Bit flip errors were detected in microcontroller memory cells after irradiation by laser accelerated proton beams. The protons with energies of up to 6 MeV originated from the back surface of 6-μm-thick aluminum foils under the action of laser pulses from 200 TW femtosecond facility. It was established that the failures were caused by single event effects and cross section of the effects was estimated. The experiment demonstrates for the first time the possibility of using laser-plasma accelerators to study single event effects from low-energy protons.

To increase the efficiency of laser-driven ion acceleration, a method for in-situ target cleaning by heating action of the continuous wave (CW) laser was developed. On a 20 TW picosecond laser facility, experiments on ion acceleration from heated Ti and Ta targets of 1 μm thickness were conducted. CW laser cleaning allowed an increase in carbon and oxygen ion energies by 2.5 times up to 65 MeV. Ta ions with energies of up to 47 MeV were registered in experiments. Their linear energy transfer exceeds 35 MeV·cm2/mg, thus making these particles suitable for the investigation of single event effects in microelectronic devices induced by protons from solar flares.

We outline the results of experiments in the generation of X-ray laser radiation on the 4d-4p Ni-like ion transitions at a wavelength lambda = 189 angstrom under sequential irradiation of plane targets by two laser pulses focused to a line. These experiments were executed on the Sokol-p picosecond laser facility. The average energy of a 4-ps long ultrashort pump pulse was equal to 6.5 J, the energy of a 0.44-ns long prepulse was equal to 2.7 J, and the time delay between them was equal to 1.5 ns. The effective gain for short target lengths was equal to similar to 24 cm(-1). In the travelling pump wave regime, which was realised using a ladder mirror, we obtained an 8-fold increase in output X-ray laser energy in comparison with the output energy obtained in the ordinary target irradiation regime.

We present the results of experimental investigation of ion and electron fluxes produced by irradiating thin foils with laser USPs. These experiments were carried out on the Sokol-P laser facility (pulse duration ∼1 ps, power ∼20 TW) using lavsan, aluminium, and copper targets of equal thickness (∼5 μm). Ions were recorded employing Thomson spectrometers and a time-of-flight spectrometer with a silicon semiconductor detector. To record electrons, use was made of electron spectrometers involving the rotation of particle trajectories by 180° in magnetic field. The ionic composition of the charged particle beam was determined and the beam shape was investigated in relation to the target material.

The design, assembly, and alignment of a Kirkpatrick-Baez X-ray microscope are described. A technique for the experimental evaluation of the resolving power of the microscope is outlined. This microscope permits obtaining simultaneous images of laser target plasmas in narrow energy regions belonging to the 0.3-1.5-keV X-ray range with a resolution of similar to 2 mu m.

A RKK-1-100 automated X-ray calibration facility has been developed. This system allows studies of surfaces, near-surface layers, interfaces, and multilayer structures within a wide range of wavelengths of 0.1–100 nm. The first results of quantitative certification of the roughnesses of flat quartz substrates and substrates with evaporation-deposited UNi layers have been obtained. X-ray optical constants for thin UNi layers have been measured.

Results from experimental studies of bremsstrahlung and characteristic radiation spectra from laser targets irradiated with ultrashort laser pulses with intensities of up to ∼1019 W/cm2 are presented. The continuous spectra of hard X-ray emission from Ta and Al targets and the line spectrum of copper were measured. The temperature of fast electrons was obtained from the measured hard X-ray spectra, and the Kα radiation yield from Ta was measured. The energy conversion efficiency of laser radiation into the copper characteristic radiation was obtained from the measured yield of Kα radiation.

Results from experimental studies of bremsstrahlung and characteristic radiation spectra from laser targets irradiated with ultrashort laser pulses with intensities of up to ∼10 19 W/cm 2 are presented. The continuous spectra of hard X-ray emission from Ta and Al targets and the line spectrum of copper were measured. The temperature of fast electrons was obtained from the measured hard X-ray spectra, and the K α radiation yield from Ta was measured. The energy conversion efficiency of laser radiation into the copper characteristic radiation was obtained from the measured yield of K α radiation.

Исследование рентгеновских спектров на установке СOКОЛ-П при интенсивности лазерного… 63 УДК 533.9.082 ИССЛЕДОВАНИЕ РЕНТГЕНОВСКИХ СПЕКТРОВ НА УСТАНОВКЕ СOКОЛ-П ПРИ ИНТЕНСИВНОСТИ ЛАЗЕРНОГО ИЗЛУЧЕНИЯ 10 17 -10 19 Вт/см 2 В.И.Афонин, Д.А.Вихляев, Д.С.Гаврилов, А.Г.Какшин, Е.А.Лобода, В.Ю.Политов, А.В.Потапов, К.В.Сафронов, П.А.Толстоухов (Российский федеральный ядерный центр -Всероссийский НИИ технической физики им.академика Е.И

