1. The presence of the South Pole Air Shower Experiment (SPASE) on the surface provides a set of externally tagged muon bundles that can be measured by AMANDA. Such measurements allow a study of the response of AMANDA that is complementary to studies of the deep detector with atmospheric muons and neutrinos, internal calibration sources and Monte Carlo simulations. The possibility of independent confirmation of the absolute pointing of the neutrino telescope with a surface array is a unique advantage of AMANDA. Method Determine direction of each event at surface with SPASE Compare the direction determined by AMANDA Measure response of each AMANDA OM to muon bundles as a function of impact parameter as determined by SPASE References E. Andres et al., Nature 410 (22 March 2001) J. Beaman et al., Phys. Rev. D48:4495 (1993) J.E. Dickinson et al., Nucl. Instr. Meth. A440:95 (2000) P.B. Price, et al., Geophys. Res. Lett. 27:2129 (2000) N.J.T. Smith et al., Nucl. Instr. Meth. A276:622 (1989) J. van Stekelenborg et al., Phys. Rev. D48:4504 (1993) Muon survey is performed by examining the distribution of signals in each OM as a function of impact parameter of the muon bundle as determined by the direction assigned to each coincident event by the surface detector. Muon survey plots show the zenith and azimuth of each AMANDA-B10 module as seen by SPASE-1 and SPASE-2. The 10 strings are clearly distinguishable, with the bottom of each string at small zenith angles. The muon survey confirms the absolute positions of the OMs as determined by drill logging plus laser calibration to within 0.5 o (~3m absolute). The corresponding confirmation of the absolute pointing of the telescope is ~1.5 o. AMANDA-B10 seen from SPASE-2 AMANDA-B10 seen from SPASE-1 X. Bai 1, R. Engel 1, T.K. Gaisser 1, J.A. Hinton 2, A. Karle 3, M. Kowalski 4, D. Martello 5, T. Miller 6, K. Rawlins 3, K. Rochester 2, G.M. Spiczak 1, Todor Stanev 1, S. Tilav 7, A.A. Watson 2 and the AMANDA Collaboration 1 Bartol Research Institute, Univ. of Delaware; 2 Dept. of Physics, Univ. of Leeds; 3 Dept. Of Physics, Univ. of Wisconsin, Madison; 4 DESY-Zeuthen; 5 INFN, Lecce; 6 APL; 7 NAPL, Oxford Table of Shower Properties S 30 E 0 (PeV) (p) (Fe) (p)(Fe) -------------------------------------- 0.3 7 3 4 7 1 25 121025 3 100 602565 Muons with energy of 350 GeV at the surface reach the top of AMANDA, while muons with 550 GeV can penetrate through it. About half the muons in the bundle range out inside AMANDA Size of muon bundles at AMANDA is comparable to the string spacing The difference between muon bundles and single, neutrino-induced muons must be taken into account when using SPASE-AMANDA coincidences to check AMANDA track reconstruction For large events the lateral distribution of the signal generated by the muon bundle can be measured by AMANDA and used in coincidence with the surface signals as a measure of primary cosmic ray composition in the region of the knee of the spectrum. Lateral distribution of 6 events as measured by AMANDA-B10. The corresponding energies are in the PeV range as indicated by S 30. Integral lateral distributions of muons at the depth of AMANDA for simulated proton (dashed) and iron (dotted) showers. The plot shows the average number of muons at distances larger that a given radius (R) for 4 bins of shower size. S 30 is the particle density on the surface at 30 m core distance. Hit probability per OM as a function of impact parameter is fit by an exponential. The attenuation length determined in this way is a convolution of the attenuation length of the ice and the angular resolution of SPASE. It is therefore larger than the intrinsic effective attenuation length of the ice. Depth dependence determined by this method provides an independent look at ice properties. Depths of relatively short attenuation lengths correspond to dust layers as in Price et al. (2000). SPASE-1 (Smith et al., 1989; Beaman et al., 1993; van Stekelenborg et al., 1993) operated from 1988 through 1997 SPASE-2 (Dickinson et al., 2000) began operation in 1996 1997 unique for stereo view of AMANDA-B10 (Andres et al., 2001) from surface Map shows the locations of SPASE-1 and SPASE-2 relative to AMANDA-B10 strings at the surface. The origin of the coordinate system is near the center of B10. The positive Y-direction is grid-north. Azimuth is measured counterclockwise from grid-east. Thus the center of SPASE-2 is at 247 o and the center of SPASE 1 at 327 o. XXVII ICRC, 7-15 August 2001, Hamburg, Germany Poster Session HE2.01 Poster Board Number HE208