, T.; Sekine, M.; Okamura, M.

2012-02-01

The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (˜100 μA) with high charge (˜10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

Application of ion thruster technology to a 30-cm multipole sputtering ion source

NASA Technical Reports Server (NTRS)

Robinson, R. S.; Kaufman, H. R.

1976-01-01

A 30-cm electron-bombardment ion source has been designed and fabricated for micromachining and sputtering applications. This source has a multipole magnetic field that employs permanent magnets between permeable pole pieces. An average ion current density of 1 ma/sq cm with 500-eV argon ions was selected as a design operating condition. The ion beam at this operating condition was uniform and well collimated, with an average variation of + or -5 percent over the center 20 cm of the beam at a distance up to 30 cm from the ion source.

Simulation of RF power and multi-cusp magnetic field requirement for H- ion sources

NASA Astrophysics Data System (ADS)

Pathak, Manish; Senecha, V. K.; Kumar, Rajnish; Ghodke, Dharmraj. V.

2016-12-01

A computer simulation study for multi-cusp RF based H- ion source has been carried out using energy and particle balance equation for inductively coupled uniformly dense plasma considering sheath formation near the boundary wall of the plasma chamber for RF ion source used as high current injector for 1 Gev H- Linac project for SNS applications. The average reaction rates for different reactions responsible for H- ion production and destruction have been considered in the simulation model. The RF power requirement for the caesium free H- ion source for a maximum possible H- ion beam current has been derived by evaluating the required current and RF voltage fed to the coil antenna using transformer model for Inductively Coupled Plasma (ICP). Different parameters of RF based H- ion source like excited hydrogen molecular density, H- ion density, RF voltage and current of RF antenna have been calculated through simulations in the presence and absence of multicusp magnetic field to distinctly observe the effect of multicusp field. The RF power evaluated for different H- ion current values have been compared with the experimental reported results showing reasonably good agreement considering the fact that some RF power will be reflected from the plasma medium. The results obtained have helped in understanding the optimum field strength and field free regions suitable for volume emission based H- ion sources. The compact RF ion source exhibits nearly 6 times better efficiency compare to large diameter ion source.

Polyatomic ions from a high current ion implanter driven by a liquid metal ion source.

PubMed

Pilz, W; Laufer, P; Tajmar, M; Böttger, R; Bischoff, L

2017-12-01

High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi 2 + ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

Polyatomic ions from a high current ion implanter driven by a liquid metal ion source

NASA Astrophysics Data System (ADS)

Pilz, W.; Laufer, P.; Tajmar, M.; Böttger, R.; Bischoff, L.

2017-12-01

High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi2+ ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

Combined corona discharge and UV photoionization source for ion mobility spectrometry.

PubMed

Bahrami, Hamed; Tabrizchi, Mahmoud

2012-08-15

An ion mobility spectrometer is described which is equipped with two non-radioactive ion sources, namely an atmospheric pressure photoionization and a corona discharge ionization source. The two sources cannot only run individually but are additionally capable of operating simultaneously. For photoionization, a UV lamp was mounted parallel to the axis of the ion mobility cell. The corona discharge electrode was mounted perpendicular to the UV radiation. The total ion current from the photoionization source was verified as a function of lamp current, sample flow rate, and drift field. Simultaneous operation of the two ionization sources was investigated by recording ion mobility spectra of selected samples. The design allows one to observe peaks from either the corona discharge or photoionization individually or simultaneously. This makes it possible to accurately compare peaks in the ion mobility spectra from each individual source. Finally, the instrument's capability for discriminating two peaks appearing in approximately identical drift times using each individual ionization source is demonstrated. Copyright © 2012 Elsevier B.V. All rights reserved.

Production of N[sup +] ions from a multicusp ion beam apparatus

DOEpatents

Kango Leung; Kunkel, W.B.; Walther, S.R.

1993-03-30

A method of generating a high purity (at least 98%) N[sup +] ion beam using a multicusp ion source having a chamber formed by a cylindrical chamber wall surrounded by a plurality of magnets, a filament centrally disposed in said chamber, a plasma electrode having an extraction orifice at one end of the chamber, a magnetic filter having two parallel magnets spaced from said plasma electrode and dividing the chamber into arc discharge and extraction regions. The method includes ionizing nitrogen gas in the arc discharge region of the chamber, maintaining the chamber wall at a positive voltage relative to the filament and at a magnitude for an optimum percentage of N[sup +] ions in the extracted ion beams, disposing a hot liner within the chamber and near the chamber wall to limit recombination of N[sup +] ions into the N[sub 2][sup +] ions, spacing the magnets of the magnetic filter from each other for optimum percentage of N[sup 3] ions in the extracted ion beams, and maintaining a relatively low pressure downstream of the extraction orifice and of a magnitude (preferably within the range of 3-8[times]10[sup [minus]4] torr) for an optimum percentage of N[sup +] ions in the extracted ion beam.

Ion cyclotron resonance cell

DOEpatents

Weller, R.R.

1995-02-14

An ion cyclotron resonance cell is disclosed having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions. 5 figs.

An atmospheric pressure ionization source using a high voltage target compared to electrospray ionization for the LC/MS analysis of pharmaceutical compounds.

PubMed

Lubin, Arnaud; De Vries, Ronald; Cabooter, Deirdre; Augustijns, Patrick; Cuyckens, Filip

2017-08-05

The type and design of an ionization source can have a significant influence on the performances of a bioanalytical method. It is, therefore, of high interest to evaluate the performances of newly introduced sources to highlight their benefits and limitations in comparison to other well established sources. In this paper, liquid chromatography - mass spectrometry (LC/MS) performances of a new atmospheric pressure ionization (API) source, commercialized as UniSpray, is evaluated. The dynamic range of 24 pharmaceutical and biological compounds is compared between the new API source and electrospray ionization (ESI) for 3 different mobile phase conditions. Matrix effects are also compared with ESI on a refined selection of 19 pharmaceutical and biological compounds in 4 matrices commonly encountered in bioanalysis. A slightly better dynamic range towards lower concentrations was often observed with the new API source. Matrix effects were quite similar between the two sources with a small, but statistically significant, lower percentage of matrix effects observed for the new API source in plasma and bile in the positive ion mode, and bile in negative ion mode for ESI. Finally, the sensitivity of late eluting compounds could be improved on the new API source by post-column addition of water. Copyright © 2017 Elsevier B.V. All rights reserved.

Energetic Nitrogen Ions within the Inner Magnetosphere of Saturn

NASA Astrophysics Data System (ADS)

Sittler, E. C.; Johnson, R. E.; Richardson, J. D.; Jurac, S.; Moore, M.; Cooper, J. F.; Mauk, B. H.; Smith, H. T.; Michael, M.; Paranicus, C.; Armstrong, T. P.; Tsurutani, B.; Connerney, J. E. P.

2003-05-01

Titan's interaction with Saturn's magnetosphere will result in the energetic ejection of atomic nitrogen atoms into Saturn's magnetosphere due to dissociation of N2 by electrons, ions, and UV photons. The ejection of N atoms into Saturn's magnetosphere will form a nitrogen torus around Saturn with mean density of about 4 atoms/cm3 with source strength of 4.5x1025 atoms/sec. These nitrogen atoms are ionized by photoionization, electron impact ionization and charge exchange reactions producing an N+ torus of 1-4 keV suprathermal ions centered on Titan's orbital position. We will show Voyager plasma observations that demonstrate presence of a suprathermal ion component within Saturn's outer magnetosphere. The Voyager LECP data also reported the presence of inward diffusing energetic ions from the outer magnetosphere of Saturn, which could have an N+ contribution. If so, when one conserves the first and second adiabatic invariant the N+ ions will have energies in excess of 100 keV at Dione's L shell and greater than 400 keV at Enceladus' L shell. Energetic charged particle radial diffusion coefficients are also used to constrain the model results. But, one must also consider the solar wind as another important source of keV ions, in the form of protons and alpha particles, for Saturn's outer magnetosphere. Initial estimates indicate that a solar wind source could dominate in the outer magnetosphere, but various required parameters for this estimate are highly uncertain and will have to await Cassini results for confirmation. We show that satellite sweeping and charged particle precipitation within the middle and outer magnetosphere will tend to enrich N+ ions relative to protons within Saturn's inner magnetosphere as they diffuse radially inward for radial diffusion coefficients that do not violate observations. Charge exchange reactions within the inner magnetosphere can be an important loss mechanism for O+ ions, but to a lesser degree for N+ ions. Initial LECP results using composition data at energies greater than 200 keV/nucl., showed that heavy ions within Saturn's inner magnetosphere dominated over protons, but that contrary to original suggestions that these ions were O+ , we now argue that they are instead N+ ions. With energetic N+ ions bombarding the icy satellite surfaces chemical reactions can occur at the end of the ion tracks and produce nitrogen oxides or other nitrogen containing molecules such that the radiology within the icy surfaces is driven by the impacting energetic nitrogen ions. These can accumulate over the lifetime of the Saturn system.

New Cs sputter ion source with polyatomic ion beams for secondary ion mass spectrometry applications

NASA Astrophysics Data System (ADS)

Belykh, S. F.; Palitsin, V. V.; Veryovkin, I. V.; Kovarsky, A. P.; Chang, R. J. H.; Adriaens, A.; Dowsett, M. G.; Adams, F.

2007-08-01

A simple design for a cesium sputter ion source compatible with vacuum and ion-optical systems as well as with electronics of the commercially available Cameca IMS-4f instrument is reported. This ion source has been tested with the cluster primary ions of Sin- and Cun-. Our experiments with surface characterization and depth profiling conducted to date demonstrate improvements of the analytical capabilities of the secondary ion mass spectrometry instrument due to the nonadditive enhancement of secondary ion emission and shorter ion ranges of polyatomic projectiles compared to atomic ones with the same impact energy.

An atmospheric pressure chemical ionization study of the positive and negative ion chemistry of the hydrofluorocarbons 1,1-difluoroethane (HFC-152a) and 1,1,1,2-tetrafluoroethane (HFC-134a) and of perfluoro-n-hexane (FC-72) in air plasma at atmospheric pressure.

PubMed

Marotta, Ester; Paradisi, Cristina; Scorrano, Gianfranco

2004-07-01

A report is given on the ionization/dissociation behavior of the title compounds within air plasmas produced by electrical corona discharges at atmospheric pressure: both positive and negative ions were investigated at different temperatures using atmospheric pressure chemical ionization mass spectrometry (APCI-MS). CHF(2)CH(3) (HFC-152a) undergoes efficient ionic oxidation to C(2)H(5)O(+), in which the oxygen comes from water present in the plasma. In contrast, CF(3)CH(2)F (HFC-134a) does not produce any characteristic positive ion under APCI conditions, its presence within the plasma being revealed only as a neutral ligand in ion-molecule complexes with ions of the background (H(3)O(+) and NO(+)). Analogously, the perfluorocarbon FC-72 (n-C(6)F(14)) does not produce significant positive ions at 30 degrees C: at high temperature, however, it undergoes dissociative ionization to form many product ions including C(3)F(6)(+), C(2)F(4)(+), C(n)F(2n+1)(+) and a few families of oxygen containing cations (C(n)F(2n+1)OH(2)(+), C(n)F(2n)OH(+), C(n)F(2n-1)O(+), C(n)F(2n-1)O(2)H(2)(+), C(n)F(2n-2)O(2)H(+)) which are suggested to derive from C(n)F(2n+1)(+) in a cascade of steps initiated by condensation with water followed by steps of HF elimination and H(2)O addition. Negative ions formed from the fluoroethanes CHF(2)CH(3) and CF(3)CH(2)F (M) include complexes with ions of the background, O(2)(-)(M), O(3)(-)(M) and some higher complexes involving also water, and complexes of the fluoride ion, F(-)(H(2)O), F(-)(M) and higher complexes with both M and H(2)O also together. The interesting product O(2)(-)(HF) is also formed from 1,1-difluoroethane. In contrast to the HFCs, perfluoro-n-hexane gives stable molecular anions, M(-), which at low source temperature or in humidified air are also detected as hydrates, M(-)(H(2)O). In addition, in humidified air F(-)(H(2)O)(n) complexes are also formed. The reactions leading to all major positive and negative product ions are discussed also with reference to available thermochemical data and relevant literature reports. The effects on both positive and negative APCI spectra due to ion activation via increasing V(cone) are also reported and discussed: several interesting endothermic processes are observed under these conditions. The results provide important information on the role of ionic reactions in non-thermal plasma processes.

Electron cyclotron resonance ion sources in use for heavy ion cancer therapy.

PubMed

Tinschert, K; Iannucci, R; Lang, R

2008-02-01

The use of electron cyclotron resonance (ECR) ion sources for producing ion beams for heavy ion cancer therapy has been established for more than ten years. After the Heavy Ion Medical Accelerator (HIMAC) at Chiba, Japan started therapy of patients with carbon ions in 1994 the first carbon ion beam for patient treatment at the accelerator facility of GSI was delivered in 1997. ECR ion sources are the perfect tool for providing the required ion beams with good stability, high reliability, and easy maintenance after long operating periods. Various investigations were performed at GSI with different combinations of working gas and auxiliary gas to define the optimal beam conditions for an extended use of further ion species for the dedicated Heidelberg Ion Beam Therapy (HIT) facility installed at the Radiological University Hospital Heidelberg, Germany. Commercially available compact all permanent magnet ECR ion sources operated at 14.5 GHz were chosen for this facility. Besides for (12)C(4+) these ion sources are used to provide beams of (1)H(3)(1+), (3)He(1+), and (16)O(6+). The final commissioning at the HIT facility could be finished at the end of 2006.

Analysis of Sulfate Patterns in Glycosaminoglycan Oligosaccharides by MSn Coupled to Infrared Ion Spectroscopy: the Case of GalNAc4S and GalNAc6S

NASA Astrophysics Data System (ADS)

Renois-Predelus, G.; Schindler, B.; Compagnon, I.

2018-04-01

We report distinctive spectroscopic fingerprints of the monosaccharide standards GalNAc4S and GalNAc6S by coupling mass spectrometry and ion spectroscopy in the 3-μm range. The disaccharide standards CSA and CSC are used to demonstrate the applicability of a novel approach for the analysis of sulfate position in GalNAc-containing glycosaminoglycans. This approach was then used for the analysis of a sample containing CSA and CSC disaccharides. Finally, we discuss the generalization of the coupling of mass spectrometry with ion spectroscopy for the structural analysis of glycosaminoglycans on a tetrasaccharide from dermatan sulfate source. [Figure not available: see fulltext.

PULSED ION SOURCE

DOEpatents

Ford, F.C.; Ruff, J.W.; Zizzo, S.G.; Cook, B.

1958-11-11

An ion source is described adapted for pulsed operation and producing copious quantities of ions with a particular ion egress geometry. The particular source construction comprises a conical member having a conducting surface formed of a metal with a gas occladed therein and narrow non-conducting portions hereon dividing the conducting surface. A high voltage pulse is applied across the conducting surface or producing a discharge across the surface. After the gas ions have been produced by the discharge, the ions are drawn from the source in a diverging conical beam by a specially constructed accelerating electrode.

Simulation study on ion extraction from electron cyclotron resonance ion sources

NASA Astrophysics Data System (ADS)

Fu, S.; Kitagawa, A.; Yamada, S.

1994-04-01

In order to study beam optics of NIRS-ECR ion source used in the HIMAC project, the EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1D and 2D sheath theories are used, respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source are presented in this paper, exhibiting an agreement with the experiment results.

RF synchronized short pulse laser ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuwa, Yasuhiro, E-mail: fuwa@kyticr.kuicr.kyoto-u.ac.jp; Iwashita, Yoshihisa; Tongu, Hiromu

A laser ion source that produces shortly bunched ion beam is proposed. In this ion source, ions are extracted immediately after the generation of laser plasma by an ultra-short pulse laser before its diffusion. The ions can be injected into radio frequency (RF) accelerating bucket of a subsequent accelerator. As a proof-of-principle experiment of the ion source, a RF resonator is prepared and H{sub 2} gas was ionized by a short pulse laser in the RF electric field in the resonator. As a result, bunched ions with 1.2 mA peak current and 5 ns pulse length were observed at themore » exit of RF resonator by a probe.« less

Investigations of the emittance and brightness of ion beams from an electron beam ion source of the Dresden EBIS type.

PubMed

Silze, Alexandra; Ritter, Erik; Zschornack, Günter; Schwan, Andreas; Ullmann, Falk

2010-02-01

We have characterized ion beams extracted from the Dresden EBIS-A, a compact room-temperature electron beam ion source (EBIS) with a permanent magnet system for electron beam compression, using a pepper-pot emittance meter. The EBIS-A is the precursor to the Dresden EBIS-SC in which the permanent magnets have been replaced by superconducting solenoids for the use of the source in high-ion-current applications such as heavy-ion cancer therapy. Beam emittance and brightness values were calculated from data sets acquired for a variety of source parameters, in leaky as well as pulsed ion extraction mode. With box shaped pulses of C(4+) ions at an energy of 39 keV root mean square emittances of 1-4 mm mrad and a brightness of 10 nA mm(-2) mrad(-2) were achieved. The results meet the expectations for high quality ion beams generated by an electron beam ion source.

Bayesian Integration and Classification of Composition C-4 Plastic Explosives Based on Time-of-Flight-Secondary Ion Mass Spectrometry and Laser Ablation-Inductively Coupled Plasma Mass Spectrometry.

PubMed

Mahoney, Christine M; Kelly, Ryan T; Alexander, Liz; Newburn, Matt; Bader, Sydney; Ewing, Robert G; Fahey, Albert J; Atkinson, David A; Beagley, Nathaniel

2016-04-05

Time-of-flight-secondary ion mass spectrometry (TOF-SIMS) and laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) were used for characterization and identification of unique signatures from a series of 18 Composition C-4 plastic explosives. The samples were obtained from various commercial and military sources around the country. Positive and negative ion TOF-SIMS data were acquired directly from the C-4 residue on Si surfaces, where the positive ion mass spectra obtained were consistent with the major composition of organic additives, and the negative ion mass spectra were more consistent with explosive content in the C-4 samples. Each series of mass spectra was subjected to partial least squares-discriminant analysis (PLS-DA), a multivariate statistical analysis approach which serves to first find the areas of maximum variance within different classes of C-4 and subsequently to classify unknown samples based on correlations between the unknown data set and the original data set (often referred to as a training data set). This method was able to successfully classify test samples of C-4, though with a limited degree of certainty. The classification accuracy of the method was further improved by integrating the positive and negative ion data using a Bayesian approach. The TOF-SIMS data was combined with a second analytical method, LA-ICPMS, which was used to analyze elemental signatures in the C-4. The integrated data were able to classify test samples with a high degree of certainty. Results indicate that this Bayesian integrated approach constitutes a robust classification method that should be employable even in dirty samples collected in the field.

Plasma driven neutron/gamma generator

DOEpatents

Leung, Ka-Ngo; Antolak, Arlyn

2015-03-03

An apparatus for the generation of neutron/gamma rays is described including a chamber which defines an ion source, said apparatus including an RF antenna positioned outside of or within the chamber. Positioned within the chamber is a target material. One or more sets of confining magnets are also provided to create a cross B magnetic field directly above the target. To generate neutrons/gamma rays, the appropriate source gas is first introduced into the chamber, the RF antenna energized and a plasma formed. A series of high voltage pulses are then applied to the target. A plasma sheath, which serves as an accelerating gap, is formed upon application of the high voltage pulse to the target. Depending upon the selected combination of source gas and target material, either neutrons or gamma rays are generated, which may be used for cargo inspection, and the like.

Compact 2.45 GHz ECR Ion Source for generation of singly-charged ions

NASA Astrophysics Data System (ADS)

Fatkullin, Riyaz; Bogomolov, Sergey; Kuzmenkov, Konstantin; Efremov, Andrey

2018-04-01

2.45 GHz ECR ion sources are widely used for production of protons, single charged heavy ions and secondary radioactive ion beams. This paper describes the development of a compact ECR ion source based on 2.45 GHz coaxial resonator. The first results of extracted current measurements at different resonator configuration as a function of UHF frequency, power and gas flow are presented.

Tandem-Mirror Ion Source

NASA Technical Reports Server (NTRS)

Biddle, A.; Stone, N.; Reasoner, D.; Chisholm, W.; Reynolds, J.

1986-01-01

Improved ion source produces beam of ions at any kinetic energy from 1 to 1,000 eV, with little spread in energy or angle. Such ion beams useful in studies of surface properties of materials, surface etching, deposition, and development of plasma-diagnostic instrumentation. Tandemmirror ion source uses electrostatic and magnetic fields to keep electrons in ionization chamber and assure uniform output ion beam having low divergence in energy and angle.

