A search for the muon-catalyzed fusion reaction d + d -> He-4 + gamma in the dd mu muonic molecule was performed using the experimental installation TRITON with BGO detectors for gamma-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect gamma-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the dd mu state J = 1 was obtained at the level of eta(gamma) <= 8 x 10(-7) per fusion.

A search for the muon-catalyzed fusion reaction d + d → 4He + γ in the ddμ muonic molecule was performed using the experimental installation TRITON with BGO detectors for γ-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect γ-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the ddμ state J = 1 was obtained at the level of η γ ≤ 8 × 10−7 per fusion.

The muon-catalyzed fusion ( µ CF) process in tritium was studied by the µ CF collaboration on the muon beam of the JINR Phasotron. The measurements were carried out with a liquid tritium target at the tem- perature 22 K and density approximately 1.25 of the liquid hydrogen density (LHD). Parameters of the µ CF cycle were determined: the tt µ muonic molecule formation rate λ tt µ = 2.84(0.32) µ s -1 , the tt µ fusion reaction rate λf = 15.6(2.0) µs -1 , and the probability of muon sticking to helium ωtt= 13.9(1.5)%. The results agree with those obtained earlier by other groups, but better accuracy was achieved due to our unique experimental method.

We investigated scintillation and luminescence properties of GdI3:1% Ce3+. It shows a light yield of 47 000 photons/MeV recorded with a Hamamatsu R1791 photomultiplier tube (PMT). Using an Advanced Photonix 630-70-73-510 avalanche photodiode (APD), the light output of this sample is 44 000 electron-hole pairs/MeV. The best energy resolution at 662 keV of 4.7% was recorded at 10 degrees C with the APD with a shaping time of 0.5 mu s. At room temperature (RT), the gamma-scintillation decay curve of GdI3:1% Ce3+ shows a fast component of 45 ns, which is the same as the intrinsic Ce3+ decay time, and that contributes 70% to the total light yield. GdI3:1% Ce3+ shows no afterglow at RT. Temperature dependence ranging from 80 to 600 K of X-ray excited emission spectra, pulse height spectra, scintillation decay curves and optically excited decay curves of Ce3+ emission are also presented.

The paper presents two cerium doped lutetium silicate crystals: pyrosilicate Ce:Lu2Si2O7 (LPS) and Ce: Lu2(1-x)Y2xSiO5 (LYSO). These two crystals exhibit the expected requirements for gamma detection: high density and high atomic number, high scintillation light yield, good energy resolution and fast response. LPS and LYSO crystals doped with cerium were grown by the Czochralski process. The crystal growth parameters were studied and optimized. Development of scintillators requires good understanding of the scintillation process. The location within the forbidden band gap of the localized lanthanide energy levels is analyzed by time resolved spectroscopy and thermoluminescence studies.

The cause of the relatively low scintillation light yield of PrBr3:Ce3+ is investigated by means of optical spectroscopy, the temperature dependence of scintillation properties and the temperature dependence of optically excited decay curves of undoped and Ce3+-doped PrCl3 and PrBr3. The integrated intensity of x-ray excited luminescence of PrBr3:5% Ce3+ shows that the light yield at room temperature (RT) is two times less than at 80 K. The decay time of Ce3+ emission optically excited to its 5d band in PrBr3:5% Ce3+ has a single exponential decay of 11.0 ± 1.1 and 6.0 ± 0.6 ns at 10 K and RT, respectively. It is proposed that Ce3+ emission is quenched by a metal-to-metal charge transfer of followed by emission of Pr3+ which is strongly concentration quenched.

The scintillation properties of Ce 3+ doped ternary cesium rare‐earth halides are reported. We investigated Cs 3 Lu 2 I 9 :Ce 3+ , Cs 3 Gd 2 I 9 :Ce 3+ , Cs 3 LaBr 6 :Ce 3+ and Cs 3 LuI 6 :Ce 3+ . Cs 3 Lu 2 I 9 :Ce 3+ and Cs 3 LaBr 6 :Ce 3+ exhibit the highest light yields under γ‐ray excitation of 22800 ± 2300 and 10400 ± 1000 photons per MeV of absorbed γ‐ray energy, respectively. Optical spectroscopy and scintillation decay time curves of these compounds are presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The neutron back scattering technique is used to search for land mines. Advantages of this technique are: the speed of detection, the ability to detect metal free mines, and the insensitivity to metal and pebbles.The method is sensitive to soil moisture, therefore a desert environment is perfectly suited for application of the neutron backscattering technique. Tests were performed using various dummy mines and real defused mines in the Egyptian desert.

The luminescence and scintillation properties of Cs2LiLuCl6:0.5%Ce3+ are presented. Special attention is devoted to a 9.4ns fast emission at 275nm that can only be excited via the highest cubic field 5de state of Ce. Contrary to Cs3LuCl6 and Cs2LiYCl6, where the same type of fast emission was observed, the emission in Cs2LiLuCl6 is still observed at room temperature. Assuming that the 5de state is located inside the host conduction band (CB), we propose that the emission originates from a mixed state at or just below the bottom of the CB and ends at the 4f ground state of Ce3+. To proof this model we studied the thermal quenching of the anomalous luminescence and performed X-ray photoelectron spectroscopy. A model for a temperature-activated energy transfer from the anomalous state to the lowest 5dt excited state of Ce3+ explains most of the results. Besides the 275nm emission, the material shows 5dt–4f Ce3+ emission at 370 and 406nm and 2ns fast core-valence luminescence when excited with 16–22eV photons. The scintillation properties of Cs2LiLuCl6:Ce are briefly discussed.

The neutron back scattering technique may be used to search for low-metallic land mines. An advantage of this technique is the speed of detection: the scanning speed may be made comparable to that of a metal detector. The method is sensitive to soil moisture. A limitation of the method is therefore that the soil must be sufficiently dry. The neutrons are produced with a pulsed neutron generator. An image of the back scattered thermal neutron radiation is obtained with a two dimensional position sensitive detector. Getting optimal settings for the detector system is described. The mine detection time as function of the neutron pulse parameters is investigated. Results with various dummy mines are presented.

We are currently investigating the possibility of using continuous scintillator blocks as detectors for small animal PET. These block detectors consist of a few cm(3) of scintillating material, read out by one or two APD arrays. The entry point of an incoming gamma photon is reconstructed from the distribution of the scintillation light over the APD pixels. To optimize the detector design, the influence of different parameters is investigated using simulations. As a measure of detector performance that is independent of the reconstruction algorithm used, the Cramer-Rao lower bound on the reconstruction of the coordinates of a point source of light inside the crystal is calculated. Results are presented for different detector designs, surface finishes and pixel sizes. A comparison with resolutions obtained from simulations involving beams of 511 keV annihilation photons indicates that this approach gives valid results.