Radiation degradation of Si ion detectors becomes critical for the experiments at new facilities giving the beam intensity increase up to 10^5 times. The study is focused on the impact of heavily damaged Bragg peak region (BPR) at the ion range end on the bulk current of Si sensors irradiated with 53.4 MeV ^40Ar ions in the fluence range (1 ‒ 4)x10^9 ion/cm^2. It is shown that taking into account only the generation current component is insufficient to explain the experimental I-V curves. Simulating I-V characteristics and the electric field profiles demonstrated arising of a built-in junction in the BPR, which controls hole diffusion at voltages below full depletion voltage. Contribution of this component to the total diode current enabled the agreement between experimental and simulated I-V curves.

The investigation is focused on the simulation of the I-V characteristics of Si p+-n-n+ diodes irradiated with medium-energy 40Ar ions whose range is less than the detector thickness. The characteristics were simulated by considering the distribution of the current generating defects related to the profile of primary vacancies with a sharply rising density at the end of the ion track, which was defined by using the TRIM software. The defects involved in the simulation were two radiation-induced acceptors, the one positioned at EC -0.42 eV and the other in the lower half of the bandgap at EC - 0.65 eV, responsible for the bulk current generation and the electric field distribution, respectively. With the adjusted characteristics of the defects, I-V characteristics in the fluence range (1-4)x109 cm-2 demonstrated a quantitative agreement with the experimental curves and a strict proportionality of the maximum current to the fluence. The electric field evolution with ion fluence was calculated and discussed as information complementary to the I-V data.

The presented paper is focused around radiation damage of silicon material under the different ions irradiation. The ion total energy range is 0.7 GeV for 7 Li to 208 GeV for 208 Pb. The results of TRIM modeling for the set of six ions are presented. The extracted information about vacancy production allows making first assumptions of the Si degradation dependence on mass and energy of the incident ion.

The investigation is focused on the defects in silicon p + -n-n + detectors irradiated with the 53.4 MeV 40 Ar ions, which generate a nonuniform defect distribution including a heavily damaged region inside the Bragg peak. The dependences of the bulk generation current and of the capacitance on bias voltage and the spectra of radiation-induced defects demonstrate new features: a step in the current rise, a region with a practically constant capacitance, and abnormal dependence of the peak amplitudes of vacancy-related defects on fluence. The changes of the DLTS spectra are assigned to the influence of silicon properties inside the Bragg peak region acting as a highly compensated insulating layer.

The presented study is focused around the TRIM program issues and its applications for prediction of silicon detectors degradation under heavy ions of 40Ar. Results of the simulations of low-energy ion (53.4 MeV) and high-energy ion (1.62 GeV) irradiation are demonstrated. Experimental data for silicon p+-n-n+ detectors irradiated by the low energy are also presented. Reliability of TRIM simulations application for studying silicon detectors degradation under heavy ion irradiation is discussed.

Silicon detectors irradiated by Ar-40 ions with the energy of 1.62 GeV were studied with the goal to find the parameters of radiation damage induced by ions. The measurements of the I-V characteristics, temperature dependences of the detector bulk current, deep level spectra and current pulse response were carried out for detectors irradiated within the fluence range 5 x 10(10)-2.3 x 10(13) ion/cm(2) and the obtained results were compared with the corresponding data for detectors irradiated by 23 GeV protons. It is shown that the processes of defect introduction by ions and overall radiation damage are similar to those induced by 23 GeV protons, while the introduction rates of radiation defects and current generation centers are about ten times higher for irradiation by Ar-40 ions. The fact that these processes have much in common gives grounds to use the physical models and characteristic parametrization such as those developed earlier for detectors irradiated by protons and neutrons to build the long-term scenario of Si detector operation in the Time-Of-Flight diagnostic system of Super FRagment Separator designed at GSI for the future Facility for Antiproton and Ion Research, FAIR.

This study focuses on evaluating the properties of voltage termination structure (VTS) with multiple guard rings in n(+)-p-p(+) silicon detectors with Al2O3 field isolation films processed by Atomic Layer Deposition (ALD) method. The dependences of the ring potential over the guard rings with respect to bias voltage were studied experimentally and compared with the results of simulations using negative charge Q(f) in Al2O3 films as a parameter. The agreement of the experimental and calculated punch-through voltages switching the ring operation verified that the punch-through model built for the p(+) -n-n(+) detectors passivated with positively charged SiO2 layers is also applicable for the n(+) -p-p(+) detectors with Al2O3 field isolator with negative charge polarity. The results indicated an efficient potential distribution over the VTS rings. The amount of the oxide charge was shown to be an essential parameter for the detector performance. From the comparison of the experimental data and simulations for Si detector with the used design and processing technology, Q(f) of -(4-7) x 10(11) cm(-2) was found to be the value explaining the properties of VTS in the detector under study. The simulations showed that Q(f) of -7 x 10(11) cm(-2) is an upper limit critical for the appearance of high electric field regions in the VTS. The increase in the silicon resistivity to 20 k Omega cm was found to be an efficient way to reduce the electric field below the value initiating the carrier avalanche multiplication.

The full-size prototypes of large-area silicon detectors for the Time-Of-Flight (TOF) diagnostics of heavy ions were tested with Xe-132 (600MeV/u) beam. The obtained time resolution of the prototypes was about 13 ps, which satisfied the requirements of diagnostics for the Super Fragment Separator (Super-FRS) that is under development at GSI, Darmstadt, Germany. The irradiation effect on the timing properties of silicon detectors was studied with super-fast silicon pad detectors with a rise time of 190 ps. It was shown that the changes in the rise time of the leading edge of the detector current response to Ar-40 ions (40.5MeV/u) were negligible up to the fluence of 2x10(11) ion/cm(2) expected after one year of Super-FRS operation. This result confirms the model of the leading edge current pulse formation via a flow of the polarization current in dense tracks of heavy ions and shows the perspectives for application of silicon detectors for the TOF diagnostics of intensive heavy-ion beams.