A procedure is described for determining the basic parameters of linear-sweep electron-optical cameras. The techniques are considered for measuring the limiting temporal resolution and dynamic range of the PS-1/S1 camera using a femtosecond laser and sinusoidal-modulated laser radiation.

Temporal parameters of synchrotron pulse radiation at damping ring (DP) installation of VEPP-5 type were measured with the help of PS-1/S1 picosecond streak camera having 1.5 ps time resolution. These measurements were proceeded within 400-900 nm spectral range. It has been shown that our streak camera may record either a train of electron bunches with ns-duration or internal structure inside a single bunch. We were able to record the distance ~ 1.5 ns between separate bunches as well as their amplitude, which depends on particle numbers inside a bunch. Depending on linear accelerator mode of operation it was possible to define a single bunch duration, which was deviated within the range of 20-100 ps. The temporal structure of a single bunch was measured with 1.5 ps time accuracy. As a result, the VEPP-5 damping ring parameters were optimized, and particles injection conditions were improved. In addition, we have measured the temporal parameters of Vavilov-Cherenkov radiation (VCR) emitted by electron beam of linear accelerator. Our results provided important information on electron bunches formation and their quality inside linear accelerator before electrons injection inside a damping ring. Another series of experiments were done at VEPP-4M electron-positron collider. The dependence of beam length of the beam current measured with streak-camera allowed us to compute the wide-band impedance of the accelerator. The same data were obtained at Siberia-2 synchrotron radiation source (NRC “Kurchatov Institute”, Moscow).

Using a picosecond image converter camera with a linear sweep (PS-1/S1 streak camera developed at GPI RAS, Moscow), we have measured temporal parameters of Vavilov – Cherenkov radiation pulses. The radiation was generated by relativistic electrons passing through a quartz cone mounted on the axis of a vacuum chamber of a linear accelerator, which is a part of the VEPP-5 injection complex at the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences (BINP SB RAS, Novosibirsk). The data obtained in these experiments provide an insight into the processes of formation of electron bunches and their ‘quality’ in a linear accelerator prior to injection of electrons into the accumulator-cooler. A conclusion is made regarding the advisability of streak camera application in tuning the linear accelerators for optimisation of electron bunch parameters.

The application of a PS-1/S1 picosecond streak camera (SC), which was developed at the General Physics Institute (Russian Academy of Sciences) for investigating fast processes in semiconductor physics, laser physics, and accelerator engineering, is described. It is shown that using the PS-1/S1 SC it is possible to record one-dimensional images (restricted by a narrow slit) of fast processes with a time resolution of no worse than 1 ps in a wide spectral range: from UV (115 nm) to near-IR (1.5 μm) radiation with a dynamic recording range of ≥10. The presented experimental results show the wide potential capabilities of applying the developed SC in various fields of experimental physics.

A PS-1/S1 picosecond streak camera with a linear sweep is used to measure temporal characteristics of synchrotron radiation pulses on a damping ring (DR) at the Budker Institute of Nuclear Physics (BINP) of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk). The data obtained allow a conclusion as to the formation processes of electron bunches and their 'quality' in the DR after injection from the linear accelerator. The expediency of employing the streak camera as a part of an optical diagnostic accelerator complex for adjusting the injection from a linear accelerator is shown. Discussed is the issue of designing a new-generation dissector with a time resolution up to a few picoseconds, which would allow implementation of a continuous bunch monitoring in the DR during mutual work with the electron-positron colliders at the BINP.

The well-established PIF-01/S1/P43 picosecond streak tube, designed 30 years ago and still manufactured at the A.M. Prokhorov General Physics Institute, was modified by replacing its traditional P43 phosphor screen with a P47 one having approximately three orders of magnitude shorter decay time. The experimental measurements of this decay time were provided by PIF-01/S1/P47 image tube photocathode irradiation either with a single or a train of 8 ps laser pulses separated by 8 ns from each other at a 1.08 mu m wavelength. The results of our preliminary measurements of P47-BH phosphor (manufactured by Phosphor Technology Ltd) indicate the possibility of employing the PIF-01/S1/P47 streak tube for synchrotron diagnostics at a units megahertz repetition rate without the negative influence of 'ghost images' from the previous streak records.