Спектрометр мягкого рентгеновского излучения на основе сферических зеркал… 69 УДК 533.9.082 СПЕКТРОМЕТР МЯГКОГО РЕНТГЕНОВСКОГО ИЗЛУЧЕНИЯ НА ОСНОВЕ СФЕРИЧЕСКИХ ЗЕРКАЛ ПОЛНОГО ВНЕШНЕГО ОТРАЖЕНИЯ ДЛЯ ИССЛЕДОВАНИЯ ПЛАЗМЫ НА ЛАЗЕРНОЙ УСТАНОВКЕ СОКОЛ-П Д.А.Вихляев, Д.С

Results of experiments on proton acceleration from aluminum foils and organic films irradiated by laser pulses with intensities of up to 2 × 10 19 W/cm 2 are presented. To prevent thin targets from destruction by the superluminescence prepulse, a fast light shutter based on a Pockels cell was introduced in the amplifying system of the SOKOL-P facility. As a result, the energy contrast with respect to the superluminescence prepulse increased to 4 × 10 6 , which made it possible to carry out experiments on the irradiation of targets with thicknesses less than 100 nm. It is found that the target material insignificantly affects the yield of accelerated protons.

A time-of-flight spectrometer based on a fast plastic scintillator was developed to study the spectral and angular distribution of charged particles emitted from laser-produced plasmas. The measured time resolution of the spectrometer was ∼0.3 ns, which made it possible to observe the fine structure in the spectrum of protons originated from the back surface of the target in experiments on the SOKOL-P laser facility.

A technology of depleted uranium thin films, which can be used as high-reflectivity X-ray mirrors at a wavelength of 4.5 nm, is presented. The coefficient of X-ray reflection by these mirrors varies from 90 to 10% at grazing angles between 1° and 10°. The stability of the reflection coefficients for 200-Å-thick depleted uranium films covered by a protective carbon layer 100 and 200 Å in thickness and for 200-Å-thick uranium-nickel films with a nickel content of 9 and 23 wt % is studied. A high-reflectivity mirror is fabricated with the goal of increasing the X-ray radiation intensity in RKK-1-100 X-ray calibration equipment. Advice on fabrication of X-ray mirrors based on depleted uranium films is given.

Investigations of an electric discharge in a capillary filled with preliminarily ionized xenon are currently performed on the SIGNAL accelerator. The discharge current is 20–50 kA, and the current rise time is 20–50 ns. The design of the accelerator is described and the results of studies of the capillary-emitted radiation performed with a vacuum X-ray diode and frame X-ray streak camera are presented. The total yield of X rays in the energy range 50–120 eV is ∼(30–40) mJ/sr, and the maximum radiation power is 0.4–0.5 MW/sr.

The transient collisional excitation (TCE) scheme was used to obtain generation of X-ray laser radiation on the 3p-3s transitions of the Ne-like Ti-ions at 10 TW SOKOL-P laser developed at RFNC-VNIITF. The Nd-laser light was focused in a line with length from 2 up to 8 mm and width of 30 microns. Two successive pulses irradiated the polished Ti-slab. The duration of prepulse was equal to 400 ps and a pumping pulse had duration of 4 ps; the delay between pulses equals to 1.5 ns. The Nd-laser energy was about of 10 J and the ratio of energy in prepulse and basic pulses was equal to 1:2. The grating spectrometer equipped with a focusing mirror and CCD detector was used for measurement of the X-ray laser line at 32.6 nm. A small signal gain about of 30 cm-1 was obtained in experiments with target length from 2 up to 4 mm. The 32.6 nm line radiation with energy about of 1 ¼J and divergence of 9 mrad were registered in SOKOL-P experiments with target length of 8 mm.

Experimental results are presented for proton acceleration from the back of a target irradiated by laser pulses with intensities up to 2 × 10 19 W/cm 2 generated by the SOKOL-P facility. The proton acceleration efficiency increases with decreasing of the target thickness. However, thin targets are destroyed by the amplified spontaneous emission (ASE) prepulse before the main pulse arrival. An additional optical switch based on a Pockels cell has been used in the amplification section to carry out the experiments with ultrathin foils. As a result, the energy contrast with respect to the ASE prepulse has been increased up to 4 × 10 6 . Owing to high contrast, the experiments on studying proton acceleration from foils with thicknesses less than 100 nm have been carried out.

In this paper, we present experimentally determined reflection factors of mirrors based on the depleted uranium and dependence of reflection factor on time of presence of samples on air.

X-ray spectra from targets irradiated by picosecond laser pulses with intensities of 3 × 10 17 -10 18 W/cm 2 have been studied experimentally on the SOKOL-P facility. Both massive metal targets and multilayer targets with a buried emitting layer have been examined. The measurement results are interpreted by using numerical simulations and theoretical analysis. Experimental data on the X-ray continuum in the photon energy range of 0.8–6 keV and the line spectra of hydrogen-and helium-like aluminum ions are found to agree satis-factorily with numerical results.