System integration of RF based negative ion experimental facility at IPR

NASA Astrophysics Data System (ADS)

Bansal, G.; Bandyopadhyay, M.; Singh, M. J.; Gahlaut, A.; Soni, J.; Pandya, K.; Parmar, K. G.; Sonara, J.; Chakraborty, A.

2010-02-01

The setting up of RF based negative ion experimental facility shall witness the beginning of experiments on the negative ion source fusion applications in India. A 1 MHz RF generator shall launch 100 kW RF power into a single driver on the plasma source to produce a plasma of density ~5 × 1012 cm-3. The source can deliver a negative ion beam of ~10 A with a current density of ~30 mA/cm2 and accelerated to 35 kV through an electrostatic ion accelerator. The experimental system is similar to a RF based negative ion source, BATMAN, presently operating at IPP. The subsystems for source operation are designed and procured principally from indigenous resources, keeping the IPP configuration as a base line. The operation of negative ion source is supported by many subsystems e.g. vacuum pumping system with gate valves, cooling water system, gas feed system, cesium delivery system, RF generator, high voltage power supplies, data acquisition and control system, and different diagnostics. The first experiments of negative ion source are expected to start at IPR from the middle of 2009.

Laser-ablation-based ion source characterization and manipulation for laser-driven ion acceleration

NASA Astrophysics Data System (ADS)

Sommer, P.; Metzkes-Ng, J.; Brack, F.-E.; Cowan, T. E.; Kraft, S. D.; Obst, L.; Rehwald, M.; Schlenvoigt, H.-P.; Schramm, U.; Zeil, K.

2018-05-01

For laser-driven ion acceleration from thin foils (∼10 μm–100 nm) in the target normal sheath acceleration regime, the hydro-carbon contaminant layer at the target surface generally serves as the ion source and hence determines the accelerated ion species, i.e. mainly protons, carbon and oxygen ions. The specific characteristics of the source layer—thickness and relevant lateral extent—as well as its manipulation have both been investigated since the first experiments on laser-driven ion acceleration using a variety of techniques from direct source imaging to knife-edge or mesh imaging. In this publication, we present an experimental study in which laser ablation in two fluence regimes (low: F ∼ 0.6 J cm‑2, high: F ∼ 4 J cm‑2) was applied to characterize and manipulate the hydro-carbon source layer. The high-fluence ablation in combination with a timed laser pulse for particle acceleration allowed for an estimation of the relevant source layer thickness for proton acceleration. Moreover, from these data and independently from the low-fluence regime, the lateral extent of the ion source layer became accessible.

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, W.; Zhao, H.W.; Liu, Zh.W.

To study the injection of additional electrons from an external electron gun into the plasma of a Penning ionization gauge (PIG) ion source, a test bench for the external electron-beam enhancement of the PIG (E-PIG) ion source was set up. A source magnet assembly was built to satisfy the request for magnetic field configuration of the E-PIG ion source. Numerical calculations have been done to optimize the magnetic field configuration so as to fit the primary electrons to be fed into the PIG discharge chamber along the spreading magnetic field lines. Many possible methods for improving the performance and stabilitymore » of the PIG ion source have been used in the E-PIG ion source, including the use of multicrystal LaB{sub 6} cathode and optimized axial magnetic field. This article presents a detailed design of the E-PIG ion source. Substantial enhancement of ion charge state is expected to be observed which demonstrates that the E-PIG is a viable alternative to other much more costly and difficult to operate devices for the production of intense ion beams of higher charge state.« less

Formation of Metal-Adducted Analyte Ions by Flame-Induced Atmospheric Pressure Chemical Ionization Mass Spectrometry.

PubMed

Cheng, Sy-Chyi; Wang, Chin-Hsiung; Shiea, Jentaie

2016-05-17

A flame-induced atmospheric pressure chemical ionization (FAPCI) source, consisting of a miniflame, nebulizer, and heated tube, was developed to ionize analytes. The ionization was performed by reacting analytes with a charged species generated in a flame. A stainless steel needle deposited with saturated alkali chloride solution was introduced into the mini oxyacetylene flame to generate alkali ions, which were reacted with analytes (M) generated in a heated nebulizer. The alkali-adducted 18-crown-6 ether ions, including (M + Li)(+), (M + Na)(+), (M + K)(+), (M + Rb)(+), and (M + Cs)(+), were successfully detected on the FAPCI mass spectra when the corresponding alkali chloride solutions were separately introduced to the flame. When an alkali chloride mixture was introduced, all alkali-adducted analyte ions were simultaneously detected. Their intensity order was as follows: (M + Cs)(+) > (M + Rb)(+) > (M + K)(+) > (M + Na)(+) > (M + Li)(+), and this trend agreed with the lattice energies of alkali chlorides. Besides alkali ions, other transition metal ions such as Ni(+), Cu(+), and Ag(+) were generated in a flame for analyte ionization. Other than metal ions, the reactive species generated in the fossil fuel flame could also be used to ionize analytes, which formed protonated analyte ions (M + H)(+) in positive ion mode and deprotonated analyte ions (M - H)(-) in negative ion mode.

Review on heavy ion radiotherapy facilities and related ion sources (invited)a)

NASA Astrophysics Data System (ADS)

Kitagawa, A.; Fujita, T.; Muramatsu, M.; Biri, S.; Drentje, A. G.

2010-02-01

Heavy ion radiotherapy awakens worldwide interest recently. The clinical results obtained by the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan have clearly demonstrated the advantages of carbon ion radiotherapy. Presently, there are four facilities for heavy ion radiotherapy in operation, and several new facilities are under construction or being planned. The most common requests for ion sources are a long lifetime and good stability and reproducibility. Sufficient intensity has been achieved by electron cyclotron resonance ion sources at the present facilities.

Development of Compact Electron Cyclotron Resonance Ion Source with Permanent Magnets for High-Energy Carbon-Ion Therapy

NASA Astrophysics Data System (ADS)

Muramatsu, M.; Kitagawa, A.; Iwata, Y.; Hojo, S.; Sakamoto, Y.; Sato, S.; Ogawa, Hirotsugu; Yamada, S.; Ogawa, Hiroyuki; Yoshida, Y.; Ueda, T.; Miyazaki, H.; Drentje, A. G.

2008-11-01

Heavy-ion cancer treatment is being carried out at the Heavy Ion Medical Accelerator in Chiba (HIMAC) with 140 to 400 MeV/n carbon ions at National Institute of Radiological Sciences (NIRS) since 1994. At NIRS, more than 4,000 patients have been treated, and the clinical efficiency of carbon ion radiotherapy has been demonstrated for many diseases. A more compact accelerator facility for cancer therapy is now being constricted at the Gunma University. In order to reduce the size of the injector (consists of ion source, low-energy beam transport and post-accelerator Linac include these power supply and cooling system), an ion source requires production of highly charged carbon ions, lower electric power for easy installation of the source on a high-voltage platform, long lifetime and easy operation. A compact Electron Cyclotron Resonance Ion Source (ECRIS) with all permanent magnets is one of the best types for this purpose. An ECRIS has advantage for production of highly charged ions. A permanent magnet is suitable for reduce the electric power and cooling system. For this, a 10 GHz compact ECRIS with all permanent magnets (Kei2-source) was developed. The maximum mirror magnetic fields on the beam axis are 0.59 T at the extraction side and 0.87 T at the gas-injection side, while the minimum B strength is 0.25 T. These parameters have been optimized for the production of C4+ based on experience at the 10 GHz NIRS-ECR ion source. The Kei2-source has a diameter of 320 mm and a length of 295 mm. The beam intensity of C4+ was obtained to be 618 eμA under an extraction voltage of 30 kV. Outline of the heavy ion therapy and development of the compact ion source for new facility are described in this paper.

RCNP Project on Polarized {sup 3}He Ion Sources - From Optical Pumping to Cryogenic Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, M.; Inomata, T.; Takahashi, Y.

2009-08-04

A polarized {sup 3}He ion source has been developed at RCNP for intermediate and high energy spin physics. Though we started with an OPPIS (Optical Pumping Polarized Ion Source), it could not provide highly polarized {sup 3}He beam because of fundamental difficulties. Subsequently to this unhappy result, we examined novel types of the polarized {sup 3}He ion source, i.e., EPPIS (Electron Pumping Polarized Ion Source), and ECRPIS (ECR Polarized Ion Source) experimentally or theoretically, respectively. However, attainable {sup 3}He polarization degrees and beam intensities were still insufficient for practical use. A few years later, we proposed a new idea formore » the polarized {sup 3}He ion source, SEPIS (Spin Exchange Polarized Ion Source) which is based on enhanced spin-exchange cross sections at low incident energies for {sup 3}He{sup +}+Rb, and its feasibility was experimentally examined.Recently, we started a project on polarized {sup 3}He gas generated by the brute force method with low temperature (approx4 mK) and strong magnetic field (approx17 T), and rapid melting of highly polarized solid {sup 3}He followed by gasification. When this project will be successful, highly polarized {sup 3}He gas will hopefully be used for a new type of the polarized {sup 3}He ion source.« less

Characterization of charge separation in the Array of Micromachined UltraSonic Electrospray (AMUSE) ion source for mass spectrometry.

PubMed

Forbes, Thomas P; Dixon, R Brent; Muddiman, David C; Degertekin, F Levent; Fedorov, Andrei G

2009-09-01

An initial investigation into the effects of charge separation in the Array of Micromachined UltraSonic Electrospray (AMUSE) ion source is reported to gain understanding of ionization mechanisms and to improve analyte ionization efficiency and operation stability. In RF-only mode, AMUSE ejects, on average, an equal number of slightly positive and slightly negative charged droplets due to random charge fluctuations, providing inefficient analyte ionization. Charge separation at the nozzle orifice is achieved by the application of an external electric field. By bringing the counter electrode close to the nozzle array, strong electric fields can be applied at relatively low DC potentials. It has been demonstrated, through a number of electrode/electrical potential configurations, that increasing charge separation leads to improvement in signal abundance, signal-to-noise ratio, and signal stability.

Emittance studies of the 2.45 GHz permanent magnet ECR ion source

NASA Astrophysics Data System (ADS)

Zelenak, A.; Bogomolov, S. L.; Yazvitsky, N. Yu.

2004-05-01

During the past several years different types of permanent magnet 2.45 GHz (electron cyclotron resonance) ion sources were developed for production of singly charged ions. Ion sources of this type are used in the first stage of DRIBs project, and are planned to be used in the MASHA mass separator. The emittance of the beam provided by the source is one of the important parameters for these applications. An emittance scanner composed from a set of parallel slits and rotary wire beam profile monitor was used for the studying of the beam emittance characteristics. The emittance of helium and argon ion beams was measured with different shapes of the plasma electrode for several ion source parameters: microwave power, source potential, plasma aperture-puller aperture gap distance, gas pressure. The results of measurements are compared with previous simulations of ion optics.

Ion source and injection line for high intensity medical cyclotron

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, XianLu, E-mail: jiaxl@ciae.ac.cn; Guan, Fengping; Yao, Hongjuan

2014-02-15

A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H− ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H− ion source (CIAE-CH-I type) and a short injection line, which the H− ion source of 3 mA/25 keV H− beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from themore » extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.« less

A tandem-based compact dual-energy gamma generator.

PubMed

Persaud, A; Kwan, J W; Leitner, M; Leung, K-N; Ludewigt, B; Tanaka, N; Waldron, W; Wilde, S; Antolak, A J; Morse, D H; Raber, T

2010-02-01

A dual-energy tandem-type gamma generator has been developed at E. O. Lawrence Berkeley National Laboratory and Sandia National Laboratories. The tandem accelerator geometry allows higher energy nuclear reactions to be reached, thereby allowing more flexible generation of MeV-energy gammas for active interrogation applications. Both positively charged ions and atoms of hydrogen are created from negative ions via a gas stripper. In this paper, we show first results of the working tandem-based gamma generator and that a gas stripper can be utilized in a compact source design. Preliminary results of monoenergetic gamma production are shown.

Behavior of the Chinchs of Shield Bug under the Effect of Pheromones,

DTIC Science & Technology

1977-06-14

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Visualization of air and metal inhomogeneities in phantoms irradiated by carbon ion beams using prompt secondary ions.

PubMed

Gaa, T; Reinhart, M; Hartmann, B; Jakubek, J; Soukup, P; Jäkel, O; Martišíková, M

2017-06-01

Non-invasive methods for monitoring of the therapeutic ion beam extension in the patient are desired in order to handle deteriorations of the dose distribution related to changes of the patient geometry. In carbon ion radiotherapy, secondary light ions represent one of potential sources of information about the dose distribution in the irradiated target. The capability to detect range-changing inhomogeneities inside of an otherwise homogeneous phantom, based on single track measurements, is addressed in this paper. Air and stainless steel inhomogeneities, with PMMA equivalent thickness of 10mm and 4.8mm respectively, were inserted into a PMMA-phantom at different positions in depth. Irradiations of the phantom with therapeutic carbon ion pencil beams were performed at the Heidelberg Ion Beam Therapy Center. Tracks of single secondary ions escaping the phantom under irradiation were detected with a pixelized semiconductor detector Timepix. The statistical relevance of the found differences between the track distributions with and without inhomogeneities was evaluated. Measured shifts of the distal edge and changes in the fragmentation probability make the presence of inhomogeneities inserted into the traversed medium detectable for both, 10mm air cavities and 1mm thick stainless steel. Moreover, the method was shown to be sensitive also on their position in the observed body, even when localized behind the Bragg-peak. The presented results demonstrate experimentally, that the method using distributions of single secondary ion tracks is sensitive to the changes of homogeneity of the traversed material for the studied geometries of the target. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Yun, E-mail: caoyun@impcas.ac.cn; Li, Jia Qing; Sun, Liang Ting

2014-02-15

A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C{sup 5+} ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C{sup 5+} ion beam was got when work gasmore » was CH{sub 4} while about 262 eμA of C{sup 5+} ion beam was obtained when work gas was C{sub 2}H{sub 2} gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.« less

Structural micro-porous carbon anode for rechargeable lithium-ion batteries

DOEpatents

Delnick, Frank M.; Even, Jr., William R.; Sylwester, Alan P.; Wang, James C. F.; Zifer, Thomas

1995-01-01

A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc.

Compact RF ion source for industrial electrostatic ion accelerator

NASA Astrophysics Data System (ADS)

Kwon, Hyeok-Jung; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub

2016-02-01

Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

Compact RF ion source for industrial electrostatic ion accelerator.

PubMed

Kwon, Hyeok-Jung; Park, Sae-Hoon; Kim, Dae-Il; Cho, Yong-Sub

2016-02-01

Korea Multi-purpose Accelerator Complex is developing a single-ended electrostatic ion accelerator to irradiate gaseous ions, such as hydrogen and nitrogen, on materials for industrial applications. ELV type high voltage power supply has been selected. Because of the limited space, electrical power, and robust operation, a 200 MHz RF ion source has been developed. In this paper, the accelerator system, test stand of the ion source, and its test results are described.

A vacuum spark ion source: High charge state metal ion beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yushkov, G. Yu., E-mail: gyushkov@mail.ru; Nikolaev, A. G.; Frolova, V. P.

2016-02-15

High ion charge state is often important in ion beam physics, among other reasons for the very practical purpose that it leads to proportionately higher ion beam energy for fixed accelerating voltage. The ion charge state of metal ion beams can be increased by replacing a vacuum arc ion source by a vacuum spark ion source. Since the voltage between anode and cathode remains high in a spark discharge compared to the vacuum arc, higher metal ion charge states are generated which can then be extracted as an ion beam. The use of a spark of pulse duration less thanmore » 10 μs and with current up to 10 kA allows the production of ion beams with current of several amperes at a pulse repetition rate of up to 5 pps. We have demonstrated the formation of high charge state heavy ions (bismuth) of up to 15 + and a mean ion charge state of more than 10 +. The physics and techniques of our vacuum spark ion source are described.« less

The modification at CSNS ion source

NASA Astrophysics Data System (ADS)

Liu, S.; Ouyang, H.; Huang, T.; Xiao, Y.; Cao, X.; Lv, Y.; Xue, K.; Chen, W.

2017-08-01

The commissioning of CSNS front end has been finished. Above 15 mA beam intensity is obtained at the end of RFQ. For CSNS ion source, it is a type of penning surface plasma ion source, similar to ISIS ion source. To improve the operation stability and reduce spark rate, some modifications have been performed, including Penning field, extraction optics and post acceleration. PBGUNS is applied to optimize beam extraction. The co-extraction electrons are considered at PBGUNS simulation and various extracted structure are simulated aiming to make the beam through the extracted electrode without loss. The stability of ion source is improved further.

Electron beam ion source and electron beam ion trap (invited).

PubMed

Becker, Reinard; Kester, Oliver

2010-02-01

The electron beam ion source (EBIS) and its trap variant [electron beam ion trap (EBIT)] celebrated their 40th and 20th anniversary, respectively, at the EBIS/T Symposium 2007 in Heidelberg. These technologically challenging sources of highly charged ions have seen a broad development in many countries over the last decades. In contrast to most other ion sources the recipe of improvement was not "sorcery" but a clear understanding of the physical laws and obeying the technological constraints. This review will report important achievements of the past as well as promising developments in the future.

The ionization length in plasmas with finite temperature ion sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jelic, N.; Kos, L.; Duhovnik, J.

2009-12-15

The ionization length is an important quantity which up to now has been precisely determined only in plasmas which assume that the ions are born at rest, i.e., in discharges known as 'cold ion-source' plasmas. Presented here are the results of our calculations of the ionization lengths in plasmas with an arbitrary ion source temperature. Harrison and Thompson (H and T) [Proc. Phys. Soc. 74, 145 (1959)] found the values of this quantity for the cases of several ion strength potential profiles in the well-known Tonks-Langmuir [Phys. Rev. 34, 876 (1929)] discharge, which is characterized by 'cold' ion temperature. Thismore » scenario is also known as the 'singular' ion-source discharge. The H and T analytic result covers cases of ion sources proportional to exp(betaPHI) with PHI the normalized plasma potential and beta=0,1,2 values, which correspond to particular physical scenarios. Many years following H and T's work, Bissell and Johnson (B and J) [Phys. Fluids 30, 779 (1987)] developed a model with the so-called 'warm' ion-source temperature, i.e., 'regular' ion source, under B and J's particular assumption that the ionization strength is proportional to the local electron density. However, it appears that B and J were not interested in determining the ionization length at all. The importance of this quantity to theoretical modeling was recognized by Riemann, who recently answered all the questions of the most advanced up-to-date plasma-sheath boundary theory with cold ions [K.-U. Riemann, Phys. Plasmas 13, 063508 (2006)] but still without the stiff warm ion-source case solution, which is highly resistant to solution via any available analytic method. The present article is an extension of H and T's results obtained for a single point only with ion source temperature T{sub n}=0 to arbitrary finite ion source temperatures. The approach applied in this work is based on the method recently developed by Kos et al. [Phys. Plasmas 16, 093503 (2009)].« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Shu-Xia; Zhang, Yu-Ru; Research Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp

A hybrid model is used to investigate the fragmentation of C{sub 4}F{sub 8} inductive discharges. Indeed, the resulting reactive species are crucial for the optimization of the Si-based etching process, since they determine the mechanisms of fluorination, polymerization, and sputtering. In this paper, we present the dissociation degree, the density ratio of F vs. C{sub x}F{sub y} (i.e., fluorocarbon (fc) neutrals), the neutral vs. positive ion density ratio, details on the neutral and ion components, and fractions of various fc neutrals (or ions) in the total fc neutral (or ion) density in a C{sub 4}F{sub 8} inductively coupled plasma source,more » as well as the effect of pressure and power on these results. To analyze the fragmentation behavior, the electron density and temperature and electron energy probability function (EEPF) are investigated. Moreover, the main electron-impact generation sources for all considered neutrals and ions are determined from the complicated C{sub 4}F{sub 8} reaction set used in the model. The C{sub 4}F{sub 8} plasma fragmentation is explained, taking into account many factors, such as the EEPF characteristics, the dominance of primary and secondary processes, and the thresholds of dissociation and ionization. The simulation results are compared with experiments from literature, and reasonable agreement is obtained. Some discrepancies are observed, which can probably be attributed to the simplified polymer surface kinetics assumed in the model.« less

Bulk plasma fragmentation in a C4F8 inductively coupled plasma: A hybrid modeling study

NASA Astrophysics Data System (ADS)

Zhao, Shu-Xia; Zhang, Yu-Ru; Gao, Fei; Wang, You-Nian; Bogaerts, Annemie

2015-06-01

A hybrid model is used to investigate the fragmentation of C4F8 inductive discharges. Indeed, the resulting reactive species are crucial for the optimization of the Si-based etching process, since they determine the mechanisms of fluorination, polymerization, and sputtering. In this paper, we present the dissociation degree, the density ratio of F vs. CxFy (i.e., fluorocarbon (fc) neutrals), the neutral vs. positive ion density ratio, details on the neutral and ion components, and fractions of various fc neutrals (or ions) in the total fc neutral (or ion) density in a C4F8 inductively coupled plasma source, as well as the effect of pressure and power on these results. To analyze the fragmentation behavior, the electron density and temperature and electron energy probability function (EEPF) are investigated. Moreover, the main electron-impact generation sources for all considered neutrals and ions are determined from the complicated C4F8 reaction set used in the model. The C4F8 plasma fragmentation is explained, taking into account many factors, such as the EEPF characteristics, the dominance of primary and secondary processes, and the thresholds of dissociation and ionization. The simulation results are compared with experiments from literature, and reasonable agreement is obtained. Some discrepancies are observed, which can probably be attributed to the simplified polymer surface kinetics assumed in the model.

