Author(s): A. Abdo A., Ballet J., Bédérède D., Bogaert G., Bourgeois P., Bruel P., M. Casandjian J., Chipaux R., Cohen-Tanugi J., Dumora D., Farnier C., Ferreira O., Fleury P., Giebels B., A. Grenier I., Grondin M.-H., Guillemot L., Guiriec Sylvain, Knodlseder J., Lavalley-fouquet Claudia, Lemoine-Goumard M., Lott B., Nuss E., Parent D., Pelassa V., Piron F., Reposeur T., Sanchez D., A. Smith D., Starck J.-L.
(Article) Published:
Astroparticle Physics, vol. 32 p.193-219 (2009)
Links openAccess full text : 
Ref HAL: in2p3-00379324_v1
Ref Arxiv: 0904.2226
DOI: 10.1016/j.astropartphys.2009.08.002
Ref. & Cit.: NASA ADS
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116 citations
Abstract:
The Large Area Telescope (LAT) on--board the Fermi Gamma ray Space Telescope began its on--orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.
Comments: 60 pages, 34 figures, submitted to Astroparticle Physics