## 3 Results  
The temperature drift curves for each shot were analysed offline, converting the radiation-induced temperature rise (measured in K) into a measure of the absorbed dose through the specific heat capacity of the absorber material, \(\mathrm{c_{g}}\). Calibration of the core thermistors was carried out at the NPL using a CTR3000 thermometer and PRT probe system, traceable to national standards allowing the bridge-out-of-balance voltage to be converted to the temperature in the thermistors. For every shot taken, the temperature rise resulting from the impinging proton beam was converted to the absorbed dose deposited in the calorimeter core. The data taken for the dose from each shot, in addition to the target and film parameters, are outlined in Table 1.  
Figure 9: Digitised RCF layer from which the deposited dose was integrated over the core area. The dimensions of the film are shown, along with an energy scale highlighting the dispersion of kinetic energy components identified through Monte Carlo simulation. Given the relatively low levels of dose encountered, thermistors T1, T2 and T3 showed remarkably good levels of consistency. For example, within shot 1, absorbed dose values of 2.018 Gy, 2.048 Gy and 2.035 Gy were found from core thermistors 1, 2 and 3, respectively. The uncertainty of the dose values found from the temperature rise in the SPGC core thermistors was estimated to be \(\sim\)12.7%. This analysis was performed through consideration of the fluctuation in temperature drift of the data acquisition and dose deposition over the sensitive area of the calorimeter. An upper and lower bound was set for the temperature drift curves pre- and post irradiation and the variation analysed. This is a conservative estimation taking into consideration only the systematic error of the measurement, as the statistics cannot be considered due to the low number of shots performed. It is important to note that the absorbed dose measurement with a calorimeter is independent of the pulse width, instead depending only on the amount of energy that is transferred to the system during irradiation. It is thus possible that different pulses may deposit exactly the same energy with the same corresponding absorbed dose. This represents a great advantage of calorimeters, which are dose-rate and/or dose-per-pulse independent, unlike ionisation chambers, which are routinely used in clinical dosimetry. The GaFchromic EBT3 film layers attached to the SPGC during each shot (see Figures 3 and 4) provided an additional measurement of the dose. From these measurements, it was found that the dose deposited on the RCF was greater than that retrieved from the calorimeter, as shown in Table 1. The greater RCF dose is a consequence of the energy spectrum of the laser-accelerated proton bunch (typically exponential, as per [11]), with lower proton energies present in higher proportions. From the LISE++ calculations mentioned previously, a proton energy of 12.1-12.2 MeV is needed to traverse both the film and graphite jacket layers, meaning that the dose contributions of energy components below this threshold will be absent from the absorbed dose measured in the calorimeter core. From these calculations, it is also estimated that 1.96 MeV protons are stopped in the initial RCF, with the remaining 10.24 MeV lost in the jacket. This dose decrease was further investigated through Monte Carlo simulation of the setup with the particle simulation toolkit TOPAS [46; 47]. Separate simulations were used to retrieve the dose within this initial jacket and film region, followed by that in the SPGC core, with a decrease in the absorbed dose of 49% indicated. These were performed using the entirety of the exponential energy spectrum. This clearly highlights the effect of the insulating jacket layer on the measured dose, outlining the minimum energy requirements needed from proton sources.