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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.

Cyclotrons are an important tool for accelerator sciences including the production of medical isotopes for imaging and therapy. For their successful and cost-efficient operation, the planned and unplanned down time of the cyclotron needs to be kept at a minimum without compromising reliability. One of the often required maintenance activities is the replacement of the filament in the ion source. Here, we are reporting on a new ion source filament tested on a medical cyclotron and its prolonging effect on the ion source operation.

TRIUMF has developed H− ion sources for decades and now they are being employed in TRIUMF cyclotrons as well as in various other machines. A high current version can produce up to 60 mA [1]. A medium range source is optimized to produce 20 mA. A new smaller H− ion source with a plasma volume of 50 mm x 75 mm ion source is being developed to produce 5 mA at a very low emittance and run years without changing the filament. Due to the low emittance and relatively little required maintenance, this ion source will suit cyclotrons as well as accelerators looking for reliable, stable operation with very low maintenance. Having four electrodes, this ion source can run at optimum extraction voltage while delivering the beam from 1 kV to 60 kV with little or no degradation of the beam quality. Performance of the source including beam current, arc parameters, emittance and filament lifetime are discussed in this paper.

The off-line ion source (OLIS) terminal provides beams from stable isotopes to ISAC (see Fig. 1) experiments as well as for accelerator commissioning and for pilot beams for radioactive beam experiments. The OLIS terminal (see Fig. 2) is equipped with a microwave driven cusp source for single and double charge ions, a surface ion source for low energy spread alkali beams, and a multi-charge ion source.

For the acceleration of radioactive isotopes with a mass greater than 30 amu charge breeding with an electron cyclotron resonance ion source (ECRIS) is being used at ISAC. Singly charged ions from the target ion source combination are injected into a 14.5 GHz ECRIS from PANTECHNIK and charge bred to highly charged ions with a mass to charge ratio around 6. Efficiencies from 1 to 8 % could be reached for different isotopes. The article describes the set- up of the system and reports on results obtained for efficiency as well as purity of the beam. Methods to improve the purity are discussed.

The feasibility of in-beam polarization of nuclear spin in F+ beams was studied. It was demonstrated that metastable atomic fluorine could be optically pumped on the closed transition (3s 4P5/2-3p 4D7/2) at 686 nm. The metastable production efficiency in sodium vapor was measured using optical depopulation pumping of the metastable on the (3s 4P5/2-3p 4D5/2) transition at 678 nm. At low helium density, 0.24 (+0.16/0.03) of the reionized beam was derived from metastables, implying an ion beam polarization of 24% would be feasible if the metastables were fully polarized. The hyperfine structures of the 3s 4P5/2, 3p 4D5/2 and 3p 4D7/2 states in 19F were measured via laser-induced fluorescence and modulated optical depopulation pumping. Based on these results, a scheme is suggested for polarizing 20F. Thesis work of Thomas E. Cocolios (M.Sc. 2005, McGill University, Montreal, QC) ispartof: Nuclear Instruments and Methods in Physics Research A vol:580 issue:3 pages:1571-1577 status: published

Nuclear reactions play a key role in understanding nucleosynthesis in stars. Recoil mass spectrometers such as DRAGON are well suited to study reactions with respect to astrophysical production because of direct detection of reaction products. Here we present the first stage of an experiment running at the recoil mass spectrometer DRAGON at the ISAC/TRIUMF facility in Vancouver, Canada, to study the reaction 40Ca(α, γ)44Ti at astrophysically relevant energies. This reaction is one of the key reactions for production of 44Ti, which has been identified in young supernova remnants by space based γ-ray telescopes onboard COMPTEL and INTEGRAL. In this paper we focus on technical upgrade of DRAGON for 40Ca(α, γ)44Ti and preliminary results at resonances at Ex ∼ 9.2 MeV.

