Contents lists available at ScienceDirect Applied Radiation and Isotopes journal homepage: www.elsevier.com/locate/apradiso Ti:Pt:Au:Ni thin-film CVD diamond sensor ability for charged particle detection Haruetai Kasiwattanawut a , Modeste Tchakoua Tchouaso a , Mark A. Prelas a,b, ⁎ a Nuclear Science and Engineering Institute, University of Missouri Columbia, MO 65211, United States b Electrical Engineering and Computer Science, University of Missouri-Columbia, MO 65211, United States HIGHLIGHTS • Development of a diamond sensor with reliable contacts using a new metallization formula, which can operate under high-pressure gas environment. • The metallization consists of Ti:Pt:Au:Ni with layer thicknesses of 50/5/20/150 nm, to produce Ohmic contacts. • Sensor used to determine if products from nuclear reactions are produced in the Ni-H LENR system. • Sensor calibration was performed using 239 Pu and 241 Am. • The energy resolution of the Ti: Pt:Au:Ni diamond sensor was determined to be 7.6% at 5.2 MeV of 239 Pu and 2.2% at 5.48 MeV of 241 Am. ARTICLE INFO Keywords: CVD diamond Charged particles Energy range Energy resolution, Ni-H LENR System ABSTRACT This work demonstrates the development of diamond sensors with reliable contacts using a new metallization formula, which can operate under high-pressure gas environment. The metallization was created using thin film layers of titanium, platinum, gold and nickel deposited on a single crystal electronic grade CVD diamond chip. The contacts were 2 mm in diameter with thickness of 50/5/20/150 nm of Ti:Pt:Au:Ni. The optimum operating voltage of the sensor was determined from the current-voltage measurements. The sensor was calibrated with 239 Pu and 241 Am alpha radiation sources at 300 V. The energy resolution of the Ti:Pt:Au:Ni diamond sensor was determined to be 7.6% at 5.2 MeV of 239 Pu and 2.2% at 5.48 MeV of 241 Am. The high-pressure gas loading environment under which this sensor was used is discussed. Specifically, experimental observations are de- scribed using hydrogen loading of nickel as a means of initiating low energy nuclear reactions. No neutrons, electrons, ions or other ionizing radiations were observed in these experiments. 1. Introduction Diamond technology has undergone continuous development and improvement since the 1980's (Collins, 1989; Herb et al., 1989; Imai and Fujimori, 1989). High quality diamond with state of the art con- tacts were produced by several groups (Fang et al., 1989; Planskoy, 1980; Prins, 1986). In the 1990s, the development of high purity electronic grade diamond by chemical vapor deposition (CVD) tech- nique for use in applications such as radiation detection was widely investigated. Progress led to the development of diamond radiation detectors for UV photons (Mainwood, 2000; Salvatori et al., 2002), x- rays (Bohon et al., 2010; Girolami et al., 2012; Kania et al., 1990), gammas (Bergonzo et al., 2003; Deleplanque et al., 1999), alphas (Schirru et al., 2014; Souw and Meilunas, 1997), and neutrons (Miller, 1966; Pillon et al., 2011). The interest in using diamond for radiation detection is due to its superior semiconducting properties such as its high-energy band gap, its ability to operate at high temperatures, its high mobility of free charges, and its radiation hardness. These prop- erties make diamond suitable for nuclear applications. Diamond has a band gap of 5.47 eV. It requires ~13.2 eV to create an electron-hole pair in high purity diamond and the average fraction of energy used in electron-hole pair production is about 44%. Charged particles are detected through the formation of electron-hole pairs generated within its energy band structure. The electron-hole pairs are swept by applying a voltage across the sensor, which is converted into an electric pulse. The dark current for a diamond sensor (bulk and surface current) is less than 1 pA/mm 2 for an electric field of 1 V μm -1 (Adam et al., 1999). As will be described, the new metal contact formulation on an electronic grade single crystal diamond wafer of Ti:Pt:Au:Ni makes an https://doi.org/10.1016/j.apradiso.2018.05.012 Received 27 October 2017; Received in revised form 26 April 2018; Accepted 13 May 2018 ⁎ Corresponding author at: Nuclear Science and Engineering Institute, University of Missouri Columbia, MO 65211, United States. E-mail address: prelasm@missouri.edu (M.A. Prelas). Applied Radiation and Isotopes 139 (2018) 181–186 0969-8043/ © 2018 Elsevier Ltd. All rights reserved. T