## 3 Results
For the irradiation in which the calorimeter was withdrawn from the irradiation point, the online analysis software was monitored for any potential signal disruption that may occur as a result of EMP generation. Such distortion would affect the resolution of the system and, hence, the final dose value obtained from the temperature rise in the core. This initial concern was alleviated through the very good signal-noise ratio evident in the temperature drift signals. This is further supported by the radiation-induced temperature \begin{table}
\begin{tabular}{c c c c c} \hline  & **Shot 1** & **Shot 2** & **Shot 3** & **Shot 4** \\ \hline Target Material & 15 \(\mu\)m Au & 1 \(\mu\)m CH plastic & 15 \(\mu\)m Au & 15 \(\mu\)m Au + lead absorber \\ Mean dose to core & 2.03 & 1.05 & 1.65 & 0.41 \\ Standard deviation (Gy) & 0.0152 & 0.0075 & 0.0179 & 0.0046 \\ SDOM (\%) & 0.4319 & 0.4121 & 0.6254 & 0.6565 \\ RCF dose (Gy) & 3.53 & 2.75 & 2.99 & 1.00 \\ Dose decrease (RCF-SPGC, \%) & 42.3 & 61.9 & 44.8 & 59.0 \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of the mean values of absorbed dose measured with the three correctly operating thermistors within the small-body portable graphite calorimeter using the VULCAN-PW laser system at CLF, calculated from the radiation-induced temperature rise in the core. The data from core thermistor 4 are omitted as they were not consistent with the other 3 due to an issue with a poor electrical connection within the measurement electronics. For comparison, the dose deposited on the RCF placed on the front face of the SPGC for each shot is also included. signals shown in Figure 10, detected with the calorimeter placed in the beamline. When removed from the irradiation point, no change in the background drift of the calorimeter signal was observed. Table 1 presents the values of the absorbed dose to the core measured with the calorimeter in the different shots. The variations observed are due to the deposited dose being dependent to some extent on the stability of the laser parameters (which will affect the proton spectrum), as well as the characteristics of the target from which the beam is accelerated. The laser instability contributes to this effect to a lesser effect than that of the target material, which plays a major role particularly within the target normal sheath acceleration (TNSA) mechanism [11]. From the data displayed in Table 1, the higher dose values were measured in shots 1 and 3, where the TNSA protons were accelerated from a 15 \(\upmu\)m thick gold target. With respect to these, shot 2 (using a 1 \(\upmu\)m CH target) displays a reduced dose in the core thermistors. This is evident from the data outlined in Figure 11, which was taken from an analysis of the dose profile in the respective RCF layers. The differences in the dose profiles shown in Figure 11 are indicative of a less-efficient acceleration from the thinner CH target, giving a lower recorded measurement for the shot  
Figure 11: Dose profiles for shots 1 and 2 employing gold (15 \(\upmu\)m Au) and plastic (1 \(\upmu\)m CH), respectively. The thinner nature and less-effective sheath acceleration in the CH likely lead to the reduced dose. Figure 10: Temperature drift curves for the core thermistors used in the determination of the absorbed dose for the first laser shot. An excellent signal–noise ratio is apparent, indicating the absence of electronic distortion deriving from effects such as the EMP generation in the target chamber. The different colours simply indicate that the temperature drift curves shown in the relative plots have been taken from different thermistors (1, 2, 3) in the calorimeter core. in which this target was used. Acceleration from this plastic target (shot 2 of Table 1) is less efficient than the others as the integrity of the rear surface of this thin target was not likely preserved, which has been shown to inhibit the effectiveness of acceleration for the TNSA regime [12; 13].