Efficiency of Cs-free materials for negative ion production in H2 and D2 plasmas

NASA Astrophysics Data System (ADS)

Friedl, R.; Kurutz, U.; Fantz, U.

2017-08-01

High power negative ion sources use caesium to reduce the work function of the converter surface which significantly increases the negative ion yield. Caesium, however, is a very reactive alkali-metal and shows complex redistribution dynamics in consequence of plasma-surface-interaction. Thus, maintaining a stable and homogenous low work function surface is a demanding task, which is not easily compatible with the RAMI issues (reliability, availability, maintainability, inspectability) for a future DEMO fusion reactor. Hence, Cs-free alternative materials for efficient negative ion formation are desirable. At the laboratory experiment HOMER materials which are referred to as promising are investigated under identical and ion source relevant parameters: the refractory metals Ta and W, non-doped and boron-doped diamond as well as materials with inherent low work function (lanthanum-doped molybdenum, MoLa and lanthanum hexaboride, LaB6). The results are compared to the effect of in-situ caesiation, which at HOMER leads to a maximal increase of the negative ion density by a factor of 2.5. Among the examined samples low work function materials are most efficient. In particular, MoLa leads to an increase of almost 50 % compared to pure volume formation. The difference to a caesiated surface can be attributed to the still higher work function of MoLa, which is expected to be slightly below 3 eV. Using deuterium instead of hydrogen leads to increased atomic and positive ion densities, while comparable negative ion densities are achieved. In contrast to the low work function materials, bulk samples of the refractory metals as well as carbon based materials have no enhancing effect on H-, where the latter materials furthermore show severe erosion due to the hydrogen plasma.

Inductively generated streaming plasma ion source

DOEpatents

Glidden, Steven C.; Sanders, Howard D.; Greenly, John B.

2006-07-25

A novel pulsed, neutralized ion beam source is provided. The source uses pulsed inductive breakdown of neutral gas, and magnetic acceleration and control of the resulting plasma, to form a beam. The beam supplies ions for applications requiring excellent control of ion species, low remittance, high current density, and spatial uniformity.

Ion Sources

NASA Astrophysics Data System (ADS)

Haseroth, Helmut; Hora, Heinrich

1993-03-01

Ion sources for accelerators are based on plasma configurations with an extraction system in order to gain a very high number of ions within an appropriately short pulse and of sufficiently high charge number Z for advanced research. Beginning with the duoplasmatron, all established ion sources are based on low-density plasmas, of which the electron beam ionization source (EBIS) and the electron cyclotron resonance (ECR) source are the most advanced; for example they result in pulses of nearly 6 × 108 fully stripped sulfur ions per pulse in the Super Proton Synchrotron (SPS) at CERN with energies of 200 GeV/u. As an example of a forthcoming development, we are reporting about the lead ion source for the same purpose. Contrary to these cases of low-density plasmas, where a rather long time is always necessary to generate sufficiently high charge states, the laser ion source uses very high density plasmas and therefore produced, for example in 1983, single shots of Au51+ ions of high directivity with energies above 300 MeV within 2 ns irradiation time of a gold target with a medium-to-large CO2 laser. Experiments at Dubna and Moscow, using small-size lasers, produced up to one million shots with 1 Hz sequence. After acceleration by a linac or otherwise, ion pulses of up to nearly 5 × 1010 ions of C4+ or Mg12+ with energies in the synchrotrons of up to 2 GeV/u were produced. The physics of the laser generation of the ions is most complex, as we know from laser fusion studies, including non-linear dynamic and dielectric effects, resonances, self-focusing, instabilities, double layers, and an irregular pulsation in the 20 ps range. This explains not only what difficulties are implied with the laser ion source, but also why it opens up a new direction of ion sources.

Use of predissociation to enhance the atomic hydrogen ion fraction in ion sources

DOEpatents

Kim, Jinchoon

1979-01-01

A duopigatron ion source is modified by replacing the normal oxide-coated wire filament cathode of the ion source with a hot tungsten oven through which hydrogen gas is fed into the arc chamber. The hydrogen gas is predissociated in the hot oven prior to the arc discharge, and the recombination rate is minimized by hot walls inside of the arc chamber. With the use of the above modifications, the atomic H.sub.1.sup.+ ion fraction output can be increased from the normal 50% to greater than 70% with a corresponding decrease in the H.sub.2.sup.+ and H.sub.3.sup.+ molecular ion fraction outputs from the ion source.

Simultaneous screening for 238 drugs in blood by liquid chromatography-ion spray tandem mass spectrometry with multiple-reaction monitoring.

PubMed

Gergov, M; Ojanperä, I; Vuori, E

2003-09-25

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the qualitative screening for 238 drugs in blood samples, which is considerably more than in previous methods. After a two-step liquid-liquid extraction and C(18) chromatography, the compounds were introduced into a triple quadrupole mass spectrometer equipped with a turbo ion spray ion source operating in the positive ionization mode. Identification was based on the compound's absolute retention time, protonated molecular ion, and one representative fragment ion obtained by multiple reaction monitoring (MRM) at an individually selected collision energy of 20, 35, or 50 eV. The limit of detection (LOD) for the majority of the compounds (80%) was < or = 0.05 mg/l, ranging from 0.002 mg/l (e.g., antihistamines) to 5 mg/l (acidic compounds), and for malathion it was 10 mg/l. The LOD values were sufficiently low to allow the majority of compounds to be detected at therapeutic concentrations in the blood.

A radio source occultation experiment with comet Austin 1982g, with unusual results

NASA Technical Reports Server (NTRS)

De Pater, I.; Ip, W.-H.

1984-01-01

A radio source occultation by comet Austin 1982g was observed on September 15-16, 1982. A change in the apparent position of 1242 + 41 by 1.3 arcsec occurred when the source was 220,000 km away from the cometary ion tail. If this change was due to refraction by the cometary plasma, it indicates an electron density of the plasma of about 10,000/cu cm. When the radio source was on the other side of the plasma tail, at a distance of 230,000 km, the position angle of the electric vector of the radio source changed gradually over about 140 deg within two hours. This observation cannot be explained in terms of ionospheric Faraday rotation, and results from either an intrinsic change in the radio source or Faraday rotation in the cometary plasma due to a change in the direction and/or strength of the magnetic field. In the latter case, the cometary coma must have an electron density and a magnetic field strength orders of magnitude larger than current theories predict.

Simultaneous determination of asperosaponin VI and its active metabolite hederagenin in rat plasma by liquid chromatography-tandem mass spectrometry with positive/negative ion-switching electrospray ionization and its application in pharmacokinetic study.

PubMed

Zhu, He; Ding, Li; Shakya, Shailendra; Qi, Xiemin; Hu, Linlin; Yang, Xiaolin; Yang, Zhonglin

2011-11-15

A new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method operated in the positive/negative electrospray ionization (ESI) switching mode has been developed and validated for the simultaneous determination of asperosaponin VI and its active metabolite hederagenin in rat plasma. After addition of internal standards diazepam (for asperosaponin VI) and glycyrrhetic acid (for hederagenin), the plasma sample was deproteinized with acetonitrile, and separated on a reversed phase C18 column with a mobile phase of methanol (solvent A)-0.05% glacial acetic acid containing 10 mM ammonium acetate and 30 μM sodium acetate (solvent B) using gradient elution. The detection of target compounds was done in multiple reaction monitoring (MRM) mode using a tandem mass spectrometry equipped with positive/negative ion-switching ESI source. At the first segment, the MRM detection was operated in the positive ESI mode using the transitions of m/z 951.5 ([M+Na](+))→347.1 for asperosaponin VI and m/z 285.1 ([M+H](+))→193.1 for diazepam for 4 min, then switched to the negative ESI mode using the transitions of m/z 471.3 ([M-H](-))→471.3 for hederagenin and m/z 469.4 ([M-H](-))→425.4 for glycyrrhetic acid, respectively. The sodiated molecular ion [M+Na](+) at m/z 951.5 was selected as the precursor ion for asperosaponin VI, since it provided better sensitivity compared to the deprotonated and protonated molecular ions. Sodium acetate was added to the mobile phase to make sure that abundant amount of the sodiated molecular ion of asperosaponin VI could be produced, and more stable and intensive mass response of the product ion could be obtained. For the detection of hederagenin, since all of the mass responses of the fragment ions were very weak, the deprotonated molecular ion [M-H](-)m/z 471.3 was employed as both the precursor ion and the product ion. But the collision energy was still used for the MRM, in order to eliminate the influences induced by the interference substances from the rat plasma. The validated method was successfully applied to study the pharmacokinetics of asperosaponin VI and its active metabolite hederagenin in rat plasma after oral administration of asperosaponin VI at a dose of 90 mg/kg. Copyright © 2011 Elsevier B.V. All rights reserved.

Means for obtaining a metal ion beam from a heavy-ion cyclotron source

DOEpatents

Hudson, E.D.; Mallory, M.L.

1975-08-01

A description is given of a modification to a cyclotron ion source used in producing a high intensity metal ion beam. A small amount of an inert support gas maintains the usual plasma arc, except that it is necessary for the support gas to have a heavy mass, e.g., xenon or krypton as opposed to neon. A plate, fabricated from the metal (or anything that can be sputtered) to be ionized, is mounted on the back wall of the ion source arc chamber and is bombarded by returning energetic low-charged gas ions that fail to cross the initial accelerating gap between the ion source and the accelerating electrode. Some of the atoms that are dislodged from the plate by the returning gas ions become ionized and are extracted as a useful beam of heavy ions. (auth)

Study of negative ion transport phenomena in a plasma source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riz, D.; Pamela, J.

1996-07-01

NIETZSCHE (Negative Ions Extraction and Transport ZSimulation Code for HydrogEn species) is a negative ion (NI) transport code developed at Cadarache. This code calculates NI trajectories using a 3D Monte-Carlo technique, taking into account the main destruction processes, as well as elastic collisions (H{sup {minus}}/H{sup +}) and charge exchanges (H{sup {minus}}/H{sup 0}). It determines the extraction probability of a NI created at a given position. According to the simulations, we have seen that in the case of volume production, only NI produced close to the plasma grid (PG) can be extracted. Concerning the surface production, we have studied how NImore » produced on the PG and accelerated by the plasma sheath backward into the source could be extracted. We demonstrate that elastic collisions and charge exchanges play an important role, which in some conditions dominates the magnetic filter effect, which acts as a magnetic mirror. NI transport in various conditions will be discussed: volume/surface production, high/low plasmas density, tent filter/transverse filter. {copyright} {ital 1996 American Institute of Physics.}« less

Implementation of Design Changes Towards a More Reliable, Hands-off Magnetron Ion Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sosa, A.; Bollinger, D. S.; Karns, P. R.

As the main H- ion source for the accelerator complex, magnetron ion sources have been used at Fermilab since the 1970’s. At the offline test stand, new R&D is carried out to develop and upgrade the present magnetron-type sources of H- ions of up to 80 mA and 35 keV beam energy in the context of the Proton Improvement Plan. The aim of this plan is to provide high-power proton beams for the experiments at FNAL. In order to reduce the amount of tuning and monitoring of these ion sources, a new electronic system consisting of a current-regulated arc dischargemore » modulator allow the ion source to run at a constant arc current for improved beam output and operation. A solenoid-type gas valve feeds H2 gas into the source precisely and independently of ambient temperature. This summary will cover several studies and design changes that have been tested and will eventually be implemented on the operational magnetron sources at Fermilab. Innovative results for this type of ion source include cathode geometries, solenoid gas valves, current controlled arc pulser, cesium boiler redesign, gas mixtures of hydrogen and nitrogen, and duty factor reduction, with the aim to improve source lifetime, stability, and reducing the amount of tuning needed. In this summary, I will highlight the advances made in ion sources at Fermilab and will outline the directions of the continuing R&D effort.« less

Electrochemical activity of Fe-MIL-100 as a positive electrode for Na-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sava Gallis, Dorina F.; Pratt III, Harry D.; Anderson, Travis M.

2016-01-01

Here we investigate the electrochemical activity of metal-organic frameworks (MOFs) as positive electrodes for Na-ion batteries in coin cell configurations. The performance of Fe-MIL-100 material is highly dependent on the choice of sodium salt source, and electrolyte system. The overall capacity fades over many cycles, however the high Coulombic efficiency is maintained. This can be correlated with inaccessibility of active sites for Na intercalation, due to the increase of extra carbonaceous material inside the pores. High resolution synchrotron powder X-ray and pair distribution function analyses of the as-made and cycled electrodes reveal the structure maintains the long-range order with progressivemore » cycling. This finding suggests that careful consideration of all variables in battery components, and especially electrolyte selection can lead to greatly improved performances.« less

A 5 x 40 cm rectangular-beam multipole ion source

NASA Technical Reports Server (NTRS)

Robinson, R. S.; Kaufman, H. R.; Haynes, C. M.

1981-01-01

A rectangular ion source particularly suited for the continuous sputter processing of materials over a wide area is discussed. A multipole magnetic field configuration was used to design an ion source with a 5 x 40 cm beam area, while a three-grid ion optics system was used to maximize ion current density at the design ion energy of 500 eV. An average extracted current density of about 4 mA/sq cm could be obtained from 500 eV Ar ions. The difference between the experimental performance and the design value of 6 mA/sq cm is attributed to grid misalignment due to thermal expansion. The discharge losses at typical operating conditions ranged from about 600 to 1000 eV/ion, in reasonable agreement with the design value of 800 eV/ion. The use of multiple rectangular-beam ion sources to process wider areas than would be possible with a single source was also studied, and the most uniform coverage was found to be obtainable with a 0 to 2 cm overlap.

Static time-of-flight secondary ion mass spectrometry analysis of microelectronics related substrates using a polyatomic ion source

NASA Astrophysics Data System (ADS)

Ravanel, X.; Trouiller, C.; Juhel, M.; Wyon, C.; Kwakman, L. F. Tz.; Léonard, D.

2008-12-01

Recent time-of-flight secondary ion mass spectrometry studies using primary ion cluster sources such as Au n+, SF 5+, Bi n+ or C 60+ have shown the great advantages in terms of secondary ion yield enhancement and ion formation efficiency of polyatomic ion sources as compared to monoatomic ion sources like the commonly used Ga +. In this work, the effective gains provided by such a source in the static ToF-SIMS analysis of microelectronics devices were investigated. Firstly, the influence of the number of atoms in the primary cluster ion on secondary ion formation was studied for physically adsorbed di-isononyl phthalate (DNP) (plasticizer) and perfluoropolyether (PFPE). A drastic increase in secondary ion formation efficiency and a much lower detection limit were observed when using a polyatomic primary ion. Moreover, the yield of the higher mass species was much enhanced indicating a lower degree of fragmentation that can be explained by the fact that the primary ion energy is spread out more widely, or that there is a lower energy per incoming ion. Secondly, the influence of the number of Bi atoms in the Bi n primary ion on the information depth was studied using reference thermally grown silicon oxide samples. The information depth provided by a Bi n cluster was shown to be lowered when the number of atoms in the aggregate was increased.

Operation Status of the J-PARC Negative Hydrogen Ion Source

NASA Astrophysics Data System (ADS)

Oguri, H.; Ikegami, K.; Ohkoshi, K.; Namekawa, Y.; Ueno, A.

2011-09-01

A cesium-free negative hydrogen ion source driven with a lanthanum hexaboride (LaB6) filament is being operated without any serious trouble for approximately four years in J-PARC. Although the ion source is capable of producing an H- ion current of more than 30 mA, the current is routinely restricted to approximately 16 mA at present for the stable operation of the RFQ linac which has serious discharge problem from September 2008. The beam run is performed during 1 month cycle, which consisted of a 4-5 weeks beam operation and a few days down-period interval. At the recent beam run, approximately 700 h continuous operation was achieved. At every runs, the beam interruption time due to the ion source failure is a few hours, which correspond to the ion source availability of more than 99%. The R&D work is being performed in parallel with the operation in order to enhance the further beam current. As a result, the H- ion current of 61 mA with normalized rms emittance of 0.26 πmm.mrad was obtained by adding a cesium seeding system to a J-PARC test ion source which has the almost same structure with the present J-PARC ion source.

A Collison nebulizer as an ion source for mass spectrometry analysis

NASA Astrophysics Data System (ADS)

Pervukhin, V. V.; Sheven', D. G.; Kolomiets, Yu. N.

2014-12-01

It is proposed to use a Collison nebulizer as a source of ionization for mass-spectrometry with ionization at atmospheric pressure. This source does not require an electric voltage, radioactive sources, heaters, or liquid pumps. It is shown that the number of ions produced by the Collison nebulizer is ten times greater than the quantity of ions produced by the 63Ni radioactive source and three to four times greater than the number of ions produced with sonic ionization devices.

Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

PubMed

Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

2008-02-01

There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL (invited)a)

NASA Astrophysics Data System (ADS)

Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Guo, X. H.; Cao, Y.; Lu, W.; Zhang, Z. M.; Yuan, P.; Song, M. T.; Zhao, H. Y.; Jin, T.; Shang, Y.; Zhan, W. L.; Wei, B. W.; Xie, D. Z.

2008-02-01

There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6T at injection, 2.2T at extraction, and a radial sextupole field of 2.0T at plasma chamber wall. During the commissioning phase at 18GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5kW by two 18GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810eμA of O7+, 505eμA of Xe20+, 306eμA of Xe27+, and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

Synthetic oligomer analysis using atmospheric pressure photoionization mass spectrometry at different photon energies.

PubMed

Desmazières, Bernard; Legros, Véronique; Giuliani, Alexandre; Buchmann, William

2014-01-15

Atmospheric pressure photoionization (APPI) followed by mass spectrometric detection was used to ionize a variety of polymers: polyethylene glycol, polymethyl methacrylate, polystyrene, and polysiloxane. In most cases, whatever the polymer or the solvent used (dichloromethane, tetrahydrofuran, hexane, acetone or toluene), only negative ion mode produced intact ions such as chlorinated adducts, with no or few fragmentations, in contrast to the positive ion mode that frequently led to important in-source fragmentations. In addition, it was shown that optimal detection of polymer distributions require a fine tuning of other source parameters such as temperature and ion transfer voltage. Series of mass spectra were recorded in the negative mode, in various solvents (dichloromethane, tetrahydrofuran, hexane, toluene, and acetone), by varying the photon energy from 8eV up to 10.6eV using synchrotron radiation. To these solvents, addition of a classical APPI dopant (toluene or acetone) was not necessary. Courtesy of the synchrotron radiation, it was demonstrated that the photon energy required for an efficient ionization of the polymer was correlated to the ionization energy of the solvent. As commercial APPI sources typically use krypton lamps with energy fixed at 10eV and 10.6eV, the study of the ionization of polymers over a wavelength range allowed to confirm and refine the previously proposed ionization mechanisms. Moreover, the APPI source can efficiently be used as an interface between size exclusion chromatography or reverse phase liquid chromatography and MS for the study of synthetic oligomers. However, the photoionization at fixed wavelength of polymer standards with different molecular weights showed that it was difficult to obtain intact ionized oligomers with molecular weights above a few thousands. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of mini linac-based positron source and an efficient positronium convertor for positively charged antihydrogen production

NASA Astrophysics Data System (ADS)

Muranaka, T.; Debu, P.; Dupré, P.; Liszkay, L.; Mansoulie, B.; Pérez, P.; Rey, J. M.; Ruiz, N.; Sacquin, Y.; Crivelli, P.; Gendotti, U.; Rubbia, A.

2010-04-01

We have installed in Saclay a facility for an intense positron source in November 2008. It is based on a compact 5.5 MeV electron linac connected to a reaction chamber with a tungsten target inside to produce positrons via pair production. The expected production rate for fast positrons is 5·1011 per second. The study of moderation of fast positrons and the construction of a slow positron trap are underway. In parallel, we have investigated an efficient positron-positronium convertor using porous silica materials. These studies are parts of a project to produce positively charged antihydrogen ions aiming to demonstrate the feasibility of a free fall antigravity measurement of neutral antihydrogen.

