Rate estimates are based on extensive tracking simulations and data from a feasibility study at the channel carried out with the new cyclotron trap (see Figure 6). The rates in Table 6 are given for a target gas pressure of and at room temperature on the basis of the following assumptions:
The pressure dependence of the rates urges to perform the experiment at higher pressures i.e. working with a cryogenic target. Therefore the experiment will start with an investigation of the bar region first and continue with lower pressures in a second step with a well tuned apparatus at the lowest feasible pressure. The rates of between 50 and 100 entries/h is sufficient to collect several X-ray events in total in a three weeks measuring time. It should be recalled that about events are sufficient to determine the shift with an accuracy of and also open the possibility to determine the width on the level. The values for nitrogen and oxygen are given for a set-up optimized to pion stops. The experiment with a combination of nitrogen and oxygen gas is highly valuable as it allows for a direct check of the two-crystal method.
The numbers are also representative for other measurements like pionic Ne or C. For these gases as well as for nitrogen and oxygen the maximum tolerable partial pressure is at about . This limitation is given by the self absorption of the low energy X-rays in the target gas.