A prototype Silicon-Tungsten electromagnetic calorimeter (ECAL) for an International Linear Collider (ILC) detector was installed and tested during summer and autumn 2006 at CERN. The detector had 6480 silicon pads of dimension 1×1 cm 2 . Data were collected with electron beams in the energy range 6 to 45 GeV. The analysis described in this paper focuses on electromagnetic shower reconstruction and characterises the ECAL response to electrons in terms of energy resolution and linearity. The detector is linear to within approximately the 1% level and has a relative energy resolution of (16.6 ± 0.1)/ E(GeV) ⊕ 1.1 ± 0.1 (%). The spatial uniformity and the time stability of the ECAL are also addressed.

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Passage of ionizing radiation into the biological medium plays an important role in a variety of chemical modifications, directly or indirectly of the four DNA bases. However, up to now proton collisions on DNA bases remain experimentally approached and a theoretical model for total cross section, stopping cross section and Bragg peak calculation are poorly characterized. In this current work, we restricted our study on the interaction of energetic ion proton beams with DNA base adenine (C5H5N5). The total cross section produced by high energy impact of protons are here analytically investigated via a novel model combining two methods-the Rudd semi-empirical formulas to calculate the ionization and the analytic method based on the similitude between the electron energy loss in adenine and liquid water to calculate the excitation and charge-transfer-these cross sections used to describe the total stopping cross section of adenine molecule by protons including the nuclear stopping powers. We give in this work an estimation of the Bragg peak profile and position with impact energies ranging from 1 to 20 MeV/amu. The results are compared to the available experimental, theoretical and Monte-Carlo results, and reasonable agreements are generally observed especially for the ionization. The proposed method is useful as an alternative to traditional approaches, and is useful for studies of various radiation effects in other biological material.