A PS-1/S1 picosecond image-tube streak camera (ITSC) with slit scan (streak camera), developed and manufactured at the General Physics Institute RAS, has been used to measure the spatiotemporal characteristics of ultrashort laser pulses generated by a petawatt-power laser installation ‘FEMTO’ at the Institute of Laser Physics Research in Sarov. It is found that such a camera is suitable for measuring the spatial and temporal parameters of single laser pulses with an accuracy of about one picosecond. It is shown that the intensity time profile of a train of picosecond pulses may be precisely defined for the pulses separated in time by a few picoseconds. The camera allows the contrast of radiation to be determined with a high (no less than ) accuracy; spatial distribution of the laser pulses can be measured with an accuracy of tens of microns, and the temporal separation of single laser pulses can be identified with an accuracy of .

To improve operation parameters (S/N ratio, dynamics range, time resolution, etc.) of picosecond streak tubes, the traditional P20/P43 phosphor screens can be replaced by the others (P46/P47) having much faster decay time of the luminescence output. We provide comparative dynamic measurements of the home-made phosphor screens inside the picosecond PIF-01 streak tubes under illumination of their photocathodes by a single picosecond laser pulse or a train of picosecond laser pulses. We show that the shortest measured decay time for made-in-Russia phosphor screens (Y3Al5O12:Ce) is close to several hundreds of nanoseconds not only at a half-intensity level but also at a level of 10−3 and even smaller. Furthermore, the photoelectron-to-photon conversion factor is not drastically smaller than in the traditional phosphor materials. This means that application of streak tubes supplied with fast-response phosphor screens may substantially improve the tube capabilities in the accumulation mode, and this is very important for time-resolved diagnostics of electron bunches in accelerators, where continuous accumulation of repetitive signals is needed.

The principles of simultaneous spatial and temporal focusing of photoelectron beams in nonstationary electric fields are theoretically studied and experimentally realised as applied to time-analysing image-converter tubes (ICTs). It is theoretically shown that the use of nonstationary focusing electric fields makes it possible to surpass the theoretical time resolution limit of ICTs (10(-4) s) determined for stationary fields by Zavoisky and Fanchenko in the 40s-50s of the last century. The possibility of forming electron packets with an energy of 10-30 KeV and a subfemtosecond duration (below 10(-15) s) gives impetus to the development of time-resolved electron diffraction, which is a direct method of investigation of atomic-molecular dynamics in solid and gaseous media.

Исследованы погрешности измерений двумя электронно-оптическими системами временного хода интенсивности света в пикосекундном лазерном импульсе. Первая система – это пикосекундная стрик-камера российского производства, вторая система, созданная в Германии, состоит из пикосекундной стрик-камеры, соединенной с двойным спектрографом. Подобные системы тестируются изготовителями с помощью фемтосекундных импульсов, что, однако, не позволяет предсказать погрешности измерений пикосекундных импульсов. Предложены и измерены параметры, характеризующие именно такие погрешности. Установлен характер их изменения при увеличении амплитуды (энергии) измеряемых импульсов, изучено влияние формы сечения светового луча на точность измерений.

Errors of measuring time dependences of the light intensities of picosecond laser pulses by two electron-optical systems are studied. The first system is the picosecond streak camera made in Russia, and the second system, designed in Germany, consists of a picosecond streak camera coupled with a double spec-trograph. The manufacturers test similar systems by using femtosecond pulses, however, this does not allow one to predict errors of measuring picosecond pulses. Parameters that characterize just these errors are proposed and measured. Their behavior is determined, when the amplitude (energy) of the measured pulses increases, and the influence of the cross-section shape of the light beam on the measurement accuracy is studied.

10ps, X-ray streak camera developed at GPI, Photoelectronics Department is intended for photographic recording of high-speed events in visible and soft X-ray spectral regions. The camera contains a picosecond streak tube of PV-003-X type with a photocathode being simultaneously sensitive in visible (250-700 nm) and soft X-ray regions (1-10KeV). Due to this unique feature the camera may be adjusted in the visible light range and afterward, without any further readjustment, be used for high-speed recording in X-ray spectral range. Both single-streak and single-frame modes are available. The streak duration range over the output phosphor screen of 25mm length is 2.5-250ns. Single frame exposure time is between 100 and 500 ns. Dynamic spatial resolution in X-ray spectral range is 7 line pairs/mm. Maximum dynamic recording range is close to 100. The camera triggering delay at maximum streak-speed is less than 50ns with the triggering jitter within +/- 50ps.