Composition of inner-source heavy pickup ions at 1 AU: SOHO/CELIAS/CTOF observations. Implications for the production mechanisms

NASA Astrophysics Data System (ADS)

Taut, A.; Berger, L.; Drews, C.; Wimmer-Schweingruber, R. F.

2015-04-01

Context. Pickup ions in the inner heliosphere mainly originate in two sources, one interstellar and one in the inner solar system. In contrast to the interstellar source that is comparatively well understood, the nature of the inner source has not been clearly identified. Former results obtained with the Solar Wind Ion Composition Spectrometer on-board the Ulysses spacecraft revealed that the composition of inner-source pickup ions is similar, but not equal, to the elemental solar-wind composition. These observations suffered from very low counting statistics of roughly one C+ count per day. Aims: Because the composition of inner-source pickup ions could lead to identifying their origin, we used data from the Charge-Time-Of-Flight sensor on-board the Solar and Heliospheric Observatory. It offers a large geometry factor that results in about 100 C+ counts per day combined with an excellent mass-per-charge resolution. These features enable a precise determination of the inner-source heavy pickup ion composition at 1 AU. To address the production mechanisms of inner-source pickup ions, we set up a toy model based on the production scenario involving the passage of solar-wind ions through thin dust grains to explain the observed deviations of the inner-source PUI and the elemental solar-wind composition. Methods: An in-flight calibration of the sensor allows identification of heavy pickup ions from pulse height analysis data by their mass-per-charge. A statistical analysis was performed to derive the inner-source heavy pickup ion relative abundances of N+, O+, Ne+, Mg+, Mg2+, and Si+ compared to C+. Results: Our results for the inner-source pickup ion composition are in good agreement with previous studies and confirm the deviations from the solar-wind composition. The large geometry factor of the Charge-Time-of-Flight sensor even allowed the abundance ratios of the two most prominent pickup ions, C+ and O+, to be investigated at varying solar-wind speeds. We found that the O+/C+ ratio increases systematically with higher solar-wind speeds. This observation is an unprecedented feature characterising the production of inner-source pickup ions. Comparing our observations to the toy model results, we find that both the deviation from the solar-wind composition and the solar-wind-speed dependent O+/C+ ratio can be explained.

Development of a Compact Neutron Generator to be Used For Associated Particle Imaging Utilizing a RF-Driven Ion Source

NASA Astrophysics Data System (ADS)

Wu, Ying

2009-11-01

The development of a prototype compact neutron generator for the application of associated particle imaging (API) to be used for explosive and contraband detection will be presented. The API technique makes use of the 3.5 MeV alpha particles that are produced simultaneously with the 14 MeV neutrons in the deuterium-tritium (^2D(^3T,n)^4α) fusion reaction to determine the direction of the neutrons and reduce background noise. This method determines the spatial position of each neutron interaction and requires the neutrons to be generated from a small spot in order to achieve high spatial resolution. In this work an axial type neutron generator was designed and built with a predicted neutron yield of 10^8 n/s for a 50 μA D/T ion beam current accelerated to 80 kV. It was shown that the measured yield for a D/D gas filled generator was 2x10^5n/s, which scales to 2x10^7 n/s if a D/T gas fill is used. The generator utilizes an RF planar spiral antenna at 13.56 MHz to create a highly efficient inductively coupled plasma at the ion source. Experimental results show that beams with an atomic ion fraction of > 80% can be obtained with only 100 watts of RF power in the ion source. A single acceleration gap with a secondary electron suppression electrode is used in the acceleration column, to suppress secondary backscattered electrons produced at the target. Initial measurements of the neutron generator performance including the beam spot size and neutron yield under sealed operation will be discussed, along with suggestions for future improvements.

Simulation of cesium injection and distribution in rf-driven ion sources for negative hydrogen ion generation.

PubMed

Gutser, R; Fantz, U; Wünderlich, D

2010-02-01

Cesium seeded sources for surface generated negative hydrogen ions are major components of neutral beam injection systems in future large-scale fusion experiments such as ITER. Stability and delivered current density depend highly on the cesium conditions during plasma-on and plasma-off phases of the ion source. The Monte Carlo code CSFLOW3D was used to study the transport of neutral and ionic cesium in both phases. Homogeneous and intense flows were obtained from two cesium sources in the expansion region of the ion source and from a dispenser array, which is located 10 cm in front of the converter surface.

Evolution of Instrumentation for the Study of Gas-Phase Ion/Ion Chemistry via Mass Spectrometry

PubMed Central

Xia, Yu; McLuckey, Scott A.

2008-01-01

The scope of gas phase ion/ion chemistry accessible to mass spectrometry is largely defined by the available tools. Due to the development of novel instrumentation, a wide range of reaction phenomenologies have been noted, many of which have been studied extensively and exploited for analytical applications. This perspective presents the development of mass spectrometry-based instrumentation for the study of the gas phase ion/ion chemistry in which at least one of the reactants is multiply-charged. The instrument evolution is presented within the context of three essential elements required for any ion/ion reaction study: the ionization source(s), the reaction vessel or environment, and the mass analyzer. Ionization source arrangements have included source combinations that allow for reactions between multiply charged ions of one polarity and singly charged ions of opposite polarity, arrangements that enable the study of reactions of multiply charged ions of opposite polarity, and most recently, arrangements that allow for ion formation from more than two ion sources. Gas phase ion/ion reaction studies have been performed at near atmospheric pressure in flow reactor designs and within electrodynamic ion traps operated in the mTorr range. With ion trap as a reaction vessel, ionization and reaction processes can be independently optimized and ion/ion reactions can be implemented within the context of MSn experiments. Spatial separation of the reaction vessel from the mass analyzer allows for the use of any form of mass analysis in conjunction with ion/ion reactions. Time-of-flight mass analysis, for example, has provided significant improvements in mass analysis figures of merit relative to mass filters and ion traps. PMID:18083527

Recent operation of the FNAL magnetron H- ion source

NASA Astrophysics Data System (ADS)

Karns, P. R.; Bollinger, D. S.; Sosa, A.

2017-08-01

This paper will detail changes in the operational paradigm of the Fermi National Accelerator Laboratory (FNAL) magnetron H- ion source due to upgrades in the accelerator system. Prior to November of 2012 the H- ions for High Energy Physics (HEP) experiments were extracted at ˜18 keV vertically downward into a 90 degree bending magnet and accelerated through a Cockcroft-Walton accelerating column to 750 keV. Following the upgrade in the fall of 2012 the H- ions are now directly extracted from a magnetron at 35 keV and accelerated to 750 keV by a Radio Frequency Quadrupole (RFQ). This change in extraction energy as well as the orientation of the ion source required not only a redesign of the ion source, but an updated understanding of its operation at these new values. Discussed in detail are the changes to the ion source timing, arc discharge current, hydrogen gas pressure, and cesium delivery system that were needed to maintain consistent operation at >99% uptime for HEP, with an increased ion source lifetime of over 9 months.

Design of a compact all-permanent magnet ECR ion source injector for ReA at the MSU NSCL

NASA Astrophysics Data System (ADS)

Pham, Alfonse N.; Leitner, Daniela; Glennon, Patrick; Ottarson, Jack; Lawton, Don; Portillo, Mauricio; Machicoane, Guillaume; Wenstrom, John; Lajoie, Andrew

2016-06-01

The design of a compact all-permanent magnet electron cyclotron resonance (ECR) ion source injector for the ReAccelerator Facility (ReA) at the Michigan State University (MSU) National Superconducting Cyclotron Laboratory (NSCL) is currently being carried out. The ECR ion source injector will complement the electron beam ion trap (EBIT) charge breeder as an off-line stable ion beam injector for the ReA linac. The objective of the ECR ion source injector is to provide continuous-wave beams of heavy ions from hydrogen to masses up to 136Xe within the ReA charge-to-mass ratio (Q / A) operational range from 0.2 to 0.5. The ECR ion source will be mounted on a high-voltage platform that can be adjusted to obtain the required 12 keV/u injection energy into a room temperature radio-frequency quadrupole (RFQ) for further acceleration. The beam line consists of a 30 kV tetrode extraction system, mass analyzing section, and optical matching section for injection into the existing ReA low energy beam transport (LEBT) line. The design of the ECR ion source and the associated beam line are discussed.

Bright focused ion beam sources based on laser-cooled atoms

PubMed Central

McClelland, J. J.; Steele, A. V.; Knuffman, B.; Twedt, K. A.; Schwarzkopf, A.; Wilson, T. M.

2016-01-01

Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga+ liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future. PMID:27239245

Bright focused ion beam sources based on laser-cooled atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

McClelland, J. J.; Wilson, T. M.; Steele, A. V.

2016-03-15

Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of themore » industry standard Ga{sup +} liquid metal ion source. In this review, we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.« less

Beam current enhancement of microwave plasma ion source utilizing double-port rectangular cavity resonator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Yuna; Park, Yeong-Shin; Jo, Jong-Gab

2012-02-15

Microwave plasma ion source with rectangular cavity resonator has been examined to improve ion beam current by changing wave launcher type from single-port to double-port. The cavity resonators with double-port and single-port wave launchers are designed to get resonance effect at TE-103 mode and TE-102 mode, respectively. In order to confirm that the cavities are acting as resonator, the microwave power for breakdown is measured and compared with the E-field strength estimated from the HFSS (High Frequency Structure Simulator) simulation. Langmuir probe measurements show that double-port cavity enhances central density of plasma ion source by modifying non-uniform plasma density profilemore » of the single-port cavity. Correspondingly, beam current from the plasma ion source utilizing the double-port resonator is measured to be higher than that utilizing single-port resonator. Moreover, the enhancement in plasma density and ion beam current utilizing the double-port resonator is more pronounced as higher microwave power applied to the plasma ion source. Therefore, the rectangular cavity resonator utilizing the double-port is expected to enhance the performance of plasma ion source in terms of ion beam extraction.« less

Beam current enhancement of microwave plasma ion source utilizing double-port rectangular cavity resonator.

PubMed

Lee, Yuna; Park, Yeong-Shin; Jo, Jong-Gab; Yang, J J; Hwang, Y S

2012-02-01

Microwave plasma ion source with rectangular cavity resonator has been examined to improve ion beam current by changing wave launcher type from single-port to double-port. The cavity resonators with double-port and single-port wave launchers are designed to get resonance effect at TE-103 mode and TE-102 mode, respectively. In order to confirm that the cavities are acting as resonator, the microwave power for breakdown is measured and compared with the E-field strength estimated from the HFSS (High Frequency Structure Simulator) simulation. Langmuir probe measurements show that double-port cavity enhances central density of plasma ion source by modifying non-uniform plasma density profile of the single-port cavity. Correspondingly, beam current from the plasma ion source utilizing the double-port resonator is measured to be higher than that utilizing single-port resonator. Moreover, the enhancement in plasma density and ion beam current utilizing the double-port resonator is more pronounced as higher microwave power applied to the plasma ion source. Therefore, the rectangular cavity resonator utilizing the double-port is expected to enhance the performance of plasma ion source in terms of ion beam extraction.

Comment on "Effects of Magnetic Field Gradient on Ion Beam Current in Cylindrical Hall Ion Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raitses, Y.; Smirnov A.; Fisch, N.J.

It is argued that the key difference of the cylindrical Hall thruster (CHT) as compared to the end-Hall ion source cannot be exclusively attributed to the magnetic field topology [Tang et al. J. Appl. Phys., 102, 123305 (2007)]. With a similar mirror-type topology, the CHT configuration provides the electric field with nearly equipotential magnetic field surfaces and a better suppression of the electron cross-field transport, as compared to both the end-Hall ion source and the cylindrical Hall ion source of Tang et al.

Interlaboratory study of the ion source memory effect in 36Cl accelerator mass spectrometry

NASA Astrophysics Data System (ADS)

Pavetich, Stefan; Akhmadaliev, Shavkat; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Buchriegler, Josef; Golser, Robin; Keddadouche, Karim; Martschini, Martin; Merchel, Silke; Rugel, Georg; Steier, Peter

2014-06-01

Understanding and minimization of contaminations in the ion source due to cross-contamination and long-term memory effect is one of the key issues for accurate accelerator mass spectrometry (AMS) measurements of volatile elements. The focus of this work is on the investigation of the long-term memory effect for the volatile element chlorine, and the minimization of this effect in the ion source of the Dresden accelerator mass spectrometry facility (DREAMS). For this purpose, one of the two original HVE ion sources at the DREAMS facility was modified, allowing the use of larger sample holders having individual target apertures. Additionally, a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, an interlaboratory comparison had been initiated. The long-term memory effect of the four Cs sputter ion sources at DREAMS (two sources: original and modified), ASTER (Accélérateur pour les Sciences de la Terre, Environnement, Risques) and VERA (Vienna Environmental Research Accelerator) had been investigated by measuring samples of natural 35Cl/37Cl-ratio and samples highly-enriched in 35Cl (35Cl/37Cl ∼ 999). Besides investigating and comparing the individual levels of long-term memory, recovery time constants could be calculated. The tests show that all four sources suffer from long-term memory, but the modified DREAMS ion source showed the lowest level of contamination. The recovery times of the four ion sources were widely spread between 61 and 1390 s, where the modified DREAMS ion source with values between 156 and 262 s showed the fastest recovery in 80% of the measurements.

Controlling Electron Backstreaming Phenomena Through the Use of a Transverse Magnetic Field

NASA Technical Reports Server (NTRS)

Foster, John E.; Patterson, Michael J.

2002-01-01

DEEP-SPACE mission propulsion requirements can be satisfied by the use of high specific impulse systems such as ion thrusters. For such missions. however. the ion thruster will be required to provide thrust for long periods of time. To meet the long operation time and high-propellant throughput requirements, thruster lifetime must be increased. In general, potential ion thruster failure mechanisms associated with long-duration thrusting can be grouped into four areas: (1) ion optics failure; (2) discharge cathode failure; (3) neutralizer failure; and (4) electron backstreaming caused by accelerator grid aperture enlargement brought on by accelerator grid erosion. The work presented here focuses on electron backstreaming. which occurs when the potential at the center of an accelerator grid aperture is insufficient to prevent the backflow of electrons into the ion thruster. The likelihood of this occurring depends on ion source operation time. plasma density, and grid voltages, as accelerator grid apertures enlarge as a result of erosion. Electrons that enter the gap between the high-voltage screen and accelerator grids are accelerated to the energies approximately equal to the beam voltage. This energetic electron beam (typically higher than 1 kV) can damage not only the ion source discharge cathode assembly. but also any of the discharge surfaces upstream of the ion acceleration optics that the electrons happen to impact. Indeed. past backstreaming studies have shown that near the backstreaming limit, which corresponds to the absolute value of the accelerator grid voltage below which electrons can backflow into the thruster, there is a rather sharp rise in temperature at structures such as the cathode keeper electrode. In this respect operation at accelerator grid voltages near the backstreaming limit is avoided. Generally speaking, electron backstreaming is prevented by operating the accelerator grid at a sufficiently negative voltage to ensure a sufficiently negative aperture center potential. This approach can provide the necessary margin assuming an expected aperture enlargement. Operation at very negative accelerator grid voltages, however, enhances ion charge-exchange and direct impingement erosion of the accelerator grid. The focus of the work presented here is the mitigation of electron backstreaming by the use of a magnetic field. The presence of a magnetic field oriented perpendicular to the thruster axis can significantly decrease the magnitude of the backflowing electron current by significantly reducing the electron diffusion coefficient. Negative ion sources utilize this principle to reduce the fraction of electrons in the negative ion beam. The focus of these efforts has been on the attenuation of electron current diffusing from the discharge plasma into the negative ion extraction optics by placing the transverse magnetic field upstream of the extraction electrodes. In contrast. in the case of positive ion sources such as ion thrusters, the approach taken in the work presented here is to apply the transverse field downstream of the ion extraction system so as to prevent electrons from flowing back into the source. It was found in the work presented here that the magnetic field also reduces the absolute value of the electron backstreaming limit voltage. In this respect. the applied transverse magnetic field provides two mechanisms for electron backstreaming mitigation: (1) electron current attenuation and (2) backstreaming limit voltage shift. Such a shift to less negative voltages can lead to reduced accelerator grid erosion rates.

Large area multiarc ion beam source {open_quote}MAIS{close_quote}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engelko, V.; Giese, H.; Schalk, S.

1996-12-31

A pulsed large area intense ion beam source is described, in which the ion emitting plasma is built up by an array of individual discharge units, homogeneously distributed over the surface of a common discharge electrode. A particularly advantageous feature of the source is that for plasma generation and subsequent acceleration of the ions only one common energy supply is necessary. This allows to simplify the source design and provides inherent synchronization of plasma production and ion extraction. The homogeneity of the plasma density was found to be superior to plasma sources using plasma expanders. Originally conceived for the productionmore » of proton beams, the source can easily be modified for the production of beams composed of carbon and metal ions or mixed ion species. Results of investigations of the source performance for the production of a proton beam are presented. The maximum beam current achieved to date is of the order of 100 A, with a particle kinetic energy of 15 - 30 keV and a pulse length in the range of 10 {mu}s.« less

Progress of superconducting electron cyclotron resonance ion sources at Institute of Modern Physics (IMP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, L., E-mail: sunlt@impcas.ac.cn; Feng, Y. C.; Zhang, W. H.

2014-02-15

Superconducting ECR ion sources can produce intense highly charged ion beams for the application in heavy ion accelerators. Superconducting Electron Resonance ion source with Advanced Design (SECRAL) is one of the few fully superconducting ECR ion sources that has been successfully built and put into routine operation for years. With enormous efforts and R and D work, promising results have been achieved with the ion source. Heated by the microwave power from a 7 kW/24 GHz gyrotron microwave generator, very intense highly charged gaseous ion beams have been produced, such as 455 eμA Xe{sup 27+}, 236 eμA Xe{sup 30+}, andmore » 64 eμA Xe{sup 35+}. Since heavy metallic ion beams are being more and more attractive and important for many accelerator projects globally, intensive studies have been made to produce highly charged heavy metal ion beams, such as those from bismuth and uranium. Recently, 420 eμA Bi{sup 30+} and 202 eμA U{sup 33+} have been produced with SECRAL source. This paper will present the latest results with SECRAL, and the operation status will be discussed as well. An introduction of recently started SECRAL II project will also be given in the presentation.« less

Progress of superconducting electron cyclotron resonance ion sources at Institute of Modern Physics (IMP).

PubMed

Sun, L; Lu, W; Feng, Y C; Zhang, W H; Zhang, X Z; Cao, Y; Zhao, Y Y; Wu, W; Yang, T J; Zhao, B; Zhao, H W; Ma, L Z; Xia, J W; Xie, D

2014-02-01

Superconducting ECR ion sources can produce intense highly charged ion beams for the application in heavy ion accelerators. Superconducting Electron Resonance ion source with Advanced Design (SECRAL) is one of the few fully superconducting ECR ion sources that has been successfully built and put into routine operation for years. With enormous efforts and R&D work, promising results have been achieved with the ion source. Heated by the microwave power from a 7 kW/24 GHz gyrotron microwave generator, very intense highly charged gaseous ion beams have been produced, such as 455 eμA Xe(27+), 236 eμA Xe(30+), and 64 eμA Xe(35+). Since heavy metallic ion beams are being more and more attractive and important for many accelerator projects globally, intensive studies have been made to produce highly charged heavy metal ion beams, such as those from bismuth and uranium. Recently, 420 eμA Bi(30+) and 202 eμA U(33+) have been produced with SECRAL source. This paper will present the latest results with SECRAL, and the operation status will be discussed as well. An introduction of recently started SECRAL II project will also be given in the presentation.

Production of N.sup.+ ions from a multicusp ion beam apparatus

DOEpatents

Leung, Ka-Ngo; Kunkel, Wulf B.; Walther, Steven R.

1993-01-01

A method of generating a high purity (at least 98%) N.sup.+ ion beam using a multicusp ion source (10) having a chamber (11) formed by a cylindrical chamber wall (12) surrounded by a plurality of magnets (13), a filament (57) centrally disposed in said chamber, a plasma electrode (36) having an extraction orifice (41) at one end of the chamber, a magnetic filter having two parallel magnets (21, 22) spaced from said plasma electrode (36) and dividing the chamber (11) into arc discharge and extraction regions. The method includes ionizing nitrogen gas in the arc discharge region of the chamber (11), maintaining the chamber wall (12) at a positive voltage relative to the filament (57) and at a magnitude for an optimum percentage of N.sup.+ ions in the extracted ion beams, disposing a hot liner (45) within the chamber and near the chamber wall (12) to limit recombination of N.sup.+ ions into the N.sub.2.sup.+ ions, spacing the magnets (21, 22) of the magnetic filter from each other for optimum percentage of N.sup.3 ions in the extracted ion beams, and maintaining a relatively low pressure downstream of the extraction orifice and of a magnitude (preferably within the range of 3-8.times.10.sup.-4 torr) for an optimum percentage of N.sup.+ ions in the extracted ion beam.

