This paper discusses hadron energy reconstruction for the ATLAS barrel
prototype combined calorimeter (consisting of a lead-liquid argon
electromagnetic part and an iron-scintillator hadronic part) in the
framework of the non-parametrical method. The non-parametrical method
utilizes only the known e/h ratios and the electron calibration
constants and does not require the determination of any parameters by a
minimization technique. Thus, this technique lends itself to an easy use
in a first level trigger. The reconstructed mean values of the hadron
energies are within +/-1% of the true values and the fractional energy
resolution is [(58+/-3)%/rootE+(2.5+/-0.3)%]circle
plus(1.7+/-0.2)/E. The value of the e/h ratio obtained for the
electromagnetic compartment of the combined calorimeter is 1.74+/-0.04
and agrees with the prediction that e/h > 1.66 for this electromagnetic
calorimeter. Results of a study of the longitudinal hadronic shower
development are also presented. The data have been taken in the H8 beam
line of the CERN SPS using pions of energies from 10 to 300 GeV. (C)
2002 Elsevier Science B.V. All rights reserved