A proof-of-principle approach for the production of intense (~108/s) radioactive ion beams, which differs from the standard ISOL (Isotope Separation On-Line) technique, has been demonstrated successfully using 11C at the TRIUMF laboratory. This approach uses 13 MeV protons produced by a medical cyclotron and should be useful for a range of radioisotopes of interest to the nuclear astrophysics research programme.PACS No.: 29.25.Rm

A polarizer beam line at the radioactive beams facility ISAC at TRIUMF is nearly complete. Initially for 8Li+ ions for β-NMR studies in condensed matter, it can in principle supply three or more experiments simultaneously, and the technique used is practicable with all alkali-metal ion beams. An atomic beam, created with over 90% efficiency by passing the initial unpolarized 30 keV beam through a sodium vapor jet target, will be polarized by colinear optical pumping. A novel feature is that the atomic beam is reionized with demonstrated high efficiency in a helium gas target. The emittance growth through the helium cell has been measured for stable 7Li+ beam on a test stand and found to be small. We report these measurements as a function of helium flow rates. A preliminary polarized 8Li+ run is planned for May, 2000.

Intense radioactive beams of 15 O are required in order to study the high temperatures of the CNO cycle via reactions on radioactive isotopes such as 15 O(α,γ) 19 Ne, which is a key breakout reaction for the rp-process in stars. We have proposed a target that will operate at 500 MeV and 100 μA proton beam by making use of the 16 O(p,pn) 15 O reaction. A water target 20 cm in length will generate approximately 18.5 TBq (500 Ci) of 15 O at equilibrium which is equivalent to 3×10 15 atoms of 15 O, of which 5–10% would be in the form of O 2 . One major advantage is that the target can operate at ambient temperatures.

The properties of ion sources and the beams extracted from them are critical to the successful design of the ISAC facility at TRIUMF. To better understand these properties, an off line 60 kV test stand has been constructed to test and evaluate targets and ion sources intended for use at the future ISAC facility. The test stand also presents the opportunity to evaluate diagnostics, beam monitoring and system control techniques required for ISAC. The test stand vacuum chamber mimics the ISAC target module. Ion beams are produced using a fixed geometry multielectrode extraction column and transported through 5m of beamline using electrostatic elements. Mass analysis is achieved using a 45° magnetic dipole midway along the flight path. Diagnostic elements positioned throughout the beamline are used to determine beam properties.

A radiation hard 2.45 GHz ECR source has been installed in the ISAC target station. The ion source with its 8–60 kV extraction system is coupled to the radioactive isotope production target via a short transfer tube. The volatile radioactive isotopes produced by bombarding a target with a 500 MeV proton beam, are ionized and accelerated at the ECR source system. The source is reengineered to withstand a dose rate of 105 Gy/h from the activation of the target by the 500 MeV, 100 mA proton beam. The whole assembly is located beneath a 2 m thick steel shielding structure. Design aspect of the source and the initial results obtained during the commissioning at the ISAC terminal, as well as preliminary results obtained at the test stand are presented.

The TRIUMF optically pumped polarized ion source presently produces a 15 μA dc beam of up to 80% polarized H − ions within a calculated normalized emittance of ≲ 0.16 π cm mrad. Extracted beam parameters, after acceleration by the TRIUMF cyclotron to 230 MeV, are ∼ 4 μA with a proton polarization of 75%. The source is based on optical pumping of Rb vapor by Ti:sapphire lasers, resulting in improved polarization compared to previous results using Na as the polarized medium. The instrumentation and results of a detailed study of parameter dependences are reported.

A 2.45 GHz electron cyclotron resonance ion source has been designed and built to ionize radioactive atoms and produce single charged ion beams for the isotope separator and accelerator at TRIUMF. The source is characterized by its short axial length (8 cm) and the small pair of magnetic coils (diam=φ26 cm) placed adjacent to the source cavity. A small diameter quartz tube is inserted in the cavity to confine the plasma to a small volume and to shorten total ion transient time for the exotic gaseous elements with short and intermediate half life. The computer code POISSON is used to design the magnetic coils. A three-electrode extraction system simulated with the code IGUNE is used to study the beam extraction efficiency. In this article the design of the source, extraction system, and the preliminary results on beam emittance and energy spread are presented; the results on ion transient time, ionization efficiency, and beam extraction efficiency are presented in a separate article.