The effect of positive air ions on reproduction and growth in laboratory rats

NASA Astrophysics Data System (ADS)

Hinsull, S. M.; Head, E. L.

1986-03-01

The aim of the present investigation was to determine the growth rates, reproductive success and early mortality of laboratory rats maintained at 10,000 positive ions/ml over two generations. These findings were compared with those from animals maintained at ambient ion levels. The present work indicates that positive ions do not have any adverse effects on the reproductive capabilities or the growth of laboratory rats. In contrast it is shown that exposure to elevated levels of positive ions promotes overall growth, particularly in male rats. This action of positive ions increases with each successive generation exposed to the ions. It is suggested that the growth promoting effect of positive ions may be mediated via some modulation of the endocrine system.

Development of C⁶⁺ laser ion source and RFQ linac for carbon ion radiotherapy.

PubMed

Sako, T; Yamaguchi, A; Sato, K; Goto, A; Iwai, T; Nayuki, T; Nemoto, K; Kayama, T; Takeuchi, T

2016-02-01

A prototype C(6+) injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

NASA Astrophysics Data System (ADS)

Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

2016-02-01

A prototype C6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

Numerical Analysis of Plasma Transport in Tandem Volume Magnetic Multicusp Ion Sources

DTIC Science & Technology

1992-03-01

the results of the model are qualitatively correct. Boltzmann Equation, Ion Sources, Plasma Simulation, Electron Temperature, Plasma Density, Ion Temperature, Hydrogen Ions, Magnetic Filters, Hydrogen Plasma Chemistry .

Beam characterization at BATMAN for variation of the Cs evaporation asymmetry and comparing two driver geometries

NASA Astrophysics Data System (ADS)

Aza, E.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Fantz, U.

2017-08-01

The properties of the negative hydrogen ion beam produced by the scaled prototype ITER NBI source at the BATMAN testbed were investigated by means of two beam diagnostics: Beam Emission Spectroscopy (BES) and a calorimeter. Two modifications to the prototype were applied. The first was the installation of a second Cs oven at the bottom part of the backplate in addition to the standard one at the upper part of the backplate varying the Cs evaporation asymmetry inside the source. The second consisted in the replacement of the cylindrical driver with a larger racetrack-shaped RF driver and placing a single Cs oven in a central position at the backplate of the driver. The resulting beam characteristics are discussed and compared with those obtained with the previous source design. The position of the Cs oven and the different driver size and geometry appear not to influence the beam profile and the beam deflection for a well-conditioned source.

The Dartmouth Elephant plasma facility

NASA Astrophysics Data System (ADS)

Lynch, K. A.

2017-12-01

The Elephant facility in the Dartmouth Dept of Physics and Astronomyis a 1m by 2m chamber with a microwave-resonant plasma source togetherwith a higher energy electron/ion electrostatic gun. In this chamber weaim to re-create features of the auroral ionosphere including both thethermal plasma background, and the precipitating energetic auroral beam.We can manipulate the position and attitude of various sensors withinthe chamber and monitor their response to the various sources. Recentefforts have focussed on the sheath environment near and around thermalion RPA sensors and the small payloads which carry them into theionosphere.

Computer Modeling of High-Intensity Cs-Sputter Ion Sources

NASA Astrophysics Data System (ADS)

Brown, T. A.; Roberts, M. L.; Southon, J. R.

The grid-point mesh program NEDLab has been used to computer model the interior of the high-intensity Cs-sputter source used in routine operations at the Center for Accelerator Mass Spectrometry (CAMS), with the goal of improving negative ion output. NEDLab has several features that are important to realistic modeling of such sources. First, space-charge effects are incorporated in the calculations through an automated ion-trajectories/Poissonelectric-fields successive-iteration process. Second, space charge distributions can be averaged over successive iterations to suppress model instabilities. Third, space charge constraints on ion emission from surfaces can be incorporate under Child's Law based algorithms. Fourth, the energy of ions emitted from a surface can be randomly chosen from within a thermal energy distribution. And finally, ions can be emitted from a surface at randomized angles The results of our modeling effort indicate that significant modification of the interior geometry of the source will double Cs+ ion production from our spherical ionizer and produce a significant increase in negative ion output from the source.

Performance test of electron cyclotron resonance ion sources for the Hyogo Ion Beam Medical Center

NASA Astrophysics Data System (ADS)

Sawada, K.; Sawada, J.; Sakata, T.; Uno, K.; Okanishi, K.; Harada, H.; Itano, A.; Higashi, A.; Akagi, T.; Yamada, S.; Noda, K.; Torikoshi, M.; Kitagawa, A.

2000-02-01

Two electron cyclotron resonance (ECR) ion sources were manufactured for the accelerator facility at the Hyogo Ion Beam Medical Center. H2+, He2+, and C4+ were chosen as the accelerating ions because they have the highest charge to mass ratio among ion states which satisfy the required intensity and quality. The sources have the same structure as the 10 GHz ECR source at the Heavy Ion Medical Accelerator in Chiba except for a few improvements in the magnetic structure. Their performance was investigated at the Sumitomo Heavy Industries factory before shipment. The maximum intensity was 1500 μA for H2+, 1320 μA for He2+, and 580 μA for C4+ at the end of the ion source beam transport line. These are several times higher than required. Sufficient performance was also observed in the flatness and long-term stability of the pulsed beams. These test results satisfy the requirements for medical use.

H- Ion Sources for High Intensity Proton Drivers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Rolland Paul; Dudnikov, Vadim

2015-02-20

Existing RF Surface Plasma Sources (SPS) for accelerators have specific efficiencies for H + and H - ion generation around 3 to 5 mA/cm 2 per kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) SPS described here was developed to improve H- ion production efficiency, reliability and availability for pulsed operation as used in the ORNL Spallation Neutron Source . At low RF power, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm 2 per kW of RF power at 13.56more » MHz. Initial cesiation of the SPS was performed by heating cesium chromate cartridges by discharge as was done in the very first versions of the SPS. A small oven to decompose cesium compounds and alloys was developed and tested. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power 1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with 4 kW RF power in the plasma and 250 Gauss longitudinal magnetic field. The ratio of electron current to negative ion current was improved from 30 to 2. Stable generation of H- beam without intensity degradation was demonstrated in the aluminum nitride (AlN) discharge chamber for 32 days at high discharge power in an RF SPS with an external antenna. Some modifications were made to improve the cooling and cesiation stability. The extracted collector current can be increased significantly by optimizing the longitudinal magnetic field in the discharge chamber. While this project demonstrated the advantages of the pulsed version of the SA RF SPS as an upgrade to the ORNL Spallation Neutron Source, it led to a possibility for upgrades to CW machines like the many cyclotrons used for commercial applications. Four appendices contain important details of the work carried out under this grant.« less

High-voltage terminal test of a test stand for a 1-MV electrostatic accelerator

NASA Astrophysics Data System (ADS)

Park, Sae-Hoon; Kim, Yu-Seok

2015-10-01

The Korea Multipurpose Accelerator Complex has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source and accelerating tube will be installed in a high-pressure vessel. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz radio-frequency power supply, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. The results of the 300-kV high-voltage terminal tests are presented in this paper.

Electron cyclotron resonance ion source for high currents of mono- and multicharged ion and general purpose unlimited lifetime application on implantation devices

NASA Astrophysics Data System (ADS)

Bieth, C.; Bouly, J. L.; Curdy, J. C.; Kantas, S.; Sortais, P.; Sole, P.; Vieux-Rochaz, J. L.

2000-02-01

The electron cyclotron resonance (ECR) ion sources were originally developed for high energy physic applications. They are used as injectors on linear accelerators and cyclotrons to further increase the particle energy via high charge state ions. This ECR technology is well suited for sources placed on a high voltage platform where ac power available is limited by insulated transformers. The PANTECHNIK family of ion source with its wide range of ion beam (various charge states with various beam currents) offers new possibilities and perspectives in the field of ion implantation. In addition to all these possibilities, the PANTECHNIK ion sources have many other advantages like: a very long lifetime without maintenance expense, good stability, efficiency of ionization close to 100% (this improves the lifetime of the pumping system and other equipment), the possibility of producing ion beams with different energies, and a very good reproducibility. The main characteristics of sources like Nanogan or SuperNanogan will be recalled. We will especially present the results obtained with the new Microgan 10 GHz source that can be optimized for the production of high currents of monocharged ion, including reactive gas like BF3 (2 mA e of B+) or medium currents of low charge state like 0.5 mA e of Ar4+. The latest results obtained with Microgan 10 GHz show that it is possible to drive the source up to 30 mA e of total current, with an emittance of 150 π mm mrad at 40 kV and also to maintain the production of multicharged ions like Ar8+.

Multiwavelength Study of the Bright X-ray Source Population in the Interacting Galaxies NGC 5774/NGC 5775

NASA Technical Reports Server (NTRS)

Ghosh, Kajal K.; Swartz, Douglas A.; Tennant, Allyn F.; Saripalli, Lakshmi; Gandhi, Poshak; Foellmi, Cedric; Gutierrez, Carlos M.; Lopez-Corredoira, Martin

2006-01-01

The X-ray source population in the field of the interacting pair of galaxies NGC 5774/5775 is reported. A total of 49 discrete sources are detected, including 12 ultraluminous X-ray source candidates with lum inosities above 10(exp 39)erg/s in the 0.5 - 8.0 keV X-ray band. Several of these latter are transient X-ray sources that fall below detect ion levels in one of two X-ray observations spaced 15 months apart. X-ray source positions are mapped onto optical and radio images to sear ch for potential counterparts. Eleven sources have optically-bright c ounterparts. Optical colors are used to differentiate these sources, which are mostly located outside the optical extent of the interacting galaxies, as potential globular clusters (3 sources) and quasars (5) . Follow-up optical spectroscopy confirms two of the latter are background quasars.

Time-resolved magnetic spectrometer measurements of the SABRE positive polarity magnetically insulated transmission line voltage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menge, P.R.; Cuneo, M.E.; Hanson, D.L.

A magnetic spectrometer has been fielded on the coaxial magnetically insulated transmission line (MITL) of the SABRE ten-cavity inductive voltage adder operated in positive polarity (6 MV, 300 kA, 50 ns). Located 1 m upstream from an extraction ion diode, this diagnostic is capable of measuring the SABRE voltage pulse with a 2 ns resolution. Ions (protons and carbon) from either a flashover or plasma gun source are accelerated from the inner anode across the gap to the outer cathode and into a drift tube terminated by the magnetic spectrometer. The magnetically deflected ions are recorded on up to sixteenmore » PIN diodes (diameter = 1 mm, thickness = 35 {mu}). The voltage waveform is produced from the time-of-flight information. Results confirm previous observations of a vacuum wave precursor separated from the magnetically insulated wave. Verification of upstream precursor erosion techniques are possible with this instrument. Measurements of peak voltage show good agreement with other time-integrated voltage diagnostics. Comparisons with theoretical voltage predictions derived from a flow impedance model of MITL behavior will be presented.« less

A comprehensive library-based, automated screening procedure for 46 synthetic cannabinoids in serum employing liquid chromatography-quadrupole ion trap mass spectrometry with high-temperature electrospray ionization.

PubMed

Huppertz, Laura M; Kneisel, Stefan; Auwärter, Volker; Kempf, Jürgen

2014-02-01

Considering the vast variety of synthetic cannabinoids and herbal mixtures - commonly known as 'Spice' or 'K2' - on the market and the resulting increase of severe intoxications related to their consumption, there is a need in clinical and forensic toxicology for comprehensive up-to-date screening methods. The focus of this project aimed at developing and implementing an automated screening procedure for the detection of synthetic cannabinoids in serum using a liquid chromatography-ion trap-MS (LC-MS(n)) system and a spectra library-based approach, currently including 46 synthetic cannabinoids and 8 isotope labelled analogues. In the process of method development, a high-temperature ESI source (IonBooster(TM), Bruker Daltonik) and its effects on the ionization efficiency of the investigated synthetic cannabinoids were evaluated and compared to a conventional ESI source. Despite their structural diversity, all investigated synthetic cannabinoids benefitted from high-temperature ionization by showing remarkably higher MS intensities compared to conventional ESI. The employed search algorithm matches retention time, MS and MS(2)/MS(3) spectra. With the utilization of the ionBooster source, limits for the automated detection comparable to cut-off values of routine MRM methods were achieved for the majority of analytes. Even compounds not identified when using a conventional ESI source were detected using the ionBooster-source. LODs in serum range from 0.1 ng/ml to 0.5 ng/ml. The use of parent compounds as analytical targets offers the possibility of instantly adding new emerging compounds to the library and immediately applying the updated method to serum samples, allowing the rapid adaptation of the screening method to ongoing forensic or clinical requirements. The presented approach can also be applied to other specimens, such as oral fluid or hair, and herbal mixtures and was successfully applied to authentic serum samples. Quantitative MRM results of samples with analyte concentrations above the determined LOD were confirmed as positive findings by the presented method. Copyright © 2014 John Wiley & Sons, Ltd.

Multiple sulfur isotope determination on SO2 gas

NASA Astrophysics Data System (ADS)

Halas, Stanislaw; Pienkos, Tomasz

2017-04-01

The principal motivation of this study is to apply SO2 gas in the multiple isotope analysis (i.e. simultaneous analysis of sulfur isotope ratios: 33S/32S , 34S/32S and 36S/32S) rather than SF6 gas. SO2 gas can be easily prepared from sulfides (Robinson and Kusakabe 1975) and from sulfates (Halas and Wolacewicz 1981), whilst the preparation of SF6 gas requires the use of a fluorination line (Ono et al. 2006) and a mass spectrometer with enhanced resolving power to resolve isotope peaks 33SF5- from 32SF5- (masses 128 and 127). In the patent application (Halas et al. 2016) we have described a new ion source which can be applied for analysis of gases. The new ion source significantly enhances generation, both positive and negative, ions in comparison to commonly used Nier type. The analyzed gas is admitted from a dual inlet system to the ion source through separate capillaries connected to the pneumatically operated changeover valve as described by Halas (1979). It is important to have SO2 samples well purified from volatiles which eliminates O2 interference at mass 32 peak. A great advantage of the isotope analysis on S+ instead on SO+ or SO2+spectra is that there is no need to keep constant oxygen isotopic composition in the SO2 gas. Usually sulfide and sulfate samples have different oxygen, but it doesn't matter in the case of analysis on S+. The achieved precision (1σ) on positive ion beams was better than 0.1‰ and 0.01‰ for δ36S and δ34S, respectively. Unfortunately δ33S cannot be measured in this way, because of formation of 32SH+ ions which interfere with 33S+. The details of the design of the ion source, vacuum system and electronic controllers are presented in the poster. We thank to Dr. Keith Hackley for donation of an old mass spectrometer to UMCS, on the basis of which we were able to develop the new instrument. This study was supported by NCN project 2013/11/B/ST10/00250. References Hałas S., Pieńkos T., Pelc A., Wójtowicz A. (2016) Patent descriprtions P.416375 and P.417560. Halas S. and Wolacewicz W. (1981) Direct extraction of sulfur dioxide from sulfates for isotopic analysis, Anal. Chem. 53: 686-689. Ono S., Wing B., Johnston D., Farquhar J.,Rumble D. (2006) Mass dependent fractionation of quadruple stable sulfur isotope system as anew tracer of sulfur biogeochemical cycles, Geochim. et Cosmochim. Acta 70: 2238-2252. Robinson B. and Kusakabe M. (1975) Quantitative preparation of sulfur dioxide, for 34S/32S analysis, from sulfides by combustion with cuprous oxide. Anal. Chem. 47:1179-1181.

Structural micro-porous carbon anode for rechargeable lithium-ion batteries

DOEpatents

Delnick, F.M.; Even, W.R. Jr.; Sylwester, A.P.; Wang, J.C.F.; Zifer, T.

1995-06-20

A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc. 6 figs.

A Penning sputter ion source with very low energy spread

NASA Astrophysics Data System (ADS)

Nouri, Z.; Li, R.; Holt, R. A.; Rosner, S. D.

2010-03-01

We have developed a version of the Frankfurt Penning ion source that produces ion beams with very low energy spreads of ˜3 eV, while operating in a new discharge mode characterized by very high pressure, low voltage, and high current. The extracted ions also comprise substantial metastable and doubly charged species. Detailed studies of the operating parameters of the source showed that careful adjustment of the magnetic field and gas pressure is critical to achieving optimum performance. We used a laser-fluorescence method of energy analysis to characterize the properties of the extracted ion beam with a resolving power of 1×10 4, and to measure the absolute ion beam energy to an accuracy of 4 eV in order to provide some insight into the distribution of plasma potential within the ion source. This characterization method is widely applicable to accelerator beams, though not universal. The low energy spread, coupled with the ability to produce intense ion beams from almost any gas or conducting solid, make this source very useful for high-resolution spectroscopic measurements on fast-ion beams.

A combined thermal dissociation and electron impact ionization source for radioactive ion beam generation{sup a}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alton, G.D.; Williams, C.

1996-04-01

The probability for simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecular feed materials with conventional, hot-cathode, electron-impact ion sources is low and consequently, the ion beams from these sources often appear as mixtures of several molecular sideband beams. This fragmentation process leads to dilution of the intensity of the species of interest for radioactive ion beam (RIB) applications where beam intensity is at a premium. We have conceived an ion source that combines the excellent molecular dissociation properties of a thermal dissociator and the high ionization efficiency characteristics of an electron impact ionization source that will, inmore » principle, overcome this handicap. The source concept will be evaluated as a potential candidate for use for RIB generation at the Holifield Radioactive Ion Beam Facility, now under construction at the Oak Ridge National Laboratory. The design features and principles of operation of the source are described in this article. {copyright} {ital 1996 American Institute of Physics.}« less

A combined thermal dissociation and electron impact ionization source for radioactive ion beam generation (abstract){sup a}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alton, G.D.; Williams, C.

1996-03-01

The probability for simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecular feed materials with conventional, hot-cathode, electron-impact ion sources is low and consequently, the ion beams from these sources often appear as mixtures of several molecular sideband beams. This fragmentation process leads to dilution of the intensity of the species of interest for radioactive ion beam (RIB) applications where beam intensity is at a premium. We have conceived an ion source that combines the excellent molecular dissociation properties of a thermal dissociator and the high ionization efficiency characteristics of an electron impact ionization source that will, inmore » principle, overcome this handicap. The source concept will be evaluated as a potential candidate for use for RIB generation at the Holifield Radioactive Ion Beam Facility, now under construction at the Oak Ridge National Laboratory. The design features and principles of operation of the source are described in this article. {copyright} {ital 1996 American Institute of Physics.}« less

RF H-minus ion source development in China spallation neutron source

NASA Astrophysics Data System (ADS)

Chen, W.; Ouyang, H.; Xiao, Y.; Liu, S.; Lü, Y.; Cao, X.; Huang, T.; Xue, K.

2017-08-01

China Spallation Neutron Source (CSNS) phase-I project currently uses a Penning surface plasma H- ion source, which has a life time of several weeks with occasional sparks between high voltage electrodes. To extend the life time of the ion source and prepare for the CSNS phase-II, we are trying to develop a RF negative hydrogen ion source with external antenna. The configuration of the source is similar to the DESY external antenna ion source and SNS ion source. However several changes are made to improve the stability and the life time. Firstly, Si3N4 ceramic with high thermal shock resistance, and high thermal conductivity is used for plasma chamber, which can endure an average power of 2000W. Secondly, the water-cooled antenna is brazed on the chamber to improve the energy efficiency. Thirdly, cesium is injected directly to the plasma chamber if necessary, to simplify the design of the converter and the extraction. Area of stainless steel exposed to plasma is minimized to reduce the sputtering and degassing. Instead Mo, Ta, and Pt coated materials are used to face the plasma, which makes the self-cleaning of the source possible.

High brightness--multiple beamlets source for patterned X-ray production

DOEpatents

Leung, Ka-Ngo [Hercules, CA; Ji, Qing [Albany, CA; Barletta, William A [Oakland, CA; Jiang, Ximan [El Cerrito, CA; Ji, Lili [Albany, CA

2009-10-27

Techniques for controllably directing beamlets to a target substrate are disclosed. The beamlets may be either positive ions or electrons. It has been shown that beamlets may be produced with a diameter of 1 .mu.m, with inter-aperture spacings of 12 .mu.m. An array of such beamlets, may be used for maskless lithography. By step-wise movement of the beamlets relative to the target substrate, individual devices may be directly e-beam written. Ion beams may be directly written as well. Due to the high brightness of the beamlets from extraction from a multicusp source, exposure times for lithographic exposure are thought to be minimized. Alternatively, the beamlets may be electrons striking a high Z material for X-ray production, thereafter collimated to provide patterned X-ray exposures such as those used in CAT scans. Such a device may be used for remote detection of explosives.

