Context :

Aims : We present deep H.E.S.S .
observations of the supernova remnant ( SNR ) RX J1713.7 - 3946 .
Combining data of three years – from 2003 to 2005 – we obtain significantly increased statistics and energy coverage as compared to earlier 2003 & 2004 results .

Methods : The data are analysed separately for the different years .

Results : Very good agreement of the gamma-ray morphology and the differential spectra is found when comparing the three years .
The combined gamma-ray image of the 2004 and 2005 data reveals the morphology of RX J1713.7 - 3946 with unprecedented precision .
An angular resolution of 0.06 \degr is achieved , revealing the detailed structure of the remnant .
The combined spectrum of all three years extends over three orders of magnitude , with significant gamma-ray emission approaching 100 TeV .
The cumulative significance above 30 TeV is 4.8 \sigma , while for energies between 113 and 294 TeV an upper limit on the gamma-ray flux of 1.6 \times 10 ^ { -16 } ~ { } \mathrm { cm } ^ { -2 } ~ { } \mathrm { s } ^ { -1 } is obtained .

Conclusions : The energy coverage of the H.E.S.S .
data is presumably at the limit of present generation Cherenkov telescopes .
The measurement of significant gamma-ray emission beyond 30 TeV formally implies the existence of primary particles of at least that energy .
However , for realistic scenarios of very-high-energy gamma-ray production , the Inverse Compton scattering of very-high-energy electrons and \pi ^ { 0 } decay following inelastic proton-proton interactions , the measured gamma-ray energies imply that efficient acceleration of primary particles to energies exceeding 100 TeV is taking place in the shell of the SNR RX J1713.7 - 3946 .