A 2.45 GHz electron cyclotron resonance (ECR) ion source with a single mode resonator is being developed to produce high efficient single charged ion beams from exiguous gaseous elements. The source is intended to produce short and long half-life radioactive ion beams as well as stable ion beams for low and high energy experiments at ISAC [J. M. Poutissou, Proceedings of the ISAC Workshop (1994)]. It is obvious that for the radioactive ion beam production, the gas and ion transient time and the overall ionization efficiency are the most important parameters. The transient time is measured using ultrafast peizoelectric gas valve which could operate up to a frequency of 2 kHz. A unique feature of the source is that the plasma chamber is considerably smaller (∼170 times) than its resonance cavity in order to minimize the transient time. Quartz tubes with various diameters (5–20 mm) and 80 mm long are tested as the plasma chamber and the results are discussed. The effect of the transfer tube length, which lin...

In November of 1998, the ISAC radioactive beam facility at TRIUMF started delivering on-line isotope separated radioactive beams to experiments. A surface ionization source developed for ISAC has been used to commission the mass separator and beam transport systems and is providing radioactive beams to the first generation of ISAC experiments. The ion source is integral with the radioactive beam production target and is designed to be simple, radiation hard, inexpensive, and easily exchanged by remote-handling techniques. The ion source and its extraction column are suspended at the bottom of ∼2 m of steel shielding incorporated in the target module. The module is suspended in a vacuum tank with primary and secondary vacuum systems. All services for the target/ion source and beam extraction system are ducted through the module shielding. The first sets of beam transport elements and beam diagnostic devices are similarly suspended in vacuum at the bottom of two additional shielded modules. Ion beam charact...

Conference Proceedings can be submitted to Review of Scientific Instruments; International audience; Charge state breeding is an important ingredient of most post accelerators at ISOL facilities. It implies the transformation of singly or low charged ions extracted from the on-line target ion source system into highly charged ions, which are better suited for acceleration. For ISAC at TRIUMF the acceptance of the first part of the accelerator requires a maximum A/q value of 30. Further stripping of the ions is done at an energy of 150 keV/u to reach a charge state leading to an A/q value

The TRIUMF optically pumped ion source produces a polarized H− beam for injection into the TRIUMF 500 MeV cyclotron. After acceleration, protons are extracted from the cyclotron by stripping, producing more than 5 μA of average current at up to 53% polarization. The ion source consists of a 28 GHz electron-cyclotron-resonance proton source, an optically pumped sodium vapor charge exchange cell, a Sona type transition region and a sodium vapor negative ionizer. A dye laser system produces typically 6 W of light power at the sodium D1 absorption wavelength. The source construction and detailed characteristics are reported.

The off-line ion source (OLIS) terminal consists of a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source and an electrostatic switch that allows selecting any one of the sources without mechanical intervention. These sources provide variety of beams to ISAC experiments, for commissioning the accelerators, for setting up the radioactive experiments, and for tuning the beam lines. The microwave ion source has been operational since 1995 and provides singly and doubly charged beams from various stable isotopes for many ISAC experiments at high and low energy areas. Originally its prime goal was to provide beams from gaseous elements, but later two ovens and a sputtering system were added in order to provide beams from liquids and from solids. The surface ion source installed in 2002 can provide low energy spread beams from alkali and semialkali elements. It also has three separate ovens and an ionizer. Therefore, it can provide three different temperature regions simultaneously to provide different beams to ISAC. It is mainly used for laser spectroscopy experiments and other experiments, which require a finite beam quality. A hybrid surface-arc discharge ion source was also developed and installed in order to meet specific demands from experiments. This source terminal is now automated for start up and for mass selection. It is capable of providing stable beams for months without maintenance and it is also capable of providing negative ion beams if required. To date, over 40 different isotopes including many rear isotopes were delivered to various experiments from the OLIS source terminal. Performances of the ion sources and some of the results are discussed.

