Transcript Slide 1
Laser Ablation Characterization in LNL D. 1 Scarpa , P. 2,3 Nicolosi , A. 2 Franci , A. 6 Tomaselli , 1 Manzolaro , 1,4 Corradetti , 1,5 Vasquez , M. S. J. 1 1 1 1 1 M. Calderolla , A. Monetti , M. Lollo , A. Andrighetto , G. Prete . M. 1 Rossignoli , 1.INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy. 2Dipartimento di Ingegneria dell'Informazione, 2.Università degli Studi di Padova. 3 IFN-CNR UOS Padova 4Dipartimento di Scienze Chimiche dell’Università di Padova, Padova, Italy. 5 Dipartimento di Ingegneria dell'informazione dell’Università di Padova, Padova, Italy. 6 Università degli Studi di Pavia, Dipartimento di Ingegneria Industriale e dell'Informazione,, Via Ferrata 1, Pavia, Italy. Laser Ablation Ablation Chamber Setup An high power laser pulse focalized onto a surface (target) is capable to produce a rapid local increase of the temperature. This process implies an evaporation or direct sublimation of part of the target material. If laser power density in space and time is enough is possible to have formation of high density plasma, and production of high charge state ions, expelled from the target surface. Preliminary studies of these processes are starting in new SPES Laser Laboratory in Laboratori Nazionali di Legnaro. The aim of this work is to start investigation and building first know-how on Laser Ion Sources. Ablation Vacuum Chamber was entirely designed in LNL, it can reach vacuum down to 10-6 mbar by diffusion oil pump. It guests ablation target, ion collector and several electrical connections. ND:YAG Laser Ablation laser is a QUANTEL YG 980 Nd:YAG laser. It is capable of 2 J, 20 nsec pulses at maximum repetition rate of 10 Hz. First tests: As first test we decided to duplicate a documented experimental setup to certify our equipements. ↑ΔV ↑ΔV This setup was chosen due to its simplicity, involving only a target and a collector plate. Successive improvements was implemented adding plates polarization by high voltage generator. Measurements results: Pulse duration Several power regime used during the experiments are characterized by different pulse durations from 100 to 10 ns. Data show good qualitative agreement between the reference work and our preliminary measurements. Spot size Collector signal Target signal Ablated area measurements will provide a preliminary quantity of vaporized material to compare with ion current data. Further measurements are planned using microscopes. Current measurements at the polarized collector. Results shows several peaks due to several ion state of charge. Some peaks are due to impact of neutral material on collector which extract electrons. Current measurements at the polarized target. Varying polarization voltage show several peak appearing and disappearing due to their state of charge. Future developements: The vacuum chamber will be updated to guest a Time of Flight mass spectrometer. Thank to this improvement it will be possible to fully characterize the state of charge of the ions coming out from the plasma plume. LNL new laser laboratory evolution 1/2 Since March 2013 a new laser laboratory is operative in LNL. In this laboratory is nowadays present a Nd:YAG Quantel Laser used for ablation studies and will be housed and tested the new all solid state tunable laser system for the SPES project.