Characterization of Charge Separation in the Array of Micromachined UltraSonic Electrospray (AMUSE) Ion Source for Mass Spectrometry

PubMed Central

Forbes, Thomas P.; Dixon, R. Brent; Muddiman, David C.; Degertekin, F. Levent; Fedorov, Andrei G.

2009-01-01

An initial investigation into the effects of charge separation in the Array of Micromachined UltraSonic Electrospray (AMUSE) ion source is reported in order to gain understanding of ionization mechanisms and to improve analyte ionization efficiency and operation stability. In RF-only mode, AMUSE ejects on average, an equal number of slightly positive and slightly negative charged droplets due to random charge fluctuations, providing inefficient analyte ionization. Charge separation at the nozzle orifice is achieved by the application of an external electric field. By bringing the counter electrode close to the nozzle array, strong electric fields can be applied at relatively low DC potentials. It has been demonstrated, through a number of electrode/electrical potential configurations that increasing charge separation leads to improvement in signal abundance, signal-to-noise ratio, and signal stability. PMID:19525123

A high repetition deterministic single ion source

NASA Astrophysics Data System (ADS)

Sahin, C.; Geppert, P.; Müllers, A.; Ott, H.

2017-12-01

We report on a deterministic single ion source with high repetition rate and high fidelity. The source employs a magneto-optical trap, where ultracold rubidium atoms are photoionized. The electrons herald the creation of a corresponding ion, whose timing information is used to manipulate its trajectory in flight. We demonstrate an ion rate of up to 4× {10}4 {{{s}}}-1 and achieve a fidelity for single ion operation of 98%. The technique can be used for all atomic species, which can be laser-cooled, and opens up new applications in ion microscopy, ion implantation and surface spectroscopy.

Measurement and Visualization of Mass Transport for the Flowing Atmospheric Pressure Afterglow (FAPA) Ambient Mass-Spectrometry Source

PubMed Central

Pfeuffer, Kevin P.; Ray, Steven J.; Hieftje, Gary M.

2014-01-01

Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last nine years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification due to the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass-spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet. PMID:24658804

Measurement and visualization of mass transport for the flowing atmospheric pressure afterglow (FAPA) ambient mass-spectrometry source.

PubMed

Pfeuffer, Kevin P; Ray, Steven J; Hieftje, Gary M

2014-05-01

Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last 9 years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification because of the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet.

Measurement and Visualization of Mass Transport for the Flowing Atmospheric Pressure Afterglow (FAPA) Ambient Mass-Spectrometry Source

NASA Astrophysics Data System (ADS)

Pfeuffer, Kevin P.; Ray, Steven J.; Hieftje, Gary M.

2014-05-01

Ambient desorption/ionization mass spectrometry (ADI-MS) has developed into an important analytical field over the last 9 years. The ability to analyze samples under ambient conditions while retaining the sensitivity and specificity of mass spectrometry has led to numerous applications and a corresponding jump in the popularity of this field. Despite the great potential of ADI-MS, problems remain in the areas of ion identification and quantification. Difficulties with ion identification can be solved through modified instrumentation, including accurate-mass or MS/MS capabilities for analyte identification. More difficult problems include quantification because of the ambient nature of the sampling process. To characterize and improve sample volatilization, ionization, and introduction into the mass spectrometer interface, a method of visualizing mass transport into the mass spectrometer is needed. Schlieren imaging is a well-established technique that renders small changes in refractive index visible. Here, schlieren imaging was used to visualize helium flow from a plasma-based ADI-MS source into a mass spectrometer while ion signals were recorded. Optimal sample positions for melting-point capillary and transmission-mode (stainless steel mesh) introduction were found to be near (within 1 mm of) the mass spectrometer inlet. Additionally, the orientation of the sampled surface plays a significant role. More efficient mass transport resulted for analyte deposits directly facing the MS inlet. Different surfaces (glass slide and rough surface) were also examined; for both it was found that the optimal position is immediately beneath the MS inlet.

Bipolar Mass Spectrometry of Labile Coordination Complexes, Redox Active Inorganic Compounds, and Proteins Using a Glass Nebulizer for Sonic-Spray Ionization

NASA Astrophysics Data System (ADS)

Antonakis, Manolis M.; Tsirigotaki, Alexandra; Kanaki, Katerina; Milios, Constantinos J.; Pergantis, Spiros A.

2013-08-01

In this study, we report on the development of a novel nebulizer configuration for sonic-spray ionization (SSI) mass spectrometry (MS), more specifically for a version of SSI that is referred to as Venturi easy ambient sonic-spray ionization (V-EASI) MS. The developed nebulizer configuration is based on a commercially available pneumatic glass nebulizer that has been used extensively for aerosol formation in atomic spectrometry. In the present study, the nebulizer was modified in order to achieve efficient V-EASI-MS operation. Upon evaluating this system, it has been demonstrated that V-EASI-MS offers some distinct advantages for the analysis of coordination compounds and redox active inorganic compounds over the predominantly used electrospray ionization (ESI) technique. Such advantages, for this type of compounds, are demonstrated here for the first time. More specifically, a series of labile heptanuclear heterometallic [CuII 6LnIII] clusters held together with artificial amino acid ligands, in addition to easily oxidized inorganic oxyanions of selenium and arsenic, were analyzed. The observed advantages pertain to V-EASI appearing to be a "milder" ionization source than ESI, not requiring electrical potentials for gas phase ion formation, thus eliminating the possibility of unwanted redox transformations, allowing for the "simultaneous" detection of negative and positive ions (bipolar analysis) without the need to change source ionization conditions, and also not requiring the use of syringes and delivery pumps. Because of such features, especially because of the absence of ionization potentials, EASI can be operated with minimal requirements for source parameter optimization. We observed that source temperature and accelerating voltage do not seem to affect labile compounds to the extent they do in ESI-MS. In addition, bipolar analysis of proteins was demonstrated here by acquiring both positive and negative ion mass spectra from the same protein solutions, without the need to independently adjust solution and source conditions in each mode. Finally, the simple and efficient operation of a dual-nebulizer configuration was demonstrated for V-EASI-MS for the first time.

Bipolar mass spectrometry of labile coordination complexes, redox active inorganic compounds, and proteins using a glass nebulizer for sonic-spray ionization.

PubMed

Antonakis, Manolis M; Tsirigotaki, Alexandra; Kanaki, Katerina; Milios, Constantinos J; Pergantis, Spiros A

2013-08-01

In this study, we report on the development of a novel nebulizer configuration for sonic-spray ionization (SSI) mass spectrometry (MS), more specifically for a version of SSI that is referred to as Venturi easy ambient sonic-spray ionization (V-EASI) MS. The developed nebulizer configuration is based on a commercially available pneumatic glass nebulizer that has been used extensively for aerosol formation in atomic spectrometry. In the present study, the nebulizer was modified in order to achieve efficient V-EASI-MS operation. Upon evaluating this system, it has been demonstrated that V-EASI-MS offers some distinct advantages for the analysis of coordination compounds and redox active inorganic compounds over the predominantly used electrospray ionization (ESI) technique. Such advantages, for this type of compounds, are demonstrated here for the first time. More specifically, a series of labile heptanuclear heterometallic [Cu(II) 6Ln(III)] clusters held together with artificial amino acid ligands, in addition to easily oxidized inorganic oxyanions of selenium and arsenic, were analyzed. The observed advantages pertain to V-EASI appearing to be a "milder" ionization source than ESI, not requiring electrical potentials for gas phase ion formation, thus eliminating the possibility of unwanted redox transformations, allowing for the "simultaneous" detection of negative and positive ions (bipolar analysis) without the need to change source ionization conditions, and also not requiring the use of syringes and delivery pumps. Because of such features, especially because of the absence of ionization potentials, EASI can be operated with minimal requirements for source parameter optimization. We observed that source temperature and accelerating voltage do not seem to affect labile compounds to the extent they do in ESI-MS. In addition, bipolar analysis of proteins was demonstrated here by acquiring both positive and negative ion mass spectra from the same protein solutions, without the need to independently adjust solution and source conditions in each mode. Finally, the simple and efficient operation of a dual-nebulizer configuration was demonstrated for V-EASI-MS for the first time.

A high brightness source for nano-probe secondary ion mass spectrometry

NASA Astrophysics Data System (ADS)

Smith, N. S.; Tesch, P. P.; Martin, N. P.; Kinion, D. E.

2008-12-01

The two most prevalent ion source technologies in the field of surface analysis and surface machining are the Duoplasmatron and the liquid metal ion source (LMIS). There have been many efforts in this area of research to develop an alternative source [ S.K. Guharay, J. Orloff, M. Wada, IEEE Trans. Plasma Sci. 33 (6) (2005) 1911; N.S. Smith, W.P. Skoczylas, S.M. Kellogg, D.E. Kinion, P.P. Tesch, O. Sutherland, A. Aanesland, R.W. Boswell, J. Vac. Sci. Technol. B 24 (6) (2006) 2902-2906] with the brightness of a LMIS and yet the ability to produce secondary ion yield enhancing species such as oxygen. However, to date a viable alternative has not been realized. The high brightness and small virtual source size of the LMIS are advantageous for forming high resolution probes but a significant disadvantage when beam currents in excess of 100 nA are required, due to the effects of spherical aberration from the optical column. At these higher currents a source with a high angular intensity is optimal and in fact the relatively moderate brightness of today's plasma ion sources prevail in this operating regime. Both the LMIS and Duoplasmatron suffer from a large axial energy spread resulting in further limitations when forming focused beams at the chromatic limit where the figure-of-merit is inversely proportional to the square of the energy spread. Also, both of these ion sources operate with a very limited range of ion species. This article reviews some of the latest developments and some future potential in this area of instrument development. Here we present an approach to source development that could lead to oxygen ion beam SIMS imaging with 10 nm resolution, using a 'broad area' RF gas phase ion source.

Improving quantitative gas chromatography-electron ionization mass spectrometry results using a modified ion source: demonstration for a pharmaceutical application.

PubMed

D'Autry, Ward; Wolfs, Kris; Hoogmartens, Jos; Adams, Erwin; Van Schepdael, Ann

2011-07-01

Gas chromatography-mass spectrometry is a well established analytical technique. However, mass spectrometers with electron ionization sources may suffer from signal drifts, hereby negatively influencing quantitative performance. To demonstrate this phenomenon for a real application, a static headspace-gas chromatography method in combination with electron ionization-quadrupole mass spectrometry was optimized for the determination of residual dichloromethane in coronary stent coatings. Validating the method, the quantitative performance of an original stainless steel ion source was compared to that of a modified ion source. Ion source modification included the application of a gold coating on the repeller and exit plate. Several validation aspects such as limit of detection, limit of quantification, linearity and precision were evaluated using both ion sources. It was found that, as expected, the stainless steel ion source suffered from signal drift. As a consequence, non-linearity and high RSD values for repeated analyses were obtained. An additional experiment was performed to check whether an internal standard compound would lead to better results. It was found that the signal drift patterns of the analyte and internal standard were different, consequently leading to high RSD values for the response factor. With the modified ion source however, a more stable signal was observed resulting in acceptable linearity and precision. Moreover, it was also found that sensitivity improved compared to the stainless steel ion source. Finally, the optimized method with the modified ion source was applied to determine residual dichloromethane in the coating of coronary stents. The solvent was detected but found to be below the limit of quantification. Copyright © 2011 Elsevier B.V. All rights reserved.

Operation of Lanzhou all permanent electron cyclotron resonance ion source No. 2 on 320 kV platform with highly charged ions.

PubMed

Lu, W; Li, J Y; Kang, L; Liu, H P; Li, H; Li, J D; Sun, L T; Ma, X W

2014-02-01

The 320 kV platform for multi-discipline research with highly charged ions is a heavy ion beam acceleration instrument developed by Institute of Modern Physics, which is dedicated to basic scientific researches such as plasma, atom, material physics, and astrophysics, etc. The platform has delivered ion beams of 400 species for 36,000 h. The average operation time is around 5000 h/year. With the beams provided by the platform, lots of outstanding progresses were made in various research fields. The ion source of the platform is an all-permanent magnet electron cyclotron resonance ion source, LAPECR2 (Lanzhou All Permanent ECR ion source No. 2). The maximum axial magnetic fields are 1.28 T at injection and 1.07 T at extraction, and the radial magnetic field is up to 1.21 T at the inner wall of the plasma chamber. The ion source is capable to produce low, medium, and high charge state gaseous and metallic ion beams, such as H(+), (40)Ar(8+), (129)Xe(30+), (209)Bi(33+), etc. This paper will present the latest result of LAPECR2 and the routine operation status for the high voltage platform.

Nb3Sn superconducting magnets for electron cyclotron resonance ion sources.

PubMed

Ferracin, P; Caspi, S; Felice, H; Leitner, D; Lyneis, C M; Prestemon, S; Sabbi, G L; Todd, D S

2010-02-01

Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb(3)Sn superconducting technology for several years. At the moment, Nb(3)Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb(3)Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb(3)Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb(3)Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell pretensioned with water-pressurized bladders, and we analyze the expected coil stresses with a two-dimensional finite element mechanical model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanesue, Takeshi; Ikeda, Shunsuke

A laser ion source is a promising candidate as an ion source for heavy ion inertial fusion (HIF), where a pulsed ultra-intense and low-charged heavy ion beam is required. It is a key development for a laser ion source to transport laser-produced plasma with a magnetic field to achieve a high current beam. The effect of a tapered magnetic field on laser produced plasma is demonstrated by comparing the results with a straight solenoid magnet. The magnetic field of interest is a wider aperture on a target side and narrower aperture on an extraction side. Furthermore, based on the experimentallymore » obtained results, the performance of a scaled laser ion source for HIF was estimated.« less

ION ACCELERATION SYSTEM

DOEpatents

Luce, J.S.; Martin, J.A.

1960-02-23

Well focused, intense ion beams are obtained by providing a multi- apertured source grid in front of an ion source chamber and an accelerating multi- apertured grid closely spaced from and in alignment with the source grid. The longest dimensions of the elongated apertures in the grids are normal to the direction of the magnetic field used with the device. Large ion currents may be withdrawn from the source, since they do not pass through any small focal region between the grids.

Scintillation screen applications in a vacuum arc ion source with composite hydride cathode

NASA Astrophysics Data System (ADS)

Wang, X. H.; Tuo, X. G.; Yang, Z.; Peng, Y. F.; Li, J.; Lv, H. Y.; Li, J. H.; Long, J. D.

2018-05-01

Vacuum arc ion source with composite hydride cathode was developed to produce intense ion beams which can be applied in particle accelerator injections. Beam profile and beam composition are two fundamental parameters of the beam for the vacuum arc ion source in such specific applications. An aluminum-coated scintillation screen with an ICCD camera readout was used to show the space-time distribution of the beam directly. A simple magnetic analysis assembly with the scintillation screen shows the beam composition information of this kind ion source. Some physical and technical issues are discussed and analyzed in the text.

Point-like neutron source based on high-current electron cyclotron resonance ion source with powerful millimeter wave plasma heating

NASA Astrophysics Data System (ADS)

Golubev, S. V.; Skalyga, V. A.; Izotov, I. V.; Sidorov, A. V.

2018-01-01

A possibility of an intense deuterium ion beam creation for a compact powerful point-like neutron source is discussed. The fusion takes place due to bombardment of deuterium (or tritium) loaded target by high-current focused deuterium ion beam with energy of 100 keV. The ways of high-current and low emittance ion beam formation from the plasma of quasi-gasdynamic ion source of a new generation based on an electron cyclotron resonance discharge in an open magnetic trap sustained by powerful microwave radiation are investigated.

Universal main magnetic focus ion source for production of highly charged ions

NASA Astrophysics Data System (ADS)

Ovsyannikov, V. P.; Nefiodov, A. V.; Levin, A. A.

2017-10-01

A novel room-temperature compact ion source has been developed for the efficient production of atomic ions by means of an electron beam with energy Ee and current density je controllable within wide ranges (100 eV ≲Ee ≲ 60 keV, 10 A/cm2 ≲je ≲ 20 kA/cm2). In the first experiments, the X-ray emission of Ir64+ ions has been measured. Based on a combination of two different techniques, the device can operate both as conventional Electron Beam Ion Source/Trap and novel Main Magnetic Focus Ion Source. The tunable electron-optical system allows for realizing laminar and turbulent electron flows in a single experimental setup. The device is intended primarily for fundamental and applied research at standard university laboratories.

Effect of tapered magnetic field on expanding laser-produced plasma for heavy-ion inertial fusion

DOE PAGES

Kanesue, Takeshi; Ikeda, Shunsuke

2016-12-20

A laser ion source is a promising candidate as an ion source for heavy ion inertial fusion (HIF), where a pulsed ultra-intense and low-charged heavy ion beam is required. It is a key development for a laser ion source to transport laser-produced plasma with a magnetic field to achieve a high current beam. The effect of a tapered magnetic field on laser produced plasma is demonstrated by comparing the results with a straight solenoid magnet. The magnetic field of interest is a wider aperture on a target side and narrower aperture on an extraction side. Furthermore, based on the experimentallymore » obtained results, the performance of a scaled laser ion source for HIF was estimated.« less

Thermal-electric numerical simulation of a surface ion source for the production of radioactive ion beams

NASA Astrophysics Data System (ADS)

Manzolaro, Mattia; Meneghetti, Giovanni; Andrighetto, Alberto

2010-11-01

In a facility for the production of radioactive ion beams (RIBs), the target system and the ion source are the most critical objects. In the context of the Selective Production of Exotic Species (SPES) project, a proton beam directly impinges a Uranium Carbide production target, generating approximately 10 13 fissions per second. The radioactive isotopes produced by the 238U fissions are then directed to the ion source to acquire a charge state. After that, the radioactive ions obtained are transported electrostatically to the subsequent areas of the facility. In this work the surface ion source at present adopted for the SPES project is studied by means of both analytical and numerical thermal-electric models. The theoretical results are compared with temperature and electric potential difference measurements.

The calibration of the intramolecular nitrogen isotope distribution in nitrous oxide measured by isotope ratio mass spectrometry.

PubMed

Westley, Marian B; Popp, Brian N; Rust, Terri M

2007-01-01

Two alternative approaches for the calibration of the intramolecular nitrogen isotope distribution in nitrous oxide using isotope ratio mass spectrometry have yielded a difference in the 15N site preference (defined as the difference between the delta15N of the central and end position nitrogen in NNO) of tropospheric N2O of almost 30 per thousand. One approach is based on adding small amounts of labeled 15N2O to the N2O reference gas and tracking the subsequent changes in m/z 30, 31, 44, 45 and 46, and this yields a 15N site preference of 46.3 +/- 1.4 per thousand for tropospheric N2O. The other involves the synthesis of N2O by thermal decomposition of isotopically characterized ammonium nitrate and yields a 15N site preference of 18.7 +/- 2.2 per thousand for tropospheric N2O. Both approaches neglect to fully account for isotope effects associated with the formation of NO+ fragment ions from the different isotopic species of N2O in the ion source of a mass spectrometer. These effects vary with conditions in the ion source and make it impossible to reproduce a calibration based on the addition of isotopically enriched N2O on mass spectrometers with different ion source configurations. These effects have a much smaller impact on the comparison of a laboratory reference gas with N2O synthesized from isotopically characterized ammonium nitrate. This second approach was successfully replicated and leads us to advocate the acceptance of the site preference value 18.7 +/- 2.2 per thousand for tropospheric N2O as the provisional community standard until further independent calibrations are developed and validated. We present a technique for evaluating the isotope effects associated with fragment ion formation and revised equations for converting ion signal ratios into isotopomer ratios. Copyright 2007 John Wiley & Sons, Ltd.

Note: Ion source design for ion trap systems

NASA Astrophysics Data System (ADS)

Noriega, J. R.; Quevedo, M.; Gnade, B.; Vasselli, J.

2013-06-01

A small plasma (glow discharge) based ion source and circuit are described in this work. The ion source works by producing a high voltage pulsed discharge between two electrodes in a pressure range of 50-100 mTorr. A third mesh electrode is used for ion extraction. The electrodes are small stainless steel screws mounted in a MACOR ionization chamber in a linear arrangement. The electrode arrangement is driven by a circuit, design for low power operation. This design is a proof of concept intended for applications on small cylindrical ion traps.

Brightness measurement of an electron impact gas ion source for proton beam writing applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, N.; Santhana Raman, P.; Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583

We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness thatmore » is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.« less

Brightness measurement of an electron impact gas ion source for proton beam writing applications.