An off-line microwave ion source (TE111 mode resonator at 2.45 GHz) is being developed to produce stable ion beams for ISAC commissioning as well as to produce intermediate and long half-life radioactive ion beams for initial experiments. Two different sources have been constructed and tested. In the standard source configuration the microwave power is injected and the beam is extracted on axis. In the second source microwave power is injected radially. In this case, the beam is extracted radially. Each of the sources is capable of handling gaseous, metallic and volatile compounds. A three electrode extraction system and a mass spectrometer with a resolution of 1600 are used to analyze the beams. The performance of the two sources is compared. In a number of parameters, efficiency, power requirements, tuning simplicity and lifetime, the radial source out performs the axial source. The test results with both sources are present.

A multicusp source for positive ion beams has been designed and constructed in collaboration with the Ion Beam Technology Department of LBNL for the TRIUMF ISAC project. This type of source has demonstrated a high yield of singly charged ions, a low energy spread, a good emittance, and is compact and simple. Several stages of tests and measurements using nonradioactive beams to characterize the source performance are being carried out both at LBNL and at TRIUMF prior to the final phase of radioactive target-source system tests. Results of these nonradioactive tests and certain problems encountered are reported and discussed in this article.

A 45° parallel-plate energy spread analyzer has been designed and built for the ISAC project at TRIUMF. It features an energy resolution of ⩽0.04% and a spectrometer constant of k=1.29. Nineteen 0.1 mm by 10 mm metal guard frames with 1 MΩ resistors are used to equalize the electric field in the analyzer to an order of ⩽0.5%. Electric field simulation is done by a code POISSON. This article describes the design of the analyzer. Preliminary experimental results are also presented.

We have reported a 15 mA dc H− multicusp source at the sixth International Ion Source Conference in 1995 at Whistler. Since then, the H− beam has been further upgraded to 20 mA for 25 kV dc extraction. The D− beam output of the new cusp source has also been measured at 25 and 12.5 kV energies. An 8 mA D− peak current at 25 kV with 0.5 π mm mrad normalized 4 rms emittance has been obtained. Special attention was given to the effects of gas flow, pumping speed, and neutralization on the 12.5 kV operation which is used for the D− injection into a 15 MeV D− cyclotron. At present, we are making an effort to test the effect of injecting Cs in the vicinity of the plasma aperture. On the other hand, a hybrid of filament plus LaB6 cathode mechanism has been tested for filament lifetime issue. The results from these tests are reported. In particular, the experience in operating this new source for the Triumf/Nordion TR30 cyclotron is summarized.

A 2.45 GHz ECRIS was built at TRIUMF for on‐line applications at the ISAC facility. The ISAC facility utilizes a 500 MeV proton beam driver with intensity that can reach 100 μA on the isotope production target. In such an environment special care during the design phase had to be taken, all the ECRIS components especialy the two coils had to be radiation hard. Following a disappointing run with a Ta foil target intensive studies were carried out to determine the relationship between the ionization efficiency and the gas pressure in the ion source. The Neon ionization efficiency decreased from 2% to 0.01% when the tank pressure surrounding the ECR increased from 1.5×10−6 to 3×10−6 Torr. This pressure increase corresponds to approximately 1014 Kr/s and 5×1013 Xe/s. In May 2004 additional on‐line tests with a SiC target were undertaken. The goal was to produce 18Ne for a high precision half‐live determination. Again when operating the ECRIS with the same operating parameters as the ones obtained off‐line the ionization efficiency decreased when the target was bombarded with more that 5μA. After modifying the ECRIS operating conditions by injecting only Ar as a support gas and the proton beam could be increased up to 30 μA, which is the nominal for a SiC target.

A 15 mA dc H− multicusp source has been developed for injection into a TR30 cyclotron. This source is also used with a 900 kV tandem accelerator to obtain 10 mA protons at 1.8 MeV. The program is an extension of the 5–7 mA dc H− cusp source developed at TRIUMF during 1989–1990. Major efforts include the search for the optimal filament materials, shape, and location; comparison of cusp line confinement and magnetic filtering of electrons at the extraction region; optimization of extraction lense configuration; and upgrading of vacuum and power systems capability. The source is noncesiated and the maximum arc power available is only 5 kW. After the H− beams pass through an electron suppression grid and a 20 mm collimator, we obtained 15 mA with 0.66 π mm mrad 4 rms normalized emittance. At this output the e/H ratio was about 4. The best normalized emittance occurs around 5–7 mA, having a value of 0.37 π mm mrad. Further development in the near future is planned using cesium and multiple apertures in the hope of increasing dc H− currents to 30 mA while holding the normalized emittance below 0.75 π mm mrad.

