Paulus, G.

Quint, W.

Ringleb, S.

Stöhlker, T.

Vogel, M.

GSI Repository

The HILITE Penning trap experimentM. Vogel1, S. Ringleb4, W. Quint1,2, G. Paulus3, and Th. Sto¨hlker1,3,41GSI, Darmstadt; 2Ruprecht Karls-Universita¨t Heidelberg; 3Universita¨t Jena; 4Helmholtz-Institut JenaWe have built a dedicated Penning trap setup for thepreparation of suitable ion targets for irradiation with high-intensity laser light, and the study of subsequent reac-tions. Of particular interest is the detailed investigationof multiphoton-ionisation of confined particles by highlyintense laser light. One important aspect is control overthe confined particles’ mass, charge, density, localizationand optimized overlap with the laser light by Penning traptechniques like the use of trap electrodes as ’electrostatictweezers’ and by application of a ’rotating wall’, respec-tively [1]. Also, the non-destructive detection of reactionproducts is a central property. The Penning trap setup isdesigned in a portable fashion, such that it can be attachedto existing laser systems easily, see figures 1 and 2.The interaction of highly intense radiation with matterand the corresponding non-linear effects have been subjectof lively research, both theoretical and experimental, es-pecially in the infrared and visible photon energy regimes.Laser systems capable of producing high intensities alsoat photon energies in the extreme ultra-violet (EUV) and(soft) X-ray regime open access to novel effects like non-linear Compton effects or simultaneous elastic and inelasticphoton scattering, and allow multiphoton-ionisation exper-iments in a new domain. However, experiments have so farnot been able to prepare and investigate well-defined parti-cle ensembles and to non-destructively analyse the reactionproducts with high accuracy, nor were they able to select orprepare products for further studies in a well-defined way.Figure 1: Cut through the HILITE setup in its current statewith the Penning trap in the centre of the superconductingmagnet.The particles (atomic or molecular ions) are confinedin the Penning trap following in-trap production or cap-ture of externally produced ions. Confined ions can becooled, compressed, positioned and selected with respectto their mass and charge prior to laser irradiation. The reac-tion products are analysed by non-destructive methods andhence remain confined for further studies. Such measure-ments are, for example, able to determine cross sections formultiphoton-ionisation in an energy- and intensity- regimeso far not or not sufficiently examined. Additionally, thecreated electrons may be extracted from the trap and anal-ysed externally. Hence, the reaction energetics may be re-constructed as completely as possible.Figure 2: Photograph of the HILITE superconducting mag-net setup currently located at the HITRAP facility.We have completed the vacuum system and thermal ra-diation shielding which hosts the Penning trap inside themagnet bore, and cooled it to cryogenic temperatures us-ing a two-stage cryo-cooler. The magnet has been operatedat fields up to 6 T and the vacuum system has successfullybeen tested to leak rates below the 10−10 mbar l/s scale. Wewill now focus on the operation and detection electronics aswell as on connectivity to an external (EBIT) ion source forhighly-charged ions.References[1] M. Vogel, W. Quint, Th. Sto¨hlker and G.G. Paulus, Nucl.Inst. Meth. B 285, 65 (2012).APPA-MML-AP-04 GSI SCIENTIFIC REPORT 2014218 DOI:10.15120/GR-2015-1-APPA-MML-AP-04

The HILITE Penning trap experiment

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The HILITE Penning trap experiment

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