As a second step we plan to determine the response function to monoenergetic lines in a special run with several pionic transitions in the energy region of interest. These lines should not be influenced by strong interaction or broadening by not resolved electron screening or any kind of Doppler effect. Therefore only transitions of exotic atoms formed with monoatomic gases with can be used. Those do not exhibit Coulomb explosion during their formation and they have a high and well known degree of ionization at pressures below . Strong interaction broadening can be avoided for transitions high enough in the cascade. A list of appropriate transitions also including non-monoatomic gases is given in Table 9 for pionic atoms. Muonic atoms except muonic hydrogen should not be considered because of the one order of magnitude lower stop rate. It should be noted that the strong interaction width is only of about for and for [82,83,84]. Molecular gases like and are included because at present the line form of these atoms is being studied intensively and will be much better known at the time of the proposal of this experiment. is included as it will be used in the form of for which a small Coulomb explosion  energy can be expected.
A dedicated run is foreseen with a special pion stop mode. In this case the pion stop rate can be further optimized as the simultaneous measurement of muonic transitions is not required. The expected rates for a mixed (target are given in chapter 3.6. The numbers for independent single gas measurements are a factor of 2 higher.