Status of the CO2 laser ion source at CERN

Fournier, P. G.; Grégoire, Guillaume; Kugler, Hartmut; Haseroth, H.; Lisi, N.; Meyer, C.; Ostroumov, P. N.; Schnuriger, J C; Scrivens, R.; Rodriguez, F. Varela; Wolf, B. H.; Homenko, S.; Makarov, K. N.; Satov, Yu. A.; Stepanov, A.; Kondrashev, S.; Sharkov, B.; Shumshurov, A.

doi:10.1063/1.1150347

Cited by 25 publications

(6 citation statements)

References 5 publications

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“…4,5 More modern systems have been built upon the previous success and the growth in interest in heavy ion accelerators. [6][7][8][9] In parallel with new developments in Q-switched lasers, LIS systems utilizing CO 2 , excimer XeCl, femtosecond Ti:sapphire, and picosecond Nd:yttriumaluminum-garnet lasers have all been reported. 10 In this paper we shall present a thorough overview of the main components and design aspects of the DCU laser ion source.…”

Section: Introductionmentioning

confidence: 99%

The DCU laser ion source

Yeates¹,

Costello

Kennedy

2010

Review of Scientific Instruments

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Laser ion sources are used to generate and deliver highly charged ions of various masses and energies. We present details on the design and basic parameters of the DCU laser ion source ͑LIS͒. The theoretical aspects of a high voltage ͑HV͒ linear LIS are presented and the main issues surrounding laser-plasma formation, ion extraction and modeling of beam transport in relation to the operation of a LIS are detailed. A range of laser power densities ͑I ϳ 10 8 -10 11 W cm −2 ͒ and fluences ͑F = 0.1-3.9 kJ cm −2 ͒ from a Q-switched ruby laser ͑full-width half-maximum pulse duration ϳ35 ns, = 694 nm͒ were used to generate a copper plasma. In "basic operating mode," laser generated plasma ions are electrostatically accelerated using a dc HV bias ͑5-18 kV͒. A traditional einzel electrostatic lens system is utilized to transport and collimate the extracted ion beam for detection via a Faraday cup. Peak currents of up to I ϳ 600 A for Cu + to Cu 3+ ions were recorded. The maximum collected charge reached 94 pC ͑Cu 2+ ͒. Hydrodynamic simulations and ion probe diagnostics were used to study the plasma plume within the extraction gap. The system measured performance and electrodynamic simulations indicated that the use of a short field-free ͑L =48 mm͒ region results in rapid expansion of the injected ion beam in the drift tube. This severely limits the efficiency of the electrostatic lens system and consequently the sources performance. Simulations of ion beam dynamics in a "continuous einzel array" were performed and experimentally verified to counter the strong space-charge force present in the ion beam which results from plasma extraction close to the target surface. Ion beam acceleration and injection thus occur at "high pressure." In "enhanced operating mode," peak currents of 3.26 mA ͑Cu 2+ ͒ were recorded. The collected currents of more highly charged ions ͑Cu 4+ -Cu 6+ ͒ increased considerably in this mode of operation.

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Section: Introductionmentioning

confidence: 99%

The DCU laser ion source

Yeates¹,

Costello

Kennedy

2010

Review of Scientific Instruments

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“…This reduces the extracted plasma plume density and ensures thermalization of the ion kinetic energies [2,3] At this point the plasma plume is a collection of neutrals and charged particles moving at uniform velocities and displaying a small velocity gradient from front to back. While this reduces the challenges of high voltage extraction and beam transport, it strongly limits the peak current and charge state which can be extracted.…”

Section: Discussionmentioning

confidence: 99%

“…Laser ion sources (LIS) [1][2][3], radiofrequency (RF) [4,5] or microwave sources [6,7], insertion devices like wigglers and undulators and related free electron laser (FEL) devices [8][9][10], linear particle accelerators (LINAC) [11,12] and e -guns [13,14] amongst others. To usefully employ the resultant electron or ion bunches, electrostatic and/or magnetic optics for transport and manipulation are often essential.…”

Section: Introductionmentioning

confidence: 99%

Charged particle dynamics in a ‘high-pressure’ laser ion source

Yeates¹,

Costello²,

Kennedy³

2011

J. Phys. D: Appl. Phys.

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Abstract. Charged particle sources require beam transport techniques specific to the application for optimum operation. The complexity of techniques increases as the degree of ionization and kinetic energy of charged particles increases. The Dublin City University laser ion source (DCU -LIS) utilizes a short field region (L = 48 mm) to maximize the average charge state and peak current extracted, thus ion extraction occurs at 'high -pressure'. The presence of large space charge forces, high average plasma plume temperature and the expansion dynamics of laser generated plasmas result in significant divergence of the ion bunch upon injection into the drift tube. To facilitate efficient beam transport, and to maximize system throughput, we employ a rather unique electrostatic transport system, termed a 'continuous einzel array' (CEA). Ion electrodynamics in such a system exhibit a number of distinct features which modify the system performance and alter the expected distribution of kinetic energies (K E ), the times of flight (TOF) and ion bunch diameters. System scalability in regard to beam 2 kinetic energy is also important. In this paper the superior performance of the LIS equipped with a CEA is compared to a traditional einzel lens electrostatic beam transport system based on the usual three element and also a five element lens system.

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“…The LIS at CERN has used both two solenoids and a Gridded Electrostatic Line (GEL) [4], shown in Figure 4a, to try to focus the high current, multiple charge-state beam into the RFQ. Additionally a one solenoid line was also investigated but has so far not been coupled to the accelerator.…”

Section: Experimental Observationsmentioning

confidence: 99%

Aberrations due to solenoid focusing of a multiply charged high-current ion beam

Grégoire

Kugler

Lisi

et al. 2000

Review of Scientific Instruments

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At the output of a laser ion source, a high current of highly charged ions with a large range of charge-states is available. The focusing of such a beam by magnetic elements causes a non-linear space-charge field to develop which can induce large aberrations and emittance growth in the beam. Simulation of the beam from the CERN laser ion source will be presented for an ideal magnetic and electrostatic system using a radially symmetric model. In addition, the 3D software KOBRA3 is used for the simulation of the solenoid line. The results of these simulations will be compared with experiments performed on the CERN laser ion source with solenoids (resulting in a hollow beam) and a series of gridded electrostatic lenses.

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Status of the CO2 laser ion source at CERN

Cited by 25 publications

References 5 publications

The DCU laser ion source

The DCU laser ion source

Charged particle dynamics in a ‘high-pressure’ laser ion source

Aberrations due to solenoid focusing of a multiply charged high-current ion beam

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