A microwave‐driven ion source being developed at TRIUMF is designed to produce stable, reliable, and gas‐efficient negative and positive ion beams for cyclotrons and other accelerators. The source has been tested for H− and achieved 2.1 mA at 0.25 π mm mrad normalized emittance for 500 W of input power at a frequency of 2.45 GHz. The source was operated over one month without interruption for a H− beam stability test and demonstrated 2.5% stability over the period. For positive beam extraction H+, He+, N+, and Ar+ species have been studied. A 2 mA N+ beam was obtained at 0.3 π mm mrad normalized emittance for 1 kW of input power. A beam density as high as 7 mA/cm2 with 45% gas efficiency has been achieved for the Ar+ beam. In this paper the source parameters and characteristics are discussed.

For the acceleration of radioactive ions the usable mass range is limited by the A/q acceptance of the first accelerator stage. Since an efficient primary ion source normally produces singly charged ions, charge state breeding is necessary if higher masses are to be accelerated. At TRIUMF an ECR source has been chosen as a breeder due to its potential high efficiency in producing intermediate A/q values. To minimize the necessity for further stripping an A/q around 6 is desirable. A 14 GHz "PHOENIX" booster from Pantechnik has been set up on a test bench. The singly charged ions are produced from different ion sources, wihich can be mounted in a standard ISAC target-ion-source set-up. For the first tests an ECR source to produce noble gas beams has been chosen. The aim of the measurements at the test bench is to find the optimum operation conditions of the charge state booster and the injection and extraction ion optics. Working with radioactive ions always means that the system should aim for high efficiency, as the production of such species is limited. Therefore, special emphasis has to be put on the highest yield for the production of the desired charge state. A second point is the analysis of the extracted beam quality in order to optimize mass separation and transport efficiency. The paper shows the status of the set-up and reports on first results of the charge breeding of Ar, Ne and Xe. With Xe a total efficiency of 22.5% has been achieved.

Several H−/D− dc sources employing multicusp confinement and magnetic filtering to enhance H−/D− production have been designed, built, and tested. Source performance in terms of beam output, emittance merit as functions of arc current, confinement magnetic strength, plasma volume, beam exit diameter, and extraction lens configuration have been studied in detail. At present, up to 9 mA H− and 3 mA D− beams with a normalized emittance of 0.44 mm mrad for H− beam have been extracted. A number of sources are tailored to fit the requirements of individual projects. In this article, a general description of source structure, power and biasing algorithms, and extraction geometries of these cusp sources will be given.

The initial goal of a polarized proton beam extracted from the TRIUMF (Tri-University Meson Facility) cyclotron, having a current of 5 mu A with 60% polarization, has been achieved with the development of the optically pumped polarized H/sup -/ ion source. This beam is now being used to produce an intense secondary beam of polarized neutrons for the TRIUMF experimental program. Much of the recent development effort has addressed the reliability requirements for routine operation. Recent results from using the system are described with emphasis on the laser stabilization subsystem, the modifications to the electron cyclotron resonance proton ion source (ECRIS), the sodium charge exchange cells and the development of a low energy polarimeter. Also discussed are the developments which should lead to a higher polarization. >

A multicusp source for positive ion beams has been designed and constructed in collaboration with the Ion Beam Technology Department of LBNL for the TRIUMF ISAC project. This type of source has demonstrated a high yield of singly charged ions, a low energy spread and a good emittance and is compact and simple. Several stages of tests and measurements using non-radioactive beams to characterize the source performance are being carried out both at LBNL and at TRIUMF prior to the final phase of radioactive target-source system tests. Results of these non-radioactive tests and certain problems encountered are reported and discussed in this paper.

