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).
A dissector is an electron-optical device designed for measurement of periodic light pulses of subnanosecond and picosecond duration. LI-602 dissector developed at Budker Institute of Nuclear Physics (BINP SB RAS) is widely used for routine measurements of a longitudinal profile of electron and positron beams at BINP electron-positron colliders and other similar installations(1,2). LI-602 dissector is a part of many optical diagnostic systems and provides temporal resolution of about 20 ps. Recently a new generation of picosecond dissectors were created on the basis of the PIF- 01/S1 picosecond streak-image tube designed and manufactured at the A.M.Prokhorov General Physics Institute (GPI) Photoelectronics Department(3,4). The results of the measurements of instrument function of the new dissector based on PIF-01/S1, which were carried out in the static mode(5) showed that temporal resolution of the dissector can be better than 3-4 ps (FWHM). The results of temporal resolution calibration of the new-generation picosecond dissector carried out at the specialized set-up based on a femtosecond Ti:sapphire laser and recent results of longitudinal beam profile measurements at BINP damping ring are given in this work.
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.
Recently a new generation of picosecond dissectors were created on the basis of the PIF-01/S1 picosecond streak-image tube designed and manufactured at the GPI Photoelectronics Department. The results of the measurements of instrument characteristics of the new dissector, which were carried out in the static mode, showed that temporal resolution of the dissector can be better than 3-4 ps (FWHM). The results of temporal resolution calibration of the new-generation picosecond dissector carried out at the specialized set-up based on a femtosecond Ti:sapphire laser are given in this work.
When replacing the conventional “slow” luminescent screens (P20, P43) in picosecond image tubes by the “fast” ones (P46, P47), we found an increase in the decay time of “fast” cathodoluminophors (by a factor of 