Narrow Results

The effect of high energy electron irradiation on the microstructure and thermal properties of natural rubber (NR) filled with different fillers at different concentrations are studied. The samples are irradiated with 8 MeV electron beam to a total dose of 100 KGy. The change in free volume size and specific heat due to addition of fillers and irradiation are studied using positron annihilation lifetime spectroscopy (PALS) and differential scanning calorimetry (DSC) respectively. The Positron lifetime spectra are de-convoluted into two components. The longer lived component $({\tau }_{\mathrm{\text{o}}-\mathrm{\text{Ps}}})$ signifies the pick-off annihilation of ortho-positronium (o-Ps) at free volume site which may be related to the radius of the free volume holes. It is observed that the specific heat $(C_p)$ and free volume size are all affected by both irradiation and addition of fillers.

It is shown that the replacement of a part of sulfur atoms with selenium atoms in a TlInS₂ single crystal stimulates the formation of a single-phase state with a monoclinic structure (space group $C_2$/$c)$ in TlInS${}_x$Se${}_{2-x}$ ($x=1$). Irradiation with 2 MeV electrons and a fluence of $2\times 10^{17}$ electron/cm² of powder TlInS${}_x$Se${}_{2-x}$ ($x=1$) leads to an increase in the crystallite size from 56.5 nm to 65 nm, which is most likely associated with a decrease in the interface.

The difference between the surface morphology of the synthesized TlInS${}_x$Se${}_{2-x}$ ($x=1$) single crystal and the surface morphology of the TlInS₂ single crystal is established, which consists in a decrease in the height and width of the roughness in TlInS${}_x$Se${}_{2-x}$ ($x=1$). Irradiation of a TlInS${}_x$Se${}_{2-x}$ ($x=1$) single crystal with electrons with a fluence of $2\times 10^{17}$ electron/cm² does not lead to a change in the height of the tubercle on its surface, and the average value of its width increases more than ten-fold.

The identity of the peaks in the Raman spectra of the TlInS${}_x$Se${}_{2-x}$ ($x=1$) single crystal before and after its irradiation with electrons with an energy of 2 MeV and upto a fluence of $2\times 10^{17}$ electron/cm², along with the absence of a shift of the peaks, indicates the radiation resistance of the TlInS${}_x$Se${}_{2-x}$ ($x=1$) single crystal.

Temperature dependences of the electrical resistance along the c-axis of ${\mathrm{\text{YBa}}}_2{\mathrm{\text{Cu}}}_3{\mathrm{\text{O}}}_{7-\delta }$ single crystals are investigated before and after irradiation with electrons at 0.5–2.5 MeV energies. The irradiation was done at $T\lesssim 10$ K and the irradiation dose was varied from $1.4\times 10^{18}{\mathrm{\text{cm}}}^{-2}$ to $8.8\times 10^{18}{\mathrm{\text{cm}}}^{-2}$. An enhancement of the charge carriers localization with increase of the irradiation dose has been revealed. A crossover from the pseudogap (PG) regime to the variable-range hopping conductivity has been observed.

The effect of room-temperature annealing on the basal-plane conductivity of YBCO single crystals is investigated after their irradiation with fast electrons. It is revealed that the excess conductivity $\mathrm{\Delta }\sigma (T)$ of the samples obeys an exponential temperature dependence in a broad temperature range $T_f<T<T^{\ast }$. Here, $T_f$ is the crossover temperature from the pseudogap to the fluctuation conductivity regime. The description of the excess conductivity with the expression $\mathrm{\Delta }\sigma \propto T/T^{\ast }exp({\mathrm{\Delta }}^{\ast }/T)$ can be interpreted in terms of the mean-field theory where $T^{\ast }$ corresponds to the mean-field transition temperature to the pseudogap state and the dependence $\mathrm{\Delta }\sigma (T)$ is described within the framework of the BCS-BEC crossover theory.

High detection efficiency and good room temperature performance of Schottky barrier CdTe semiconductor detectors make them well suited especially for X-ray and gamma-ray detectors. In this contribution, we studied the effect of electron irradiation on the spectrometric performance of the Schottky barrier CdTe detectors manufactured from the chips of size $4\times 4\times 1$ mm³ with In/Ti anode and Pt cathode electrodes (Acrorad Co., Ltd.). Electron irradiation of the detectors was performed by 5 MeV electrons at RT using a linear accelerator UELR 5-1S. Different accumulated doses from 0.5 kGy up to 1.25 kGy were applied and the consequent degradation of the spectrometric properties was evaluated by measuring the pulse-height gamma-spectra of ${}^{241}\mathrm{Am}$ radioisotope source. The spectra were collected at different reverse voltages from 300 V up to 500 V. The changes of selected significant parameters, like energy resolution, peak position, detection efficiency and leakage current were monitored and evaluated to quantify the radiation hardness of the studied detectors. The results showed remarkable worsening of their spectrometric parameters even at relatively low applied doses of 1.25 kGy.