PubMed

Liu, N; Xu, X; Pang, R; Raman, P Santhana; Khursheed, A; van Kan, J A

2016-02-01

We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

Electron string phenomenon: physics and use

NASA Astrophysics Data System (ADS)

Donets, Evgeny D.

2004-01-01

Electron string phenomenon arises as a result of phase transition of a state of multiply reflected electron beam to this new discovered state of one component electron plasma and can be easily observed in the reflex mode of EBIS operation. The transition goes via a strong instability, which causes considerable electron energy spread, which in its turn suppresses the instability. Electron string state is a stationary state of hot pure electron plasma, which is heated by injected electron beam and cooled because of electron loses. Electron string is quiet in broad regions of experimental parameters, so that it is used for confinement and ionization of positive ions by electron impact to highly charge states similar to electron beams in EBIS. Application of electron strings instead of electron beams for ion production allows to save about 99% of electric power of electron beam and simultaneously to improve reliability of an ion source considerably. The JINR EBIS `Krion-2' in the string mode of operation is used for production of N7+, Ar16+ and Fe24+ ion beams and their acceleration to relativistic energies on the facility of the JINR super conducting one turn injection synchrotron `Nuklotron'. The tubular electron string possibly can exist and it is under study now theoretically and experiments are prepared now. Estimations show that a Tubular Electron String Ion Source (TESIS) could have up to three orders of magnitude higher ion output then a Linear one (LESIS). In frames of nuclear astrophysics electron strings can be used for research of fusion nuclear reactions at low energies in conditions when both beam and target nuclei do not carry orbital electrons. The project NARITA — Nuclear Astrophysics Researches in an Ion Trap Apparatus is proposed. Polarization effects also can be studied.

Negative hydrogen ion sources for accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moehs, D.P.; /Fermilab; Peters, J.

2005-08-01

A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systemsmore » to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.« less

Microwave ion source

DOEpatents

Leung, Ka-Ngo; Reijonen, Jani; Thomae, Rainer W.

2005-07-26

A compact microwave ion source has a permanent magnet dipole field, a microwave launcher, and an extractor parallel to the source axis. The dipole field is in the form of a ring. The microwaves are launched from the middle of the dipole ring using a coaxial waveguide. Electrons are heated using ECR in the magnetic field. The ions are extracted from the side of the source from the middle of the dipole perpendicular to the source axis. The plasma density can be increased by boosting the microwave ion source by the addition of an RF antenna. Higher charge states can be achieved by increasing the microwave frequency. A xenon source with a magnetic pinch can be used to produce intense EUV radiation.

Beam Profile Studies for a One Eighth Betatron Wavelength Final Focusing Cell Following Phase Mixed Transport

DTIC Science & Technology

1988-10-26

concentrated into this off- axis peak is then considered. Estimates of the source brightness ( extraction ion diode source current density divided by the square...radioactive contamination of the accelerator. One possible scheme for avoiding this problem is to use extraction geometry ion diodes to focus the ion beams...annular region. These results will be coupled to two simple models of extraction ion diodes to determihe the ion source brightness requirements. These

Cleaning techniques for intense ion beam sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menge, P.R.; Cuneo, M.E.; Bailey, J.E.

Generation of high power lithium ion beams on the SABRE (1TW) and PBFA-X (20 TW) accelerators have been limited by the parallel acceleration of contaminant ions. during the beam pulse lithium is replaced by protons and carbon ions. This replacement is accompanied by rapid impedance decay of the diode. The contaminant hydrogen and carbon is believed to originate from impurity molecules on the surface and in the bulk of the lithium ion source and its substrate material. Cleaning techniques designed to remove hydrocarbons from the ion source have been employed with some success in test stand experiments and on SABRE.more » The test stand experiments have shown that a lithium fluoride (LiF) ion source film can accrue dozens of hydrocarbon monolayers on its surface while sitting in vacuum. Application of 13.5 MHz RF discharge cleaning with 90% Ar/10% O{sub 2} can significantly reduce the surface hydrocarbon layers on the LiF film. On SABRE, combinations of RF discharge cleaning, anode heating, layering gold between the source film (LiF) and its substrate, and cryogenic cathode cooling produced an increase by a factor of 1.5--2 in the quantity of high energy lithium in the ion beam. A corresponding decrease in protons and carbon ions was also observed. Cleaning experiments on PBFA-X are underway. New designs of contamination resistant films and Li ion sources are currently being investigated.« less

Improvements for extending the time between maintenance periods for the Heidelberg ion beam therapy center (HIT) ion sources.

PubMed

Winkelmann, Tim; Cee, Rainer; Haberer, Thomas; Naas, Bernd; Peters, Andreas; Schreiner, Jochen

2014-02-01

The clinical operation at the Heidelberg Ion Beam Therapy Center (HIT) started in November 2009; since then more than 1600 patients have been treated. In a 24/7 operation scheme two 14.5 GHz electron cyclotron resonance ion sources are routinely used to produce protons and carbon ions. The modification of the low energy beam transport line and the integration of a third ion source into the therapy facility will be shown. In the last year we implemented a new extraction system at all three sources to enhance the lifetime of extraction parts and reduce preventive and corrective maintenance. The new four-electrode-design provides electron suppression as well as lower beam emittance. Unwanted beam sputtering effects which typically lead to contamination of the insulator ceramics and subsequent high-voltage break-downs are minimized by the beam guidance of the new extraction system. By this measure the service interval can be increased significantly. As a side effect, the beam emittance can be reduced allowing a less challenging working point for the ion sources without reducing the effective beam performance. This paper gives also an outlook to further enhancements at the HIT ion source testbench.

VUV spectroscopic observations on the SABRE applied-B ion diode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Filuk, A.B.; Nash, T.J.; Noack, D.D.

We are using VUV spectroscopy to study the ion source region on the SABRE applied-B extraction ion diode. The VUV diagnostic views the anode-cathode gap perpendicular to the ion acceleration direction, and images a region 0--1 mm from the anode onto the entrance slit of a I m normal-incidence spectrometer. Time resolution is obtained by gating multiple striplines of a CuI- or MgF{sub 2} -coated micro-channel plate intensifier. We report on results with a passive proton/carbon ion source. Lines of carbon and oxygen are observed over 900--1600 {angstrom}. The optical depths of most of the lines are less than ormore » of order 1. Unfolding the Doppler broadening of the ion lines in the source plasma, we calculate the contribution of the source to the accelerated C IV ion micro-divergence as 4 mrad at peak power. Collisional-radiative modeling of oxygen line intensities provides the source plasma average electron density of 7{times}10{sup 16} cm{sup {minus}3} and temperature of 10 eV Measurements are planned with a lithium ion source and with VUV absorption spectroscopy.« less

First-principles study of amorphous carbon: a promising candidate for Na-ion batteries

NASA Astrophysics Data System (ADS)

Kotsis, Konstantinos; Legrain, Fleur; Manzhos, Sergei

2015-03-01

The perspective of a widespread use of clean but intermittent sources of electricity (wind and solar) as well as that of hybrid electric vehicles calls for alternatives to Li-ion batteries as Li resources are limited. Na being abundant, cheap, and a relatively light and small atom, Na-ion batteries have attracted a lot of interest the past few years. However, while most of the Na-ion batteries studies focus on the positive electrode, the negative electrode remains little investigated and an efficient anode providing all a good capacity, a high cycle life, and a descent rate of charge/discharge, is still not available. The efficient electrode materials for Li, in particular diamond Si and graphite C, have been shown to not allow the intercalation of Na [1, 2]. Computational studies report positive intercalation energies [3, 4] and therefore suggest that the insertion of Na into the crystalline framework (C and Si) is thermodynamically not favored: Na atoms prefer to gather into Na clusters rather than to intercalate into the crystalline phase. Amorphization of Si was found to be a valid strategy to improve the interaction between Si and Na [3]. We investigate here the effects of amorphization of C on its storage properties vis-à-vis Na (as well as Li for reference).

Ultrasensitive Ambient Mass Spectrometric Analysis with a Pin-to-Capillary Flowing Atmospheric-Pressure Afterglow Source

PubMed Central

Shelley, Jacob T.; Wiley, Joshua S.; Hieftje, Gary M.

2011-01-01

The advent of ambient desorption/ionization mass spectrometry has resulted in a strong interest in ionization sources that are capable of direct analyte sampling and ionization. One source that has enjoyed increasing interest is the Flowing Atmospheric-Pressure Afterglow (FAPA). FAPA has been proven capable of directly desorbing/ionizing samples in any phase (solid, liquid, or gas) and with impressive limits of detection (<100 fmol). The FAPA was also shown to be less affected by competitive-ionization matrix effects than other plasma-based sources. However, the original FAPA design exhibited substantial background levels, cluttered background spectra in the negative-ion mode, and significant oxidation of aromatic analytes, which ultimately compromised analyte identification and quantification. In the present study, a change in the FAPA configuration from a pin-to-plate to a pin-to-capillary geometry was found to vastly improve performance. Background signals in positive- and negative-ionization modes were reduced by 89% and 99%, respectively. Additionally, the capillary anode strongly reduced the amount of atomic oxygen that could cause oxidation of analytes. Temperatures of the gas stream that interacts with the sample, which heavily influences desorption capabilities, were compared between the two sources by means of IR thermography. The performance of the new FAPA configuration is evaluated through the determination of a variety of compounds in positive- and negative-ion mode, including agrochemicals and explosives. A detection limit of 4 amol was found for the direct determination of the agrochemical ametryn, and appears to be spectrometer-limited. The ability to quickly screen for analytes in bulk liquid samples with the pin-to-capillary FAPA is also shown. PMID:21627097

Ultrasensitive ambient mass spectrometric analysis with a pin-to-capillary flowing atmospheric-pressure afterglow source.

PubMed

Shelley, Jacob T; Wiley, Joshua S; Hieftje, Gary M

2011-07-15

The advent of ambient desorption/ionization mass spectrometry has resulted in a strong interest in ionization sources that are capable of direct analyte sampling and ionization. One source that has enjoyed increasing interest is the flowing atmospheric-pressure afterglow (FAPA). The FAPA has been proven capable of directly desorbing/ionizing samples in any phase (solid, liquid, or gas) and with impressive limits of detection (<100 fmol). The FAPA was also shown to be less affected by competitive-ionization matrix effects than other plasma-based sources. However, the original FAPA design exhibited substantial background levels, cluttered background spectra in the negative-ion mode, and significant oxidation of aromatic analytes, which ultimately compromised analyte identification and quantification. In the present study, a change in the FAPA configuration from a pin-to-plate to a pin-to-capillary geometry was found to vastly improve performance. Background signals in positive- and negative-ionization modes were reduced by 89% and 99%, respectively. Additionally, the capillary anode strongly reduced the amount of atomic oxygen that could cause oxidation of analytes. Temperatures of the gas stream that interacts with the sample, which heavily influences desorption capabilities, were compared between the two sources by means of IR thermography. The performance of the new FAPA configuration is evaluated through the determination of a variety of compounds in positive- and negative-ion mode, including agrochemicals and explosives. A detection limit of 4 amol was found for the direct determination of the agrochemical ametryn and appears to be spectrometer-limited. The ability to quickly screen for analytes in bulk liquid samples with the pin-to-capillary FAPA is also shown.

The selective and efficient laser ion source and trap project LIST for on-line production of exotic nuclides

NASA Astrophysics Data System (ADS)

Wendt, Klaus; Gottwald, Tina; Hanstorp, Dag; Mattolat, Christoph; Raeder, Sebastian; Rothe, Sebastian; Schwellnus, Fabio; Havener, Charles; Lassen, Jens; Liu, Yuan

2010-02-01

Laser ion sources based on resonant excitation and ionization of atoms are well-established tools for selective and efficient production of radioactive ion beams. A recent trend is the complementary installation of reliable state-of-the-art all solid-state Ti:Sapphire laser systems. To date, 35 elements of the Periodic Table are available at laser ion sources by using these novel laser systems, which complements the overall accessibility to 54 elements including use of traditional dye lasers. Recent progress in the field concerns the identification of suitable optical excitation schemes for Ti:Sapphire laser excitation as well as technical developments of the source in respect to geometry, cavity material as well as by incorporation of an ion guide system in the form of the laser ion source trap LIST.

New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited).

PubMed

Zhao, H Y; Zhang, J J; Jin, Q Y; Liu, W; Wang, G C; Sun, L T; Zhang, X Z; Zhao, H W

2016-02-01

A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production of highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10(13) W cm(-2) in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.

New development of laser ion source for highly charged ion beam production at Institute of Modern Physics (invited)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Jin, Q. Y.

2016-02-15

A laser ion source based on Nd:YAG laser has been being studied at the Institute of Modern Physics for the production of high intensity high charge state heavy ion beams in the past ten years, for possible applications both in a future accelerator complex and in heavy ion cancer therapy facilities. Based on the previous results for the production of multiple-charged ions from a wide range of heavy elements with a 3 J/8 ns Nd:YAG laser [Zhao et al., Rev. Sci. Instrum. 85, 02B910 (2014)], higher laser energy and intensity in the focal spot are necessary for the production ofmore » highly charged ions from the elements heavier than aluminum. Therefore, the laser ion source was upgraded with a new Nd:YAG laser, the maximum energy of which is 8 J and the pulse duration can be adjusted from 8 to 18 ns. Since then, the charge state distributions of ions from various elements generated by the 8 J Nd:YAG laser were investigated for different experimental conditions, such as laser energy, pulse duration, power density in the focal spot, and incidence angle. It was shown that the incidence angle is one of the most important parameters for the production of highly charged ions. The capability of producing highly charged ions from the elements lighter than silver was demonstrated with the incidence angle of 10° and laser power density of 8 × 10{sup 13} W cm{sup −2} in the focal spot, which makes a laser ion source complementary to the superconducting electron cyclotron resonance ion source for the future accelerator complex especially in terms of the ion beam production from some refractory elements. Nevertheless, great efforts with regard to the extraction of intense ion beams, modification of the ion beam pulse duration, and reliability of the ion source still need to be made for practical applications.« less

Dense plasma focus (DPF) accelerated non radio isotopic radiological source

DOEpatents

Rusnak, Brian; Tang, Vincent

2017-01-31

A non-radio-isotopic radiological source using a dense plasma focus (DPF) to produce an intense z-pinch plasma from a gas, such as helium, and which accelerates charged particles, such as generated from the gas or injected from an external source, into a target positioned along an acceleration axis and of a type known to emit ionizing radiation when impinged by the type of accelerated charged particles. In a preferred embodiment, helium gas is used to produce a DPF-accelerated He2+ ion beam to a beryllium target, to produce neutron emission having a similar energy spectrum as a radio-isotopic AmBe neutron source. Furthermore, multiple DPFs may be stacked to provide staged acceleration of charged particles for enhancing energy, tunability, and control of the source.

Electron energy recovery system for negative ion sources

DOEpatents

Dagenhart, W.K.; Stirling, W.L.

1979-10-25

An electron energy recovery system for negative ion sources is provided. The system, employing crossed electric and magnetic fields, separates the electrons from the ions as they are extracted from the ion source plasma generator and before the ions are accelerated to their full energy. With the electric and magnetic fields oriented 90/sup 0/ to each other, the electrons remain at approximately the electrical potential at which they were generated. The electromagnetic forces cause the ions to be accelerated to the full accelerating supply voltage energy while being deflected through an angle of less than 90/sup 0/. The electrons precess out of the accelerating field region into an electron recovery region where they are collected at a small fraction of the full accelerating supply energy. It is possible, by this method, to collect > 90% of the electrons extracted along with the negative ions from a negative ion source beam at < 4% of full energy.

Caesium sputter ion source compatible with commercial SIMS instruments

NASA Astrophysics Data System (ADS)

Belykh, S. F.; Palitsin, V. V.; Veryovkin, I. V.; Kovarsky, A. P.; Chang, R. J. H.; Adriaens, A.; Dowsett, M.; Adams, F.

2006-07-01

A simple design for a caesium sputter cluster ion source compatible with commercially available secondary ion mass spectrometers is reported. This source has been tested with the Cameca IMS 4f instrument using the cluster Si n- and Cu n- ions, and will shortly be retrofitted to the floating low energy ion gun (FLIG) of the type used on the Cameca 4500/4550 quadruple instruments. Our experiments with surface characterization and depth profiling conducted to date demonstrate improvements of analytical capabilities of the SIMS instrument due to the non-additive enhancement of secondary ion emission and shorter ion ranges of polyatomic projectiles compared to atomic ions with the same impact energy.

Development of high intensity ion sources for a Tandem-Electrostatic-Quadrupole facility for Accelerator-Based Boron Neutron Capture Therapy.

PubMed

Bergueiro, J; Igarzabal, M; Sandin, J C Suarez; Somacal, H R; Vento, V Thatar; Huck, H; Valda, A A; Repetto, M; Kreiner, A J

2011-12-01

Several ion sources have been developed and an ion source test stand has been mounted for the first stage of a Tandem-Electrostatic-Quadrupole facility For Accelerator-Based Boron Neutron Capture Therapy. A first source, designed, fabricated and tested is a dual chamber, filament driven and magnetically compressed volume plasma proton ion source. A 4 mA beam has been accelerated and transported into the suppressed Faraday cup. Extensive simulations of the sources have been performed using both 2D and 3D self-consistent codes. Copyright © 2011 Elsevier Ltd. All rights reserved.

HIGH VOLTAGE ION SOURCE

DOEpatents

Luce, J.S.

1960-04-19

A device is described for providing a source of molecular ions having a large output current and with an accelerated energy of the order of 600 kv. Ions are produced in an ion source which is provided with a water-cooled source grid of metal to effect maximum recombination of atomic ions to molecular ions. A very high accelerating voltage is applied to withdraw and accelerate the molecular ions from the source, and means are provided for dumping the excess electrons at the lowest possible potentials. An accelerating grid is placed adjacent to the source grid and a slotted, grounded accelerating electrode is placed adjacent to the accelerating grid. A potential of about 35 kv is maintained between the source grid and accelerating grid, and a potential of about 600 kv is maintained between the accelerating grid and accelerating electrode. In order to keep at a minimum the large number of oscillating electrons which are created when such high voltages are employed in the vicinity of a strong magnetic field, a plurality of high voltage cascaded shields are employed with a conventional electron dumping system being employed between each shield so as to dump the electrons at the lowest possible potential rather than at 600 kv.

Development of the Long Pulse Negative Ion Source for ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemsworth, R.S.; Svensson, L.; Esch, H.P.L. de

2005-04-06

A model of the ion source designed for the neutral beam injectors of the International Thermonuclear Experimental Reactor (ITER), the KAMABOKO III ion source, is being tested on the MANTIS test stand at the DRFC Cadarache in collaboration with JAERI, Japan, who designed and supplied the ion source. The ion source is attached to a 3 grid 30 keV accelerator (also supplied by JAERI) and the accelerated negative ion current is determined from the energy deposited on a calorimeter located 1.6 m from the source.During experiments on MANTIS three adverse effects of long pulse operation were found: The negative ionmore » current to the calorimeter is {approx_equal}50% of that obtained from short pulse operation Increasing the plasma grid (PG) temperature results in {<=}40% enhancement in negative ion yield, substantially below that reported for short pulse operation, {>=}100%. The caesium 'consumption' is up to 1500 times that expected.Results presented here indicate that each of these is, at least partially, explained by thermal effects. Additionally presented are the results of a detailed characterisation of the source, which enable the most efficient mode of operation to be identified.« less

First operation and effect of a new tandem-type ion source based on electron cyclotron resonance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, Yushi, E-mail: kato@eei.eng.osaka-u.ac.jp; Kimura, Daiju; Yano, Keisuke

A new tandem type source has been constructed on the basis of electron cyclotron resonance plasma for producing synthesized ion beams in Osaka University. Magnetic field in the first stage consists of all permanent magnets, i.e., cylindrically comb shaped one, and that of the second stage consists of a pair of mirror coil, a supplemental coil and the octupole magnets. Both stage plasmas can be individually operated, and produced ions in which is energy controlled by large bore extractor also can be transported from the first to the second stage. We investigate the basic operation and effects of the tandemmore » type electron cyclotron resonance ion source (ECRIS). Analysis of ion beams and investigation of plasma parameters are conducted on produced plasmas in dual plasmas operation as well as each single operation. We describe construction and initial experimental results of the new tandem type ion source based on ECRIS with wide operation window for aiming at producing synthesized ion beams as this new source can be a universal source in future.« less

High voltage holding in the negative ion sources with cesium deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belchenko, Yu.; Abdrashitov, G.; Ivanov, A.