The TRIUMF optically-pumped polarized H/sup -/ ion source (OPPIS) produces in excess of 150 /spl mu/A DC of H/sup -/ ion current at 85% polarization within a normalized emittance of 0.8 pi mm mrad. A 20 /spl mu/A beam was accelerated to 500 MeV through the small acceptance of the injection line and the cyclotron. A feasibility study of higher current production for application to multi-GeV accelerators has been performed. A polarized H ion current of 1.6 mA within a normalized emittance of 2.0 pi mm mrad was obtained after upgrading the ECR primary proton source. The source performance now well exceeds the original design parameters and clearly confirms the potential of the OPPIS technique for other accelerators.

The TRIUMF optically pumped polarized H− ion source has been modified to operate with rubidium as the optically pumped medium. The intrinsic characteristics of rubidium as well as an increase in laser power, compared with the previous system based on sodium, have led to a large increase in beam polarization to over 75%. A proton current of 2.5 μA extracted from the TRIUMF cyclotron at 230 MeV was easily attained during initial operations.

Two versions of injection line matching sections between the external ion source and the spiral inflector are used for the compact cyclotrons developed at TRIUMF in cooperation with Ebco Technologies. The 30 MeV model adopts a solenoid-doublet (SQQ) version while the 19 MeV unit takes a four quadrupole/two quadrupole (4Q/2Q) option. Both cyclotrons use a same type of H cusp source and an identical inflector-central region combination. A comparison has been made between these two systems, in terms of DC transmission and RF acceptance as a function of source's H current intensity and emittance. The design and optics characteristics for both systems are described and the results obtained are reported.

The modulation of polarized current correlated with spin‐reversal has been measured for the first time in Optically Pumped Polarized Ion Source (OPPIS). The modulation amplitude depends on the density of the optically pumped Rb vapor and the energy of the primary proton beam in OPPIS. Several physical processes contribute to the current modulation. By optimizing some of the source parameters, the current modulation was reduced to less than 10−5, as measured at 220 MeV in a transverse electric field ionization chamber, part of a parity violation measurement detector system. This is close to the stated requirements of the approved parity violation experiment. A technique of laser control for fast (up to 200 times per second) spin‐flip has been developed which should provide for precision control of optical pumping and maintain the spin correlated current modulation below the 10−5 level.

The Off-Line Ion Source (OLIS) [K. Jayamanna, D. Yuan, T. Kuo, M. MacDonald, P. Schmor, and G. Dutto, Rev. Sci. Instrum. 67, 1061 (1996); K. Jayamanna, Rev. Sci. Instrum. 79, 02711 (2008)] facility consists of a high voltage terminal containing a microwave cusp ion source, either a surface ion source or a hybrid surface-arc discharge ion source [K. Jayamanna and C. Vockenhuber, Rev. Sci. Instrum. 79, 02C712 (2008)], and an electrostatic switch that allows the selection of any one of the sources without mechanical intervention. These sources provide a variety of +1 beams up to mass 30 for Isotope Separator and ACcelerator (ISAC) [R. E. Laxdal, Nucl. Instrum. Methods Phys. Res. B 204, 400 (2003)] experiments, commissioning the accelerators, setting up the radioactive experiments, and for tuning the beam lines. The radio frequency quadrupole (RFQ) [M. Marchetto, Z. T. Ang, K. Jayamanna, R. E. Laxdal, A. Mitra, and V. Zvyagintsev, Eur. Phys. J. Spec. Top. 150, 241 (2005)] injector accelerator is a constant velocity machine designed to accept only 2 keV/u and the source extraction energy is limited to 60 kV. Further stripping is then needed downstream of the RFQ to inject the beam into the drift tube linac [M. Marchetto, Z. T. Ang, K. Jayamanna, R. E. Laxdal, A. Mitra, and V. Zvyagintsev, Eur. Phys. J. Spec. Top. 150, 241 (2005)] accelerator that requires A/q up to 6. Base on this constraints a multicharge ion source capable to deliver beams above mass 30 with A/q up to 6 was needed in order to reach full capability of the ISAC facility. A Supernanogan [C. Bieth et al., Nucleonika 48, S93 (2003)] multicharge ion source was then purchased from Pantechnik and was installed in the OLIS terminal. Commissioning and performance of the Supernanogan with some results such as emittance dependence of the charge states as well as charge state efficiencies are presented.

