Experimental and theoretical studies of one-electron capture in collisions of He 2+ ions with H 2 O molecules have been carried out in the range 0.025-12 keV amu −1 corresponding to typical solar wind velocities of 70-1523 km s −1 . Translational energy spectroscopy ͑TES͒, photon emission spectroscopy ͑PES͒, and fragment ion spectroscopy were employed to identify and quantify the collision mechanisms involved. Cross sections for selective single electron capture into n = 1, 2, and 3 states of the He + ion were obtained using TES while PES provided cross sections for capture into the He + ͑2p͒ and He + ͑3p͒ states. Our model calculations show that He + ͑n =2͒ and He + ͑n =3͒ formation proceeds via a single-electron process governed by the nucleus-electron interaction. In contrast, the He + ͑1s͒ formation mechanism involves an exothermic two-electron process driven by the electron-electron interaction, where the potential energy released by the electron capture is used to remove a second electron thereby resulting in fragmentation of the H 2 O molecule. This process is found to become increasingly important as the collision energy decreases. The experimental cross sections are found to be in reasonable agreement with cross sections calculated using the Demkov and Landau-Zener models.

A first comprehensive study is presented on natural radionuclide activity concentrations in surface soils in different divisions of Tafila city. The natural radioactivity of 238 U, 232Th and 40 K is determined using gamma spectroscopy. The soil activity concentrations ranged from 1.8 to 76.

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A high natural radiation zone was investigated for the first time in Afra hot springs of Jordan. The radiation levels were measured using a portable Geiger-Muller counter and an Na(Tl) detector. The measured absorbed dose rates in air ranged from 10 to 1800 nGy h(-1), suggesting that the concentration of natural radioactive materials is very high compared with their normal abundance in crustal rocks. A single high-radiation zone was also found in a nearby area where a gamma radiation dose rate of 4.0 mGy h(-1) was measured. On the basis of this measurement, the area was marked as a high-radiation zone. This region is far from tourist areas and not easily reached. No intervention measures are needed to protect people because the spa area is not well inhabited, having only daily visitors (average frequency of 10 days per year per individual). The dose received by workers in the spa area should be considered and the worker should be monitored by personal radiation dosimeters, such as thermoluminescent dosimeters.

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