High voltage holding of the large surface-plasma negative ion source with cesium deposition was studied. It was found that heating of ion-optical system electrodes to temperature >100 °C facilitates the source conditioning by high voltage pulses in vacuum and by beam shots. The procedure of electrode conditioning and the data on high-voltage holding in the negative ion source with small cesium seed are described. The mechanism of high voltage holding improvement by depletion of cesium coverage is discussed.

A practical approach to reduce interference due to in-source collision-induced dissociation of acylglucuronides in LC-MS/MS.

PubMed

Mess, Jean-Nicholas; Bérubé, Eugénie-Raphaelle; Furtado, Milton; Garofolo, Fabio

2011-08-01

In LC-MS/MS, glucuronide conjugated metabolites may convert back to the parent drug due to in-source collision-induced dissociation (CID). During the bioanalysis of naproxen, it was noticed that naproxen acylglucuronide exhibited intense in-source CID to the naproxen [M+H](+) ion under positive ESI. However, no in-source CID of the acylglucuronide to the naproxen [M+NH(4)](+) adduct was observed. Furthermore, absolutely no in-source CID was detected under negative ESI. This phenomenon was not only observed for naproxen acylglucuronide but for eight other acylglucuronides compounds. We have shown that monitoring the parent drug [M-H](-) or [M+NH(4)](+) whenever possible could be an easy approach used by bioanalytical scientists to minimize the impact of in-source CID of acylglucuronides to the parent drug.

The study towards high intensity high charge state laser ion sources.

PubMed

Zhao, H Y; Jin, Q Y; Sha, S; Zhang, J J; Li, Z M; Liu, W; Sun, L T; Zhang, X Z; Zhao, H W

2014-02-01

As one of the candidate ion sources for a planned project, the High Intensity heavy-ion Accelerator Facility, a laser ion source has been being intensively studied at the Institute of Modern Physics in the past two years. The charge state distributions of ions produced by irradiating a pulsed 3 J/8 ns Nd:YAG laser on solid targets of a wide range of elements (C, Al, Ti, Ni, Ag, Ta, and Pb) were measured with an electrostatic ion analyzer spectrometer, which indicates that highly charged ions could be generated from low-to-medium mass elements with the present laser system, while the charge state distributions for high mass elements were relatively low. The shot-to-shot stability of ion pulses was monitored with a Faraday cup for carbon target. The fluctuations within ±2.5% for the peak current and total charge and ±6% for pulse duration were demonstrated with the present setup of the laser ion source, the suppression of which is still possible.

Simultaneous measurements of work function and H‒ density including caesiation of a converter surface

NASA Astrophysics Data System (ADS)

Cristofaro, S.; Friedl, R.; Fantz, U.

2017-08-01

Negative hydrogen ion sources rely on the surface conversion of neutral atomic hydrogen and positive hydrogen ions to H-. The efficiency of this process depends on the actual work function of the converter surface. By introducing caesium into the source the work function decreases, enhancing the negative ion yield. In order to study the impact of the work function on the H- surface production at similar conditions to the ones in ion sources for fusion devices like ITER and DEMO, fundamental investigations are performed in a flexible laboratory experiment. The work function of the converter surface can be absolutely measured by photoelectric effect, while a newly installed cavity ring-down spectroscopy system (CRDS) measures the H- density. The CRDS is firstly tested and characterized by investigations on H- volume production. Caesiation of a stainless steel sample is then performed in vacuum and the plasma effect on the Cs layer is investigated also for long plasma-on times. A minimum work function of (1.9±0.1) eV is reached after some minutes of plasma treatment, resulting in a reduction by a value of 0.8 eV compared to vacuum measurements. The H- density above the surface is (2.1±0.5)×1015 m-3. With further plasma exposure of the caesiated surface, the work function increases up to 3.75 eV, due to the impinging plasma particles which gradually remove the Cs layer. As a result, the H- density decreases by a factor of at least 2.

The use of isoprene as a novel dopant in negative ion atmospheric pressure photoionization mass spectrometry coupled to high-performance liquid chromatography.

PubMed

Dousty, Faezeh; O'Brien, Rob

2015-06-15

As in the case with positive ion atmospheric pressure photoionization (PI-APPI), the addition of dopants significantly improves the sensitivity of negative ion APPI (NI-APPI). However, the research on dopant-assisted-NI-APPI has been quite limited compared to the studies on dopant-assisted PI-APPI. This work presents the potential of isoprene as a novel dopant for NI-APPI. Thirteen compounds, possessing suitable gas-phase ion energetic properties in order to make stable negative ions, were selected. Dopants were continuously introduced into a tee junction prior to the ion source through a fused-silica capillary, while analytes were directly injected into the same tee. Then both were mixed with the continuous solvent from high-performance liquid chromatography (HPLC), nebulized, and entered the source. The nebulized stream was analyzed by APPI tandem quadrupole mass spectrometry in the negative ion mode. The results obtained using isoprene were compared with those obtained by using toluene as a dopant and dopant-free NI-APPI. Isoprene enhanced the ionization intensities of the studied compounds, which were found to be comparable and, in some cases, more effective than toluene. The mechanisms leading to the observed set of negative analyte ions were also discussed. Because in NI-APPI, thermal electrons, which are produced during the photoionization of a dopant, are considered the main reagent ions, both isoprene and toluene promoted the ionization of analytes through the same mechanisms, as expected. Isoprene was shown to perform well as a novel dopant for NI-APPI. Isoprene has a high photoabsorption cross section in the VUV region; therefore, its photoionization leads to a highly effective production of thermal electrons, which further promotes the ionization of analytes. In addition, isoprene is environmentally benign and less toxic compared to currently used dopants. Copyright © 2015 John Wiley & Sons, Ltd.

A 60 mA DC H- multi cusp ion source developed at TRIUMF

NASA Astrophysics Data System (ADS)

Jayamanna, K.; Ames, F.; Bylinskii, I.; Lovera, M.; Minato, B.

2018-07-01

This paper describes the latest high-current multi cusp type ion source developed at TRIUMF, which is capable of producing a negative hydrogen ion beam (H-) of 60 mA of direct current at 140V and 90A arc. The results achieved to date including emittance measurements and filament lifetime issues are presented. The low current version of this ion source is suitable for medical cyclotrons as well as accelerators and the high current version is intended for producing large neutral hydrogen beams for fusion research. The description of the source magnetic configuration, the electron filter profile and the differential pumping techniques given in the paper will allow the building of an arc discharge H- ion source with similar properties.

Very Large Area/Volume Microwave ECR Plasma and Ion Source

NASA Technical Reports Server (NTRS)

Foster, John E. (Inventor); Patterson, Michael J. (Inventor)

2009-01-01

The present invention is an apparatus and method for producing very large area and large volume plasmas. The invention utilizes electron cyclotron resonances in conjunction with permanent magnets to produce dense, uniform plasmas for long life ion thruster applications or for plasma processing applications such as etching, deposition, ion milling and ion implantation. The large area source is at least five times larger than the 12-inch wafers being processed to date. Its rectangular shape makes it easier to accommodate to materials processing than sources that are circular in shape. The source itself represents the largest ECR ion source built to date. It is electrodeless and does not utilize electromagnets to generate the ECR magnetic circuit, nor does it make use of windows.

Increasing positive ion number densities below the peak of ion-electron pair production in Titan's ionosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vigren, E.; Galand, M.; Shebanits, O.

2014-05-01

We combine derived ion-electron pair formation rates with Cassini Radio Plasma Wave Science Langmuir Probe measurements of electron and positive ion number densities in Titan's sunlit ionosphere. We show that positive ion number densities in Titan's sunlit ionosphere can increase toward significantly lower altitudes than the peak of ion-electron pair formation despite that the effective ion-electron recombination coefficient increases. This is explained by the increased mixing ratios of negative ions, which are formed by electron attachment to neutrals. While such a process acts as a sink for free electrons, the positive ions become longer-lived as the rate coefficients for ion-anionmore » neutralization reactions are smaller than those for ion-electron dissociative recombination reactions.« less

Ion current detector for high pressure ion sources for monitoring separations

DOEpatents

Smith, R.D.; Wahl, J.H.; Hofstadler, S.A.

1996-08-13

The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source. 7 figs.

Ion current detector for high pressure ion sources for monitoring separations

DOEpatents

Smith, Richard D.; Wahl, Jon H.; Hofstadler, Steven A.

1996-01-01

The present invention relates generally to any application involving the monitoring of signal arising from ions produced by electrospray or other high pressure (>100 torr) ion sources. The present invention relates specifically to an apparatus and method for the detection of ions emitted from a capillary electrophoresis (CE) system, liquid chromatography, or other small-scale separation methods. And further, the invention provides a very simple diagnostic as to the quality of the separation and the operation of an electrospray source.

Kinetic modeling of particle dynamics in H- negative ion sources (invited)

NASA Astrophysics Data System (ADS)

Hatayama, A.; Shibata, T.; Nishioka, S.; Ohta, M.; Yasumoto, M.; Nishida, K.; Yamamoto, T.; Miyamoto, K.; Fukano, A.; Mizuno, T.

2014-02-01

Progress in the kinetic modeling of particle dynamics in H- negative ion source plasmas and their comparisons with experiments are reviewed, and discussed with some new results. Main focus is placed on the following two topics, which are important for the research and development of large negative ion sources and high power H- ion beams: (i) Effects of non-equilibrium features of EEDF (electron energy distribution function) on H- production, and (ii) extraction physics of H- ions and beam optics.

Ion source design for industrial applications

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Robinson, R. S.

1981-01-01

The design of broad-beam industrial ion sources is described. The approach used emphasizes refractory metal cathodes and permanent-magnet multipole discharge chambers. Design procedures and sample calculations are given for the discharge chamber, ion optics, cathodes, and magnetic circuit. Hardware designs are included for the isolator, cathode supports, anode supports, pole-piece assembly, and ion-optics supports. There are other ways of designing most ion source components, but the designs presented are representative of current technology and adaptable to a wide range of configurations.

Development of the negative ion beams relevant to ITER and JT-60SA at Japan Atomic Energy Agency.

PubMed

Hanada, M; Kojima, A; Tobari, H; Nishikiori, R; Hiratsuka, J; Kashiwagi, M; Umeda, N; Yoshida, M; Ichikawa, M; Watanabe, K; Yamano, Y; Grisham, L R

2016-02-01

In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification. As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications.

Electrical shielding box measurement of the negative hydrogen beam from Penning ion gauge ion source.

PubMed

Wang, T; Yang, Z; Dong, P; long, J D; He, X Z; Wang, X; Zhang, K Z; Zhang, L W

2012-06-01

The cold-cathode Penning ion gauge (PIG) type ion source has been used for generation of negative hydrogen (H(-)) ions as the internal ion source of a compact cyclotron. A novel method called electrical shielding box dc beam measurement is described in this paper, and the beam intensity was measured under dc extraction inside an electrical shielding box. The results of the trajectory simulation and dc H(-) beam extraction measurement were presented. The effect of gas flow rate, magnetic field strength, arc current, and extraction voltage were also discussed. In conclusion, the dc H(-) beam current of about 4 mA from the PIG ion source with the puller voltage of 40 kV and arc current of 1.31 A was extrapolated from the measurement at low extraction dc voltages.

Status of ion sources at National Institute of Radiological Sciences.

PubMed

Kitagawa, A; Fujita, T; Goto, A; Hattori, T; Hamano, T; Hojo, S; Honma, T; Imaseki, H; Katagiri, K; Muramatsu, M; Sakamoto, Y; Sekiguchi, M; Suda, M; Sugiura, A; Suya, N

2012-02-01

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

Ring current dynamics and plasma sheet sources. [magnetic storms

NASA Technical Reports Server (NTRS)

Lyons, L. R.

1984-01-01

The source of the energized plasma that forms in geomagnetic storm ring currents, and ring current decay are discussed. The dominant loss processes for ring current ions are identified as charge exchange and resonant interactions with ion-cyclotron waves. Ring current ions are not dominated by protons. At L4 and energies below a few tens of keV, O+ is the most abundant ion, He+ is second, and protons are third. The plasma sheet contributes directly or indirectly to the ring current particle population. An important source of plasma sheet ions is earthward streaming ions on the outer boundary of the plasma sheet. Ion interactions with the current across the geomagnetic tail can account for the formation of this boundary layer. Electron interactions with the current sheet are possibly an important source of plasma sheet electrons.

Status of ion sources at National Institute of Radiological Sciencesa)

NASA Astrophysics Data System (ADS)

Kitagawa, A.; Fujita, T.; Goto, A.; Hattori, T.; Hamano, T.; Hojo, S.; Honma, T.; Imaseki, H.; Katagiri, K.; Muramatsu, M.; Sakamoto, Y.; Sekiguchi, M.; Suda, M.; Sugiura, A.; Suya, N.

2012-02-01

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

Ion Outflow Observations

NASA Technical Reports Server (NTRS)

Mellot, Mary (Technical Monitor)

2002-01-01

The characteristics of out-flowing ions have been investigated under various circumstances. In particular the upwelling of ions from the cleft region has been studied to attempt to look at source characteristics (e.g., temperature, altitude). High altitude (6-8 Re) data tend to show ions species that have the same velocity and are adiabatically cooled. Such ions, while representative of their source, can not provide an accurate picture. Ion observations from the TIDE detector on the Polar spacecraft show an energy (or equivalently a velocity) spectrum of ions as they undo the geomagnetic mass spectrometer effect due to convection-gravity separation of the different species. Consolidation of this type of data into a complete representation of the source spectrum can be attempted by building a set of maximum-phase-space- density-velocity pairs and attributing the total to the source.

Super-atmospheric pressure chemical ionization mass spectrometry.

PubMed

Chen, Lee Chuin; Rahman, Md Matiur; Hiraoka, Kenzo

2013-03-01

Super-atmospheric pressure chemical ionization (APCI) mass spectrometry was performed using a commercial mass spectrometer by pressurizing the ion source with compressed air up to 7 atm. Similar to typical APCI source, reactant ions in the experiment were generated with corona discharge using a needle electrode. Although a higher needle potential was necessary to initiate the corona discharge, discharge current and detected ion signal were stable at all tested pressures. A Roots booster pump with variable pumping speed was installed between the evacuation port of the mass spectrometer and the original rough pumps to maintain a same pressure in the first pumping stage of the mass spectrometer regardless of ion source pressure. Measurement of gaseous methamphetamine and research department explosive showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. Beyond 5 atm, the ion intensity decreased with further increase of pressure, likely due to greater ion losses inside the ion transport capillary. For benzene, it was found that besides molecular ion and protonated species, ion due to [M + 2H](+) which was not so common in APCI, was also observed with high ion abundance under super-atmospheric pressure condition. Copyright © 2013 John Wiley & Sons, Ltd.

H- ion sources for CERN's Linac4

NASA Astrophysics Data System (ADS)

Lettry, J.; Aguglia, D.; Coutron, Y.; Chaudet, E.; Dallocchio, A.; Gil Flores, J.; Hansen, J.; Mahner, E.; Mathot, S.; Mattei, S.; Midttun, O.; Moyret, P.; Nisbet, D.; O'Neil, M.; Paoluzzi, M.; Pasquino, C.; Pereira, H.; Arias, J. Sanchez; Schmitzer, C.; Scrivens, R.; Steyaert, D.

2013-02-01

The specifications set to the Linac4 ion source are: H- ion pulses of 0.5 ms duration, 80 mA intensity and 45 keV energy within a normalized emittance of 0.25 mmmrad RMS at a repetition rate of 2 Hz. In 2010, during the commissioning of a prototype based on H- production from the plasma volume, it was observed that the powerful co-extracted electron beam inherent to this type of ion source could destroy its electron beam dump well before reaching nominal parameters. However, the same source was able to provide 80 mA of protons mixed with a small fraction of H2+ and H3+ molecular ions. The commissioning of the radio frequency quadrupole accelerator (RFQ), beam chopper and H- beam diagnostics of the Linac4 are scheduled for 2012 and its final installation in the underground building is to start in 2013. Therefore, a crash program was launched in 2010 and reviewed in 2011 aiming at keeping the original Linac4 schedule with the following deliverables: Design and production of a volume ion source prototype suitable for 20-30 mA H- and 80 mA proton pulses at 45 keV by mid-2012. This first prototype will be dedicated to the commissioning of the low energy components of the Linac4. Design and production of a second prototype suitable for 40-50 mA H- based on an external RF solenoid plasma heating and cesiated-surface production mechanism in 2013 and a third prototype based on BNL's Magnetron aiming at reliable 2 Hz and 80 mA H- operations in 2014. In order to ease the future maintenance and allow operation with Ion sources based on three different production principles, an ion source "front end" providing alignment features, pulsed gas injection, pumping units, beam tuning capabilities and pulsed bipolar high voltage acceleration was designed and is being produced. This paper describes the progress of the Linac4 ion source program, the design of the Front end and first ion source prototype. Preliminary results of the summer 2012 commissioning are presented. The outlook on the future prototype ion sources is sketched.

Development and Evaluation of an Externally Air-Cooled Low-Flow torch and the Attenuation of Space Charge and Matrix Effects in Inductively Coupled Plasma Mass Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Praphairaksit, Narong

2000-09-12

An externally air-cooled low-flow torch has been constructed and successfully demonstrated for applications in inductively coupled plasma mass spectrometry (ICP-MS). The torch is cooled by pressurized air flowing at ~70 L/min through a quartz air jacket onto the exterior of the outer tube. The outer gas flow rate and operating RF forward power are reduced considerably. Although plasmas can be sustained at the operating power as low as 400 W with a 2 L/min of outer gas flow, somewhat higher power and outer gas flows are advisable. A stable and analytical useful plasma can be obtained at 850 W withmore » an outer gas flow rate of ~4 L/min. Under these conditions, the air-cooled plasma produces comparable sensitivities, doubly charged ion ratios, matrix effects and other analytical merits as those produced by a conventional torch while using significantly less argon and power requirements. Metal oxide ion ratios are slightly higher with the air-cooled plasma but can be mitigated by reducing the aerosol gas flow rate slightly with only minor sacrifice in analyte sensitivity. A methodology to alleviate the space charge and matrix effects in ICP-MS has been developed. A supplemental electron source adapted from a conventional electron impact ionizer is added to the base of the skimmer. Electrons supplied from this source downstream of the skimmer with suitable amount and energy can neutralize the positive ions in the beam extracted from the plasma and diminish the space charge repulsion between them. As a result, the overall ion transmission efficiency and consequent analyte ion sensitivities are significantly improved while other important analytical aspects, such as metal oxide ion ratio, doubly charged ion ratio and background ions remain relatively unchanged with the operation of this electron source. This technique not only improves the ion transmission efficiency but also minimizes the matrix effects drastically. The matrix-induced suppression of signal for even the most troublesome combination of light analyte and heavy matrix elements can be attenuated from 90-99% to only 2-10% for 2 mM matrix solutions with an ultrasonic nebulizer. The supplemental electron current can be adjusted to ''titrate'' out the matrix effects as desired.« less

Comment on 'Effects of magnetic field gradient on ion beam current in cylindrical Hall ion source' [J. Appl. Phys. 102, 123305 (2007)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raitses, Y.; Smirnov, A.; Fisch, N. J.

It is argued that the key difference in the cylindrical Hall thruster (CHT) as compared to the end-Hall ion source cannot be exclusively attributed to the magnetic field topology [Tang et al., J. Appl. Phys. 102, 123305 (2007)]. With a similar mirror-type topology, the CHT configuration provides the electric field with nearly equipotential magnetic field surfaces and a better suppression of the electron cross-field transport, as compared to both the end-Hall ion source and the cylindrical Hall ion source of [Tang et al., J. Appl. Phys. 102, 123305 (2007)].

Recent developments of ion sources for life-science studies at the Heavy Ion Medical Accelerator in Chiba (invited)

NASA Astrophysics Data System (ADS)

Kitagawa, A.; Drentje, A. G.; Fujita, T.; Muramatsu, M.; Fukushima, K.; Shiraishi, N.; Suzuki, T.; Takahashi, K.; Takasugi, W.; Biri, S.; Rácz, R.; Kato, Y.; Uchida, T.; Yoshida, Y.

2016-02-01

With about 1000-h of relativistic high-energy ion beams provided by Heavy Ion Medical Accelerator in Chiba, about 70 users are performing various biology experiments every year. A rich variety of ion species from hydrogen to xenon ions with a dose rate of several Gy/min is available. Carbon, iron, silicon, helium, neon, argon, hydrogen, and oxygen ions were utilized between 2012 and 2014. Presently, three electron cyclotron resonance ion sources (ECRISs) and one Penning ion source are available. Especially, the two frequency heating techniques have improved the performance of an 18 GHz ECRIS. The results have satisfied most requirements for life-science studies. In addition, this improved performance has realized a feasible solution for similar biology experiments with a hospital-specified accelerator complex.