Developed is the granulated, Au film-based, semitransparent photocathode consisting of spherical Au nanoparticles. The granulated Au films are activated by a thin layer of cesium and oxygen of about two monolayer thicknesses to decrease the work function down to about 1 eV and gain the photoemission effect in the visible spectrum range. The sensitivity maximum equal to about one mA/W is located in the green spectrum range. The nanoparticles formation and photocathode surface structure are studied with the use of the X-ray photoelectron spectroscopy technique. Those studies have shown that the photoemission effect in the wavelength range lambda > 450 nm is conditioned by excitation of the surface plasmons in quasi-spherical Au nanoparticles. This has allowed manufacturing of a streak tube with the introducible, Au nanoparticles-based photocathode, stability of which has been remaining invariant.

The paper elucidates some new computer modeling and experimental results on the design of a photoelectron gun with time-dependent electric field. The main essence of the new approach is based on the fact that the properly chosen electric field ramp ensures first-order temporal focusing of photoelectron bunch, which is principally impossible in static field previously used. This new technology allows a real breakthrough in time resolution of photoelectron guns and diffractometers intended for time-resolved electron diffraction experiments (TRED).

We report our experimental investigations of the formation and development dynamics of laser plasma produced in gas microvolumes (microplasma) upon multiple ionisation by tightly focused (to a spot 2—3 μm in diameter) high-intensity (up to ≈1017 W cm-2) femtosecond pulses of a Ti:sapphire laser (τp ⋍ 130 fs, λ = 800 nm). Precision interferometric measurements (with a spatial resolution of ≈1.5 μm) were made of the spatiotemporal distribution of the refractive index and electron density in the microplasmas of the air and helium immediately during the action of the exciting femtosecond laser pulse and at the initial stage of free plasma expansion. The microplasma formation was shown to occur as a result of almost complete (up to bare nuclei) ionisation of the initial gas. For the first time the spectral continuum and the dynamics of spectral line formation in the UV and visible spectral ranges were investigated with a picosecond time resolution for the femtosecond laser-produced microplasmas of the air, N2, Ar, and He at normal conditions. For the first time the generation of the second (even) laser radiation harmonic was recorded in a femtosecond subcritical-density plasma of gases.

A “fast,” detonation-like mode of the propagation of an optical discharge with velocities up to 3 km/s is observed in a silica optical fiber at the laser radiation intensity in the core up to 40 W/μm2.

Presented are the experimental results on femtosecond streak tubes measurements in dynamic mode. Several streak tube prototypes have been manufactured, with either distributed coaxial-strip line or capacitor-type photocathode-accelerating mesh assembly. Electrical field transition time in the photocathode-accelerating mesh gap was investigated. Tubes have been tested in a variety of regimes, in order to define the most efficient ones. Dynamic parameters of the developed femtosecond streak tubes were measured inside the streak camera prototype. The following dynamic parameters were evaluated: ultimate time resolution, dynamic range, and signal/noise ratio, spectral range, input sensitivity, streak speed and its nonlinearities, etc. The developed and optimized femtosecond streak tubes represent a reliable basis for design of streak cameras being required for photographic recording of ultrafast events in laser and plasma physics, time-resolved spectroscopy, laser interaction with matter, laser fusion, etc.

We report on time-resolved spectroscopy of femtosecond Laser plasma with the use of ultrafast streak cameras. Laser spark was excited in air, nitrogen, argon or helium by tightly focused Ti: sapphire 130 fs, I mJ, 800 nm single laser pulses. Maximum laser radiation intensity in the focal point was up to 2.5x10(17) W/cm(2). The time behavior of laser plasma continuum, tabulated spectral lines as well as the second and third harmonics were observed with pico-femtosecond time resolution. We believe that the second harmonic generation in femtosecond laser spark was recorded for the first time.