[en] The way of understanding laser matter experiments is to use specific instrumentation which needs new techniques, in terms of triggering, fast high voltage ramps generation and fiducial, using fast optoelectronic switches. Some experiments realized around large lasers as Phebus and P102 installed on the CEA-Limeil-Valenton center and described in this paper illustrate the possible applications of these cells for the always more exacting requirements of the physics of the condensed plasmas. (author)

[en] The efficient THz generation by optical rectification from an indigenously grown organic DAST crystal using the 140 fs oscillator laser pulses tunable in between 780 and 850 nm, has been reported in this article. The generated THz pulse profile and powers have been measured using the photoconductive (PC) antennas and pyroelectric detector, respectively. The highest THz peak amplitude and power is obtained at 825 nm central wavelength. The theoretically explanation of the enhancement of THz radiation based on the matching of average optical group refractive index and average THz refractive index of the DAST crystal at 825 nm. In addition, the dependence of THz peak amplitude and THz power on laser power have been carried out. The measured quantum conversion efficiency (QCE) of 0.5 and 1.5 THz bands are of the order 3.7 × 10⁻³, 1.4 × 10⁻³, respectively. Finally, an attempt has been made to study the effect of polarizations on generated THz signal. (author)

[en] Electron beam temperature, βperpendicular (= vperpendicular/v), is important to control for the development of high dose flash radiographic bremsstrahlung sources. At high voltage (> 5 MV) increasing electron beam temperature has a serious deleterious effect on dose production. The average and time resolved behavior of beam temperature was measured during radiographic experiments on the HERMES III accelerator (10 MV, 50 kA, 70 ns). A linear array of thermoluminescent dosimeters (TLDs) were used to estimate the time integrated average of beam temperature. On and off-axis photoconducting diamond (PCD) detectors were used to measure the time resolved bremsstrahlung dose rate, which is dependent on beam energy and temperature. The beam temperature can be determined by correlating PCD response with accelerator voltage and current and also by analyzing the ratio of PCD amplitudes on and off axis. This ratio is insensitive to voltage and current and thus, is more reliable than utilizing absolute dose rate. The data is unfolded using comparisons with Monte Carlo simulations to obtain absolute beam temperatures. The data taken on HERMES III show abrupt increases in βperpendicular midway through the pulse indicating rapid onset of beam instability

[en] The principles of operation and simplified model and the unique interesting characteristic of diamond photoconducting detectors (PCDs) were presented. The detectors were used to measure soft X rays in the experiment of laser-Au planar target interaction. The X ray conversion was given about 27% based on the result of the reference

[en] A new high-resolution detector has been developed for use in a slot-scanned digital mammography system. The detector is a hybrid device that consists of a CCD operating in time-delay integration mode that is bonded to a 150-μm-thick CdZnTe photoconductor array. The CCD was designed with a detector element pitch of 50 μm. Two devices were evaluated with differing crystalline quality. Incomplete charge collection was a source of reduction in DQE. This occurs in both devices due to characteristically low mobility-lifetime products for CdZnTe, with the greatest losses demonstrated by the multicrystalline sample. The mobility-lifetime products for the multicrystalline device were found to be 2.4x10^-4 and 4.0x10^-7 cm²/V for electrons and holes, respectively. The device constructed with higher quality single crystal CdZnTe demonstrated mobility-lifetime products of 1.0x10^-4 and 4.4x10^-6 cm²/V for electrons and holes. The MTF and DQE for the device were measured at several exposures and results were compared to predictions from a linear systems model of signal and noise propagation. The MTF at a spatial frequency of 10 mm^-1 exceeded 0.18 and 0.56 along the scan and slot directions, respectively. Scanning motion and CCD design limited the resolution along the scan direction. For an x-ray beam from a tungsten target tube with 40 μm molybdenum filtration operated at 26 kV, the single crystal device demonstrated a DQE(0) of 0.70±0.02 at 7.1x10^-6 C/kg (27 mR) exposure to the detector, despite its relatively poor charge collection efficiency

[en] The InAsSbP composition type-II quantum dots (QDs) are grown on a InAs(1 0 0) substrate from In-As-Sb-P quaternary liquid phase at a constant temperature in Stranski–Krastanow growth mode. Device structures in the form of photoconductive cells are prepared for investigation. Magnetospectroscopy and high-precision capacitance spectrometry are used to explore the QDs structure’s electric sheet resistance in a magnetic field and the capacitance (charge) law at lateral current flow. Aharonov–Bohm (AB) oscillations with the period of δB = 0.38   ±   0.04 T are found on the magnetoresistance curve at both room and liquid nitrogen temperatures. The influence of the QDs size distribution on the period of AB oscillations is investigated. The magnetoresistance hysteresis equals to ∼50 mΩ and ∼400 mΩ is revealed at room and liquid nitrogen temperature, respectively. The capacitance hysteresis (CH) and contra-directional oscillations are also detected. Behavior of the CH versus applied voltage frequency in the range f = 10"3–10"6 Hz is investigated. It is shown that the CH decreases with increasing frequency up to 10"6 Hz. The time constant and corresponding frequency for the QDs R–C parallel circuit (generator) equal to τ = 2.9   ×   10"−"7 s and f _0 = 5.5   ×   10"5 Hz, respectively, are calculated. (paper)

[en] Different methods of trap parameter measurement are analysed. Transient photoconductivity and thermally stimulated effects were used to investigate the influence of traps in LEC SI-GaAs and high-resistivity epitaxial GaAs. The peculiarities of the TSC were analysed and shown to be related to the influence of crystal micro-inhomogeneities. (author)

No abstract available

No abstract available

[en] A trans microscope registration electronic system using cadmium sulphide photoconductive cell as light dependent resistor is described. This photocell has a spectral response similar to that of the human eye and enable registration of cellular motion phenomena along with their microscopic observation. The photocell is of the type ORP 12 which when replacing one of the oculars of the light microscope, can register changes in light intensity caused due to any movement of the studied living objects. The large diameter sensing element allows registration of full size of the contractile objects with a wide range of spectral sensitivity. Its application is reported for investigating the oscillatory contraction activity of plasmodial strands of the slime mold physarum polycephalum. (authors). 15 refs., 7 figs.,