Introduction. Diamond is one of the most suitable materials for particle detectors, due to a wide band gap and a high radiation resistance of this material. However, diamond sensitive elements for detectors remain rare and expensive, which hinders their widespread use in nuclear physics and medicine. Problem Statement. In recent years, new technologies for growing HPHT diamonds in cubic presses have been developed. They have allowed obtaining up to 50 high-perfection single crystal diamonds weighing up to 10 carats in one cycle. However, the physical properties of HPHT diamonds grown in modern presses have not been sufficiently studied, and the results of the application of such diamonds in ionizing radiation detectors have been unknown so far. Purpose. The development of a particle detector with sensitive elements based on HPHT diamonds grown in a cubic high-pressure apparatus and the study of its characteristics. Materials and Methods. Growing diamonds by the temperature gradient method in a cubic high-pressure apparatus. Particle detector. Irradiation with alpha particles. Results. The temperature gradient method has been used to grow 7-9 mm diamond single crystals in a cubic high-pressure apparatus, and 0.4 mm thick diamond plates have been made of cubic and octahedral growth sectors. The physical properties of the samples have been studied. The detectoramplifier has been developed, and the detector has been tested when irradiated with alpha particles. The results have showed reliable detection of ionizing events caused by alpha particles and the registration of induced pulses with an amplitude of 70 200 mV. Conclusions. The particle detector with diamond plates made of cubic growth sectors of IIPHT diamonds gown in a high-pressure cubic apparatus from the Fe -Ni-C growth system when irradiated with alpha particles has showed the ratio of full width at half maximum of pulse (FWIIM) of about 1 ns, which corresponds to the world's best analogs of diamond detectors.

Nanomechanical and I-V characterization of a conductive coating on an HPHT diamond substrate

The HPHT diamond Schottky diode was assembled as a Metal/Intrinsic/p-doped structure betavoltaic cell (BC) with a very thin (1 pm) drift layer and tested under 5-30 keV electron beam irradiation using a scanning electron microscope (SEM). The effect of the beta-radiation energy and the backscattering of electrons on the energy conversion was studied. From the results obtained, it is shown that, the efficiency of the investigated BC increases from 1.01 to 3.75% with the decrease of beta-particle energy from 30 to 5 keV due to an increase of the electron beam absorption in a thin drift layer. Maximum efficiency is achieved when the electron beam energy is close to the average beta-decay energy of H-3. The BC maximum output power of the 1.6 mu c. was obtained at an electron beam energy of 15 keV, that matches the beta-decay energy of Ni-63. The total BC conversion efficiency at 15 keV electron-beam energy is about 3%. The calculations indicated that a preferable beta-source for the diamond based BCs with a thin (1 mu m) drift layer is Ni-63.

The spatial resolution of a scanning tunneling microscope (STM) can be enhanced using light element-terminated probes with spatially localized electron orbitals at the apex atom. Conductive diamond probes can provide carbon atomic orbitals suitable for STM imaging with sub-Ångström lateral resolution and high apex stability crucial for the small tunneling gaps necessary for high-resolution experiments. Here we demonstrate that high spatial resolution can be achieved in STM experiments with single-crystal diamond tips, which are generally only considered for use as probes for atomic force microscopy. The results of STM experiments with a heavily boron-doped, diamond probe on a graphite surface; density functional theory calculations of the tip and surface electronic structure; and first-principles tunneling current calculations demonstrate that the highest spatial resolution can be achieved with diamond tips at tip-sample distances of 3-5 Å when frontier p-orbitals of the tip provide their maximum contribution to the tunneling current. At the same time, atomic resolution is feasible even at extremely small gaps with very high noise in the tunneling current.