ISAC is an accelerator facility primarily dedicated to astrophysical studies. Off-line and online ion sources provide up to 65 keV of stable and radioactive beams to the ISAC accelerators. Initial acceleration is done via a constant velocity radio frequency quadrupole that requires 2 keV/u. Then the beam is further accelerated to 1.5 MeVu at ISAC-I and 6.5 MeV/u at ISAC-II. To study radiative capture reactions relevant for astrophysics, the recoil mass spectrometer DRAGON was built in the experimental area. (40)Ca(alpha,gamma)(44)Ti is identified as one of the key reactions in supernovae to produce (44)Ti and is given highest priority. For this experiment, an ultrapure Ca(+2) beam was requested from the off-line ion source. Initial tests showed that, when using conventional ion sources, (40)Ar and (40)K are the impurities that are most difficult to eliminate. In order to overcome this problem, a new concept was needed and the hybrid surface arc discharge ion source was born. The hybrid surface ion source consists of a small surface ionizer and an arc discharge placed in a solenoid field. A very low ratio of (40)Ar/(40)Ca=8 x 10(-5) was achieved with this new source and the experiment was completed successfully. The source is described in detail and its performance is discussed in this article.

An ECR ion source is converted to produce a beryllium fluoride beam, which will be stripped to 7Be+2 beam and used in 7Be(p,γ)8B experiments at ISAC. The source consists of an injection chemical chamber and a plasma chamber. Chemically purified (99.9%) BeO is placed in the chemical chamber which can be heated up to 1000 °C. A CF4 leak connected to that chamber serves as the source of CF4 for the reaction to produce BeF2. The BeF2 is then injected into the hot electron layer region of the plasma chamber to enhance the ionization efficiency. A detailed source description, beam parameters and ionization efficiency measurements are presented in this paper.

At TRIUMF, H− ion sources have been characterized on a teststand to improve the understanding of their performance. Measured beam characteristics such as current, emittance, and e∕H− ratio were correlated with source conditions as a function of relevant plasma parameters. Plasma densities, temperatures, and plasma potentials were measured with a Langmuir probe and correlated with beam properties for different confining magnetic fields and different values of arc power and gas pressure. The mechanism of beam extraction was studied by correlating plasma potential profiles with the corresponding plasma electrode bias voltages obtained from optimizing ion source outputs. Experiments with collar biasing and noble gas mixing were unsuccessful because of undesirable plasma potential profiles.

An electron cyclotron resonance ion source was developed and installed for radioactive ion beam production from gaseous elements at ISAC/TRIUMF. A single mode resonator was used as the microwave cavity and a small quartz tube (70 times smaller than the cavity itself) was placed in it to define the plasma boundaries. The main design considerations were given to the transit time, reliability, and efficiency as well as radiation hardness to a dose rate of about 105Gy∕h. The transit time and the efficiency of the source for inert gases ranging from helium to xenon are presented. The technical and fundamental aspects of the source as well as the unique features due to the design constrains at the ISAC online terminal are also briefly discussed in this article.

An on‐line emittance–mass scanner (EMS), with a size of 10 cm×10 cm×8 cm, has been developed for use with low energy and light ion beams (A

TRIUMF presently uses a Lamb-shift polarized H− source capable of providing ~1 μA of ~75% polarized beam on target. This current is barely adequate for a number of approved experiments. Since 1983 an optically pumped source has been under development at TRI- University Meson Facility of Canada (TRIUMF). This is expected to eventually produce intense dc H~ beams (~50 μA) at a polarization of ~70%, with an emittance suitable for injection into the cyclotron. Approximately 50% of the dc ion source beam will be accelerated to full energy and extracted. To date, the optically pumped source has been shown to be capable of ~10 μA of H− at a polarization of ~60% within a normalized emittance of 0.4π mm-mrad and at an ionizing field of 1.5 kG. Work has begun on attaching the source to the cyclotron.