TY - JOUR
T1 - LIBS-spectroscopy for monitoring and control of the laser cleaning process of stone and medieval glass
AU - Klein, Stefan
AU - Hildenhagen, Jens
AU - Dickmann, Klaus
AU - Stratoudaki, T.
AU - Zafiropulos, Vassilis
PY - 2000/8/1
Y1 - 2000/8/1
N2 - On-line monitoring or even closed-loop control is necessary to avoid over-cleaning in case the ablation process is not self-limiting. Therefore, the laser-induced breakdown spectroscopy (LIBS) was used. Basic investigations were carried out on original sandstone samples (Elbsandstein) with strong encrustations as well as medieval stained glass samples (13th century from Cologne Cathedral). The spectroscopic study has shown that the plasma emission can be used for determination of the elemental composition of the ablated material. The plasma was initiated by 248-nm pulses of an KrF-excimer laser (30 ns FWHM). For the spectroscopic analysis, a grating spectrograph in combination with an optical multichannel analyser was used. For the glass and stone samples we obtained a continual alteration of the LIBS spectrum (vanishing of peaks and generating of new element peaks) during the removal process. Thus, certain element peaks can be used to distinguish between encrustation layer and valuable underlying material. To show the potential of LIBS we designed an experimental laser cleaning set-up including closed-loop LIBS control and demonstrated successful automatic cleaning of an original glass fragment.
AB - On-line monitoring or even closed-loop control is necessary to avoid over-cleaning in case the ablation process is not self-limiting. Therefore, the laser-induced breakdown spectroscopy (LIBS) was used. Basic investigations were carried out on original sandstone samples (Elbsandstein) with strong encrustations as well as medieval stained glass samples (13th century from Cologne Cathedral). The spectroscopic study has shown that the plasma emission can be used for determination of the elemental composition of the ablated material. The plasma was initiated by 248-nm pulses of an KrF-excimer laser (30 ns FWHM). For the spectroscopic analysis, a grating spectrograph in combination with an optical multichannel analyser was used. For the glass and stone samples we obtained a continual alteration of the LIBS spectrum (vanishing of peaks and generating of new element peaks) during the removal process. Thus, certain element peaks can be used to distinguish between encrustation layer and valuable underlying material. To show the potential of LIBS we designed an experimental laser cleaning set-up including closed-loop LIBS control and demonstrated successful automatic cleaning of an original glass fragment.
KW - laser cleaning
KW - LIBS
KW - medieval glass
KW - online monitoring
KW - sandstone
KW - laser induced breakdown spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=0034239115&partnerID=8YFLogxK
U2 - 10.1016/S1296-2074(00)00173-4
DO - 10.1016/S1296-2074(00)00173-4
M3 - Article
AN - SCOPUS:0034239115
VL - 1
SP - S287-S292
JO - Journal of Cultural Heritage
JF - Journal of Cultural Heritage
SN - 1296-2074
ER -