P.W. Cattaneog, A. Argana, p, t, F. Boffellig, A. Bulgarellie, B. Buonomou, A.W. Chenc, d, F. D’Ammandov, L. Foggettad, 1, T. Froyslandb, d, F. Fuschinoe, M. Gallih, F. Gianottie, A. Giulianic, F. Longof, M. Marisaldie, G. Mazzitelliu, A. Pellizzonir, M. Prestl, G. Pucellam, L. Quintieriu, A. Rappoldig, M. Tavania, b, M. Trifoglioe, A. Troisr, P. Valentei, E. Vallazzaf, S. Vercellones, A. Zambrac, G. Barbiellinif, P. Caraveoc, V. Coccoa, E. Costaa, G. De Parisa, E. Del Montea, G. Di Coccoe, I Donnarummaa, Y. Evangelistaa, M. Ferocia, A. Ferrarid, q, M. Fiorinic, C. Labantie, I. Lapshova, F. Lazzarottoa, P. Liparii, M. Mastropietroj, S. Mereghettic, E. Morellie, E. Morettif, A. Morsellik, L. Pacciania, F. Perottic, G. Pianoa, b, k, P. Picozzab, k, M. Pilial, G. Porrovecchioa, M. Rapisardam, A. Rubinia, S. Sabatinia, b,P. Soffittaa, E. Strianib, k, V. Vittorinia, b, D. Zanelloi, S. Colafrancescon, P. Giommin, C. Pittorin, P. Santolamazzan, F. Verrecchian, L. Salottio
a INAF/IASF-Roma, I-00133 Roma, Italy b Dip. di Fisica, Univ. Tor Vergata, I-00133 Roma, Italy c INAF/IASF-Milano, I-20133 Milano, Italy d CIFS-Torino, I-10133 Torino, Italy e INAF/IASF-Bologna, I-40129 Bologna, Italy f INFN Trieste, I-34127 Trieste, Italy g INFN-Pavia, I-27100 Pavia, Italy h ENEA-Bologna, I-40129 Bologna, Italy i INFN-Roma La Sapienza, I-00185 Roma, Italy j CNR-IMIP, Roma, Italy k INFN Roma Tor Vergata, I-00133 Roma, Italy l Dip. di Fisica, Univ. Dell’Insubria, I-22100 Como, Italy m ENEA Frascati, I-00044 Frascati (Roma), Italy n ASI Science Data Center, I-00044 Frascati (Roma), Italy o Agenzia Spaziale Italiana, I-00198 Roma, Italy p Osservatorio Astronomico di Trieste, Trieste, Italy q Dip. Fisica, Universitá di Torino, Torino, Italy r INAF-Osservatorio Astronomico di Cagliari, localita’ Poggio dei Pini, strada 54, I-09012 Capoterra, Italy s INAF-IASF Palermo, Via Ugo La Malfa 153, I-90146 Palermo, Italy t Dip. Fisica Univ. di Trieste, I-34127 Trieste, Italy u INFN Lab. Naz. di Frascati, I-00044 Frascati (Roma), Italy v INAF-IRA Bologna, Via Gobetti 101, I-40129 Bologna, Italy
Received 25 November 2011. Revised 16 January 2012. Accepted 19 January 2012. Available online 27 January 2012.
At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a γ-ray beam to validate the simulation used to calculate the energy response function and the effective area versus the energy and the direction of the γ rays. A tagged γ-ray beam line was designed at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali of Frascati (LNF), based on an electron beam generating γ-rays through bremsstrahlung in a position-sensitive target. The γ-ray energy is deduced by difference with the post-bremsstrahlung electron energy  and . The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS system as tagged photon beam requires understanding the efficiency of γ-ray tagging, the probability of fake tagging, the energy resolution and the relation of the PTS hit position versus the γ-ray energy. This paper describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation.