Burchard, M.

Dedera, S.

Glasmacher, U. A.

Schöppner, N.

Trautmann, C.

GSI Repository

New approach to investigate irradiated calcite crystals – UV Raman andPhotoluminiscence with UV excitation ∗S. Dedera † 1, N. Scho¨ppner1, U. A. Glasmacher1, M. Burchard1, and C. Trautmann2,31Institute of Earth Sciences, University Heidelberg; 2GSI Darmstadt; 3Technical University DarmstadtIn the past, calcite (CaCO3) turned out as a sensitive nat-ural detector for ion defects. Additional experiments shallnow reveal, if there are more useful properties of this verycommon mineral.During a test experiment at the SIS, a trigonal calcitecrystal of 6×6.5×4 mm3 in size was irradiated with 192MeV/u 238U ions of fluence 1×1011 cm−2 (subsequentlydenoted as SIS-calcite). We observed a pronounced iono-luminescence and unexpected long phosphorescence forabout 20 min, which was not reported so far.Crystals from the calcite family are known to lumines-cent under UV excitation [1]. We thus exposed the SIS-calcite offline with UV light of wavelengths λL =366 nm(“long UV”) and λS=254 nm (“short UV”) to investigatewhether the increase of defect concentration through ionirradiation changed the properties of the SIS-calcite.No luminescence was detected for the “long UV”-excitation, whereas under the “short UV” excitation theSIS-calcite showed a thin line of greenish to yellowish lu-minescence localized around to the range where the elec-tronic energy loss of the ions is maximum. The rest of thecrystal did not contribute to luminescence.Trigonal calcite crystals irradiated at the UNILAC with11.1 MeV/u 197Au-ions showed the same greenish to yel-lowish luminescence when stimulated with “short UV”.The luminescence starts to become visible at a fluenceof 1×109 ions/cm2. Subsequently, experiments with UV-stimulated Raman spectroscopy and photoluminescence(PL) were performed to test the luminescence response toUV stimulation. The work is motivated by the expectationthat a UV-stimulated change in the luminescence patternmay be a suitable non-destructive analytical technique toquantify defect concentrations in calcite crystals producedby bombardment with heavy ions in the low fluence regime(< 1×109 Au-ions/cm2).The experiments were performed with the UV-Ramanand photoluminescence spectrometer (UV-laser: 244 nm)of Jobin Yvon Horiba. Calcite irradiated with 1×106Au-ions/cm2 (11.1 MeV/u) show distinct photolumines-cence with bands at about 520 and 545 nm (Fig. 1), whichmatches the greenish, yellowish color of the luminescencelight whereas unirradiated calcite crystals show only a mi-nor peak at 545 nm. When increasing the fluence to1×108 Au-ions/cm2, the amplitude of both peaks increases(Fig. 1). All spectra are taken with the following parame-ters: grate 300, objective 40×, accumulation 2×, hole 50.∗Work supported by BMBF Verbundprojekt 05K10VH1† Sebastian.Dedera@geow.uni-heidelberg.deExcitation (UV-laser: 244 nm) of the SIS-calcite also in-dicated the already known two bands with high amplitude(Fig. 2). In addition, a new peak at about 575 nm is ob-served.Summarizing the first results, UV-excitation combinedwith photoluminescence spectroscopy is sensitive enoughto detect crystal defects created by heavy ions (11.1 MeV/u197Au) at a fluence as low as 1×106 ions/cm2.So far Raman spectroscopy and detection with the UV-excitation (Laser: 244 nm) did not lead to any fluence-related change of the Raman bands.Figure 1: PL-Spectra of calcite crystals irradiated with1×106 and 1×108 Au-ions/cm2 (11.1 MeV/u). Spectraare not shifted, (detection time 20 s irradiated, 1 s non-irradiated).Figure 2: PL-Spectra of SIS-calcite crystal irradiated with1×1011 U-ions/cm2 (192 MeV/u). Strong luminescencedue to good noise/signal ratio (detection time 5 s).References[1] M. Gaft, L. Nagli, G. Panczer, G. Waychunas and N. Po-rat. ”The Nature of Unusual Luminescence in Natural CalciteCaCO3.” American Mineralogist 93, no. 1 (2008): 158-167.PNI-MF-02 GSI SCIENTIFIC REPORT 2013178 doi:10.15120/GR-2014-1-PNI-MF-02

New approach to investigate irradiated calcite crystals - UV Raman and Photoluminiscence with UV excitation

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New approach to investigate irradiated calcite crystals - UV Raman and Photoluminiscence with UV excitation

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