## 3 Expected Production Rates  
By placing the CERN-MEDICIS target behind an ISOLDE target, we improved the target design to match the isotope production yields of ISOLDE. However, since the beam is scattered after the primary target, the amount of the secondary target material has to be increased to make up for the loss of protons (Figures 2 and 3), by increasing CERN-MEDICIS's target density and diameter. The optimal volume was defined as 196 cm\({}^{3}\), approximately four times ISOLDE's core volume. The densities were also increased. The production rates obtained with CERN-MEDICIS were first studied under ISOLDE and HIE-ISOLDE proton beam characteristics. FLUKA [3, 4], a fully integrated particle physics Monte Carlo simulation software package, was used to simulate the in-target yields of the relevant isotopes and combined with experimental extracted yields observed at ISOLDE [5] to obtain the estimates shown in Table 2. Extrapolation is also provided for a possible future upgrade of the proton beam \begin{table}
\begin{tabular}{l l l} \hline
**Operation Phase** & **Milestone** & **Date** \\ \hline Phase I & Commissioning: no beam & end 2015 \\ Phase II & Commissioning with beam and light targets to gain operational experience & 2016 \\ Phase II B & Isotope production with light targets & middle 2016 \\ Phase III & Extending to heavy targets up to tantalum & end 2016 \\ Phase IV & Collection of short-lived alpha emitters (e.g., 149 Tb) & 2017 \\ Phase IV B & Operation with lasers & 2018 \\ Phase V & Operation with uranium targets/possible proton beam upgrade & 2018 \\ \hline \end{tabular}
\end{table} 
Table 3: Tentative planning of the construction and staged start-up of the CERN-MEDICIS facility. Figure 2: CERN-MEDICIS sample/target characteristics. characteristics, reaching an average of 6 \(\upmu\)A and 2 GeV of proton energy. In that case, provided the isotope separation efficiencies are further improved, gigabecquerel production levels for a number of relevant isotopes will become available, with a notable 10 GBq \({}^{149}\)Tb batch production scale, which could take place on a daily basis during the CERN accelerator complex operation. Our simulated in-target production results are computed for a homogeneous target material. For ISOL (Isotope mass Separation OnLine) isotope extraction, the microstructure of the target is optimized to maximize the extraction efficiency and selectivity during the mass separation process [6]. For this last step, the experience already gained at ISOLDE during the past 40 years is of utmost importance, and possible future developments are expected to provide production gains. The diagram in Figure 3 illustrates the cycle for a CERN-MEDICIS target from its preparation until the isotope extraction, purification and final shipping:  
The isotope extraction is preceded by an off-line separation performed in the CERN-MEDICIS bunker, where a dedicated target station equipped with services and an electrostatic acceleration stage will accelerate the nuclei before entering a dipole magnet. There, the radioactive ion beams are deflected in arcs of different radii according to their masses. A selective window is used to filter out the unwanted beams. The isotope mass separator in Figure 4, which will be transferred from the Centre de Ressources du Cyclotron (CRC) Louvain La Neuve/KU Leuven is equipped with a beam switchyard to direct three beams in parallel by means of a set of slits and electrostatic deflectors. The advantage of this feature in the foreseen collection process becomes evident: different isotopes of the same chemical element can be collected, for instance \({}^{149/152/155}\)Tb, providing possible theranostic combinations or extending further to different elements collected from the same target. The isotopes will be implanted in thin metallic foils, in polymeric supports coated with salt layers or directly in ice  
Figure 3: The MEDICIS cycle. * The figure is reprinted with permission from [7]. samples.