## 3 ELIMAIA Dosimetry Description
### Detectors for Relative and Absolute Dosimetry
#### 3.2.4 Irradiation Procedures  
The detectors for relative and absolute dosimetry described above will allow one to real-time monitor the beam and measure the dose per single shot, in order to provide a reliable characterization of the dosimetric parameters, necessary for multidisciplinary applications as, for instance, radiobiology experiments. Exploiting the possibility of easily changing the relative positions of the different detectors, shown in Section 3.1, a final irradiation configuration can be chosen according to the transported energy or to the specific user requirements. Once fixed, a preliminary beam characterization can be carried out using appropriate dosimetric detectors to determine the beam parameters, in terms of field size and beam range, also checking the transversal beam uniformity and its reproducibility.  
After this preliminary characterization and, possibly, a further beam transport optimization, the cross-calibration of the in-transmission ionization chamber can be done against the FC, in order to retrieve the calibration factor that will be necessary for subsequent sample irradiations. These are actually performed by replacing the FC with the sample irradiation system, which will be placed at the same position of the FC along the beam axis (Figure 13).  
Figure 12: (**a**) Picture of the ELIMAIA FC installed in target chamber; (**b**) Ion signal acquired by the FC at about 3 m from the target.  
The SIS is composed by a squared aluminum plane, physically connected to two stepping motors that control its movement in the X/Y directions with a total excursion of 400 mm and a resolution of 0.1 mm.  
Different plexiglass masks can be mounted on the aluminum plane. The masks are constituted by many housings, whose size and shape will depend on the samples to be irradiated.  
A second aluminum plane, thick enough to stop the most energetic protons, is mounted 5 cm away from the first one. This second plane is provided with a hole where additional collimators of different shapes and size can be mounted. The role of the second plane is basically to collimate the beam according to the user requirements and, at the same time, to shield the samples by the undesired radiation.  
The translating stages will allow one to place user samples at the same point where the absolute dosimetry is performed. A dedicated software will allow remote and automatic control of the system movements; it will generate a feedback signal in order to start/stop the shots sequence according to the specific amount of dose required per sample, which will correspond to a specific number of shots.  
Following the described approaches and after a preliminary tuning of the beam transport aiming to provide single shot doses of a few cGy, sample irradiations of the order of few Gy/min could be achieved, provided a laser repetition rate of about 1 Hz [31]. These are preliminary predictions, according to the Geant4 Monte Carlo code specially developed to simulate the ELIMED application line [42]. Indeed, the mentioned figures might be sensibly dependent on the laser-plasma source, both in terms of energy distribution and spatial profile, and also on the user requirements in terms of required beam size and spatial homogeneity at the sample.  
The versatility of the ELIMAIA beamline and its installed equipment will allow it to deliver controllable and stable beams with accurately measured doses per shot, in the perspective of experimental activities aiming to demonstrate the feasibility of laser-driven beams for biomedical and multidisciplinary applications.  
Figure 13: 3D model rendering of the sample irradiation system.