MeV Particles, Huge Impact, Soft Desorption.

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1 MeV Particles, Huge Impact, Soft Desorption. S. Della-Negra Institut de Physique Nucléaire d Orsay, UMR 8608 CNRS- Univ. Paris-Sud, F-91406Orsay Cedex (dellaneg@ipno.in2p3.fr) Since the first PDMS experiment performed by R.D. Macfarlane and T.D. Torgerson 1, a great number of data were provided thanks to the high energy atomic ion beams. These allow varying the energy density deposited near the solid surface by varying the energy and the charge state of these particles from MeV to GeV and from one to 70 charges. I shall start my talk by pointing out results of secondary ion emission (SI) obtained with high energy atomic ions at the surface and from the deep layers; the maximum depth for the ionic emission is around 10 nm depending on the SI. These studies demonstrate that the energy density in the track is the main parameter. The question that arises is the development of a MeV-SIMS instrument complementary to other methods already available as IBA techniques by using small Van de Graaff or Tandem accelerators 2. The possibility to deliver heavy ion (oxygen to copper) micro-beams permits to develop Mass Spectrometry (MS) ion imaging 3 correlated with µ-pixe, µ-rbs techniques. A second development concerns SIMS analysis at ambient pressure. 4 It is very promising to obtain an image of the sample at ambient or low pressure. Now, the enhancement of the SI yield leads to an increase of the energy density deposit, therefore to the use of clusters as projectiles. The second part of my presentation concerns cluster ion beams. More than fifteen years ago, the fundamental interest of the cluster ions was clearly shown and within a few years we had a whole set of source and accelerator facilities to cover a large energy and mass range: from kev to MeV and clusters from some carbon or gold atoms to the molecules like fullerenes. I will point out certain results obtained a few years ago and illustrate the cluster-solid interaction by presenting results about the modifications induced in the material by atomic and cluster impacts. The object of my talk is to synthesize the information which can be extracted from a large projectile energy and mass range. Then I shall try to deduce, from this synthesis, the advantages for the SIMS surface analysis, of the various beams which can be accelerated by small electrostatic accelerators like van de Graaff or Tandem in the energy range from 1 to 4 qmev. In conclusion I shall recall the outstanding facts of these studies. Is there really a universal probe? Which is the best mass-energy compromise which makes it possible to sublimate and ionize the largest volume of matter near the surface? Pegase in the hundred kev range at TAMU and Andromede in the MEV range at Orsay are exploring the nanoparticle micro-beams as a new probe for mass spectrometry Imaging. 5 1 RD Macfarlane and DF Torgerson, Science Vol. 191 no (1976), Jones BN, Palitsin V, Webb R. NIM B, 268 (11-12), (2010), Y.Wakamatsu, H.Yamada, S.Ninomiya, B.N.Jones, T.Seki, T.Aoki, R.P.Webb, J.Matsuo, NIMB, 269, (2011), J. Matsuo, S. Ninomiya, H. Yamada, K. Ichiki, Y. Wakamatsu, M. Hada, T. Seki, & T. Aoki, Surf. & Interface Anal., 42, 2010,

2 MEV PARTICLES, HUGE IMPACT, SOFT DESORPTION. S. Della-Negra Institut de Physique Nucléaire d Orsay, UMR 8608 CNRS-IN2P3, Univ. Paris-Sud, F-91406Orsay Cedex (dellaneg@ipno.in2p3.fr) Unité mixte de recherche CNRS-IN2P3 Université Paris-Sud Orsay cedex Tél. : Fax :

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6 0.5 MeV/u = 1 cm/ns 5

7 Accelerator Facilities Advantage : To control all Solid-particle interaction parameters 1. The energy deposited in the solids versus the energy loss measurment, de/dx (V) = f(sample thickness) 2. The energy density versus the projectile velocity (δ electron range gives the radius of the initial track). 3. The projectile charge state permits to modify the deposited energy near the surface and to probe the emission depth de/dx α Q 2 Q (V) = f(sample thickness) 6

8 0.5 MeV/u S O 7

9 vendredi 25 septembre 0.5 MeV/u 0.5 MeV/u 8

10 H +, M +/- q i,1 MeV/u H + emission independent of the projectile Surface interaction < 1nm And molecular ion emission: NO Volume of interaction Depth ~10-20 nm Charge state 9

11 SI Yield vendredi 25 septembre (M+H) + and C + PI : q, M & Z Phenylalanine Sample

12 62 M1/6 M1/6 M2 M2 12 M1/6 M2 11

13 (M-H) - (M 2 -H) - (M 3 -H) - I Beam The steeper slope for the large molecular Ion yields indicates that they originate from a smaller depth. Dimer and trimer have higher chance to escape without dissociation from the upper layers 12

14 The maximum SI yield is reached around 0.5 Mev/u (1 cm/ns) -The studies of the projectile velocity and the energy loss in the matter demonstrate that the energy density in the track is the main parameter. SI yield ~ (de/dx) 2 -The knowledge of the charge state evolution inside the solid and thus of the energy loss permits to probe the energized volume taking part in the ionic emission H + and C + ions are emitted from the zone of impact in a time of about sec and the emission depth is around 1 nm; On the contrary the molecular and cluster ion emission are emitted from the deep layers. The volume of interaction depth is between 10 and 20 nm and the maximum depth for the ionic emission is 10 nm. 13

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18 U ions at 1 GeV de/dx 4 kev/å C 60 at 30 MeV de/dx> 4 kev/å de/dx (C n ) = n de/dx (C 1 ) U GeV e - Radius e - C 60 r e - e - Each carbon = 500 kev Large range of electrons (R>100nm) Large volume of transient energy deposition SMALL DENSITY small range of electrons (r~ nm) Small volume of transient energy deposition LARGE DENSITY 17

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20 ORGANIC CRYSTALS vendredi 25 septembre 10 7 amu 19

21 Yield = 100 times the yield measured with MeV ions 20

22 Au 11 Atomic Force Microscope Measurements E =1.4 MeV Gold Target Range = 120 Å (de/dx) nuc = 100 kev/nm 21

23 40 kev/ atom 22

24 40 kev/ atom 23

25 Yield vendredi 25 septembre Au ? 0,5 0,4 0,3 Phenylalanine target, (M-H) -, m/z Au 9 Au 4 Au 3 0,2 Au 2 0,1 Au kev 10 kev 0, Energy per atom (kev/atom) Phys. Rev. A 63 (2001)

26 Andromede Pegase 25

27 Poster n ClTuP2 26

28 1-The accelerators are available (electrostatic accelerator from 1 to 8 MV) for: IBA (MeV Ion Beam Analysis) techniques, ranging from PIXE (Particle Induced X-ray Emission) and PIGE (Particle Induced Gamma-ray Emission) to RBS (Rutherford Backscattering Spectroscopy), IBIC (Ion Beam Induced Charge) and IBIL (Ion Beam Induced Luminescence). And also AMS (Accelerator Mass Spectrometry) 2-It is possible to extract MeV ions into air through a thin window. 3-A conventional scanning microprobe using a heavy ion can be used to produce MeV-SIMS maps of molecular material. 4-simultaneous PIXE, RBS and SIMS measurements can be made using the same ion beam providing complementary measurements of the sample. 27

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30 SIMS XVII, Toronto 29

31 Rat Cerebellum MeV ions & Water T Seki et al NIM B. Volume 332, 2014, Pages

32 Ambient pressure MeV-SIMS set-up for molecular imaging at the submicron scale, University of Surrey 31

33 Dr Melanie Bailey Department of Chemistry, University of Surrey, Guildford, UK For fingerprint: SIMS : high resolution imaging in situ, relative quantification, depth profiling MeV SIMS : similar to SIMS, + in air analysis GSR : PIXE + MeV SIMS could give enhanced discrimination of GSR particles from different sources or for Pb-free ammunition PIXE can solve isomeric interferences with SIMS MeV SIMS : in air analysis is possible : General conclusion MeV SIMS could be useful in forensic science for applications where molecular imaging in air analysis is necessary Deposition sequences Fingerprint imaging Chemical profiling of fingerprints Gunshot residue analysis (GSR) MJ.Bailey, B.N.Jones, S.Hinder, J.Watts, S.Bleay & R.P.Webb, Nucl. Instrum. & Meths. B, 268(11), , (2010) N.J.Bright, R.P.Webb, S.Bleay, S.Hinder, N.I.Ward, J.F.Watts, K.J.Kirkby & M.J.Bailey, Anal. Chem., 84(9), , (2012) 32

34 Relative Quantification G. Spoto and G. Grasso; spatially resolved mass spectrometry in the study of art and archeological objects, Trend in Analytical Chemistry, 2011, 30,

35 High secondary ion yields are obtained with swift heavy ions in the MeV range. MeV cluster beams are probably better Molecular imaging has been demonstrated with µm resolution by using heavy atomic ions. Next step MeV cluster beams Heavy ion microprobe works at high pressure (a few tens to hundreds Pa) & permits to obtain ion imaging of tissues at the µm level. Natural matrix: the water is a good help for this analysis. Next step : MeV nanoparticles in air without window Simultaneous complementary analysis under vacuum or in air with µ-iba techniques (good quality images) give elemental composition and quantitative measurments. 34