# State-of-the-Art Mobile Radiation Detection Systems for Different Scenarios
## 4 Mobile Radiation Detection Systems
### Radiation Detection and Gamma Spectrometry
#### 4.2.2 Airborne Survey
Following this project, [PERSON] et al. [141] explored different approaches to estimate the number of sources, intensity, and their location. It was concluded that the maximum likelihood algorithm provides the best results, and the application of a collimator into the radiation sensor improves the source localization; however, it has a negative impact on the payload and STN ratio. Future research is required on path planning for survey time optimization. To solve the lack of software and hardware specific for radioactive source detection, a CZT coupled to an UAV (multi-rotor) and a laser altimeter for precision height measure \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Name** & **Sensor Type** & \begin{tabular}{c} **Sensor Size** \\ **(cm\({}^{3}\))** \\ \end{tabular} & \begin{tabular}{c} **FWHM \% @** \\ **662 keV** \\ \end{tabular} & \begin{tabular}{c} **Energy** \\ **Range (keV)** \\ \end{tabular} & **Power Signal** & **Weight (g)** & \begin{tabular}{c} **Unit Size** \\ **(mm)** \\ \end{tabular} & **Price (€)** & **Ref.** \\ \hline \multirow{3}{*}{\begin{tabular}{c} GR-1 \\ (Kromek) \\ \end{tabular} } & \multirow{3}{*}{CZT} & \multirow{3}{*}{1} & \multirow{3}{*}{\(<\)2.5} & \multirow{3}{*}{20-300} & \multirow{3}{*}{\begin{tabular}{c} USB (250 \\ mW)/(USB/ \\ MCO) \\ \end{tabular} } & \multirow{3}{*}{60} & \multirow{3}{*}{25\(\times\) 25 \(\times\) 63} & \multirow{3}{*}{3000-9000} & [18; 113] \\  & & & & & & & \\ \hline \multirow{3}{*}{\(p\)spec (Ritec)} & \multirow{3}{*}{CZT} & \multirow{3}{*}{1} & 0.06 & \(<\)2 & \multirow{3}{*}{20-3000} & USB/Micro & 60 & 6500 (except \\  & & 1.6 & \(<\)3 & & USB & 70 & 4 cm\({}^{3}\) & [18; 112] \\  & & 4 & \(<\)4 & & 100 & & crystal) & \\ \hline \multirow{3}{*}{\begin{tabular}{c} MGS series \\ (MS) \\ \end{tabular} } & \multirow{3}{*}{CZT} & 0.06 & \(<\)1.5 & \multirow{3}{*}{30-3000} & \multirow{3}{*}{USB/USB,TTL} & \multirow{3}{*}{\(<\)50} & \multirow{3}{*}{64\(\times\) 25 \(\times\) 15} & [161] \\  & & & & & & & \\ \hline \multirow{3}{*}{\begin{tabular}{c} SIGMA \\ (Kromek) \\ \end{tabular} } & \multirow{3}{*}{CsI(Tl)} & 32.8 & \multirow{3}{*}{\(<\)7.2} & \multirow{3}{*}{\begin{tabular}{c} USB (250 \\  mW)/USB \\ \end{tabular} } & 300 & 35\(\times\) 35 \(\times\) 105 & 4000–5000 & [18; 162] \\  & & & & & & \\ \hline \multirow{3}{*}{\begin{tabular}{c} Rapix \\ (Crytur) \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} Timepix \\ (Silicon) \\ \end{tabular} } & \multirow{3}{*}{\
\begin{tabular}{c} Timepix \\ \(14.1\times 14.1\,\)mm \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} Ethernet (5 W) \\ / Wi-fi or \\ Ethernet \\ \end{tabular} } & 275 & 97\(\times\) 65 \(\times\) 35 & [163] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Selection of commercially off-the-shelf (COTS) lightweight spectrometers with potential for use in mobile platforms. ments was implemented, as well as a software to manage the communication and data was storage [165]. For example, depending on the signal latency, the RIMAspec software can commute between the available links (private radio networks, Wi-Fi, and 3G/4G) to ensure best data transmission to the ground station. Since the uncertainties arose mainly from the distance to the source and the low statistics, in the future, the CZT will be replaced by a higher efficiency 5.08 \(\times\) 5.08 (cm) NaI scintillator. In order to increase the situation awareness of the operator, a visuo-haptic augmented reality interface was proposed for the teleoperation of a multi-rotor equipped with a CZT detector for the localization of nuclear sources in outdoor environments [167]. To characterize the soils contaminated by \({}^{241}\)Am and \({}^{152}\)Eu (anthropogenic causes), [PERSON] et al. [168] proposed another compact and lightweight (180 g) gamma-ray spectrometer, a semiconductor CdTe detector with an active area of 25 mm\({}^{2}\) and a thickness of 1 mm, with a energy resolution <1.5% full width at half-maximum (FWHM) at 122 keV, coupled to a multi-rotor.