Luminescence decay in AgCl crystals

The kinetics of luminescence decay of single crystal plates of AgCl was measured at the temperature of liquid nitrogen. Luminescence decay first takes place (fort≦2·5× ×10^?3 sec) according to a hyperbole and then according to an exponential. The constantsa anda of the hyperbolic andt of the exponential dependence were measured for different intensity of the exciting radiation in normal and deformed samples and in samples irradiated withb-particles during measurement.     

Luminescence centres in pure AgCl crystals

The temperature dependence and the influence of pressure on band width of blue-green luminescence were measured in pure AgCl crystals. The comparison of results obtained with other published data support the existence of two luminescence centres (in the temperature ranges between 130–160°K and between 20–30°K).     

Luminescence of AgCl crystals at room temperature after ruby laser excitation

Emission spectrum of pure AgCl crystals at room temperature after ruby laser excitation was measured. The emission consists of a continuous fluorescence band with the maximum at about 460 nm which is at sufficiently high excitation intensities covered with characteristic line structure emission. The appearance of continous emission at this temperature was in accordance with experimental results explained by the increase of the radiative transition probability in AgCl crystals.     

Etch pits in AgCl crystals

Single crystal sheets have been prepared by the capillarity method. The dislocations can be revealed with a sodium thiosulphate solution at surface orientations from two regions in the basic triangle. These are: region A around 001 pole up to ≈25°, and region B around 111 pole up to ≈pa 10°. In the remaining region C of the basic triangle the dislocations do not etch. In region A the etch pits have the shape of pyramids. In region B they are triangular pyramidal in shape. Evidence is given that the edge and screw components of annealed and fresh dislocations are revealed by etching. At surface orientations near either the {00l} or {111} planes the slip can be activated in such zones 〈110〉 that are nearly parallel to the surface of the sheets. The slip bands are then straight and predominantly of the edge type.     

Multiplication of electronic excitations in AgCl crystals

The kinetics of pulse conduction in silver chloride single crystals is investigated in the temperature range 12–300 K upon picosecond excitation with x-ray bremsstrahlung. It is found that the experimentally observed concentration of conduction electrons is nearly twice as high as the concentration of electron-hole pairs generated by an exciting pulse. This effect is associated with the chain multiplication of band charge carriers.     

Pulse measurements of thermostimulated currents in AgCl crystals

The course of thermostimulated currents in AgCl crystals was measured in a temperature region between 200 and 300K. Maxima at 240, 275 and 290K were observed on the curves obtained.     

Luminescence of YTaO4 single crystals

In this paper the absorption spectra, photo- and X-ray luminescence, and scintillation characteristics of monocrystalline YTaO₄ have been studied. The intensive band with maximum at 350 nm in X-ray luminescence spectra at room temperature has been observed. The scintillation effiency of YTaO₄ monocrystal is about 20%.     

On slip in AgCl crystals at room temperature

At moderately wavy and branched slip bands on the surfaces of sheets of AgCl crystals the distribution of slip lines has been observed by means of the electron microscope. From the results it can be deduced that the cross slip of screw dislocations takes place. The divergence of the ends of slip bands has also been observed, which can be as well explained by the cross slip. From the active slip direction and the directions of straight slip lines in the cross-slip regions the microscopic slip planes have been determined. They lie in the region roughly limited by the {113} and {331} planes and the problem is discussed whether these planes are low-index crystallographic planes.     

Luminescence of AgCl excited by u.v. laser light

The spectral distribution and decay of the blue-green luminescence of AgCl has been measured at very low temperatures, using u.v. laser excitation. A structure was observed in the emission band at 77°K. The decay consists of three processes: a) a very fast process which follows the laser pulse (10^–8 sec), b) a fast exponential process which is also observed with low intensity u.v. excitation,(10^–4–10^–5 sec) and, finally, c) a slow exponential process (seconds).