## 1 Introduction  
Radiation can be broadly divided into two categories: uncharged radiation, including X-rays, gamma rays, and neutrons; charged radiation, including electrons, positrons (beta particles), and alpha particles [1]. Radiation sensors are able to transform the energy lost by an incident particle into an electrical signal, which is then processed by electronic techniques. Metal oxides (MOs) are among the most commonly used materials for advanced applications due to their availability, low cost, simple synthesis procedures and flexible morphology and composition [2]. Accordingly, many researchers have used these materials for different applications, ranging from catalysts [3] to sensors [4; 5; 6; 7].  
In particular, they can be used for high-energy radiation sensors. In fact, the radiations with a high energy like gamma rays and X-rays can alter the concentration of oxygen vacancies and also create point defects and other structural defects in MOs [8]. Therefore, metal oxides can be used for the detection of high-energy radiation [9].  
Today, low-cost radiation sensors based on MOs operating at room temperature are sought after for applications in science, industry, medicine and security [10]. Additionally, unpredictable accidents may occur during the storage or transportation of radioactive materials, which highlights the needs for metal oxide radiation sensors.  
A radiation sensor should have a high sensitivity, a linear performance and an on-line response, low levels of noise and high reliability [11]. Based on the above criteria, a number of MOs were suggested for gamma ray sensing [12; 13]. For example, it has been reported that the electrical properties of TeO\({}_{2}\) and many other MOs greatly change after gamma ray bombardment [14]. Although X-rays can also affect the structural properties of MOs, there are few reports about X-ray radiation sensors based on MOs in the literature [15; 16; 17].  
SnO\({}_{2}\) is a well-known n-type semiconducting metal oxide (Eg = 3.8 eV). It has a high mobility of electrons (160 cm\({}^{2}\)/Vs), high physical and chemical stability, a high availability and a low price [18]. Therefore, it has been used in many applications, including gas sensors [19], lithium ion batteries [20], photodetectors [21] and electrodes [22]. Therefore, different methods, such as the vapor-liquid-solid (VLS) technique [23; 24], colloidal synthesis [25], chemical vapor deposition [26; 27] and hydrothermal [28] have been used for the preparation of SnO\({}_{2}\) nanowires (NWs). Among them, the VLS method has advantages, such as simplicity, low price and the possibility of control over the SnO\({}_{2}\) NWs. Generally, the length of NWs depends on the growth time, and the NW's diameter is determined by the size of the metal catalyst droplets [29].  
In this study, we prepared networked SnO\({}_{2}\) NWs and measured their capability to detect X-ray radiation at room temperature. Although networked NWs are very common for gas sensing studies [30; 31], there is no report on their X-ray sensing capabilities. To the best of our knowledge, this is the first study reporting X-ray radiation sensing using networked SnO\({}_{2}\) NWs. From a sensing response and performance standpoint, networked NWs sensors are potential candidates for radiation sensors because their carrier lifetime is enhanced significantly due to the reduction in defect density on the surface passivated NWs [32]. The results obtained demonstrate the effective sensing capability of SnO\({}_{2}\) NWs as X-ray sensors. The sensing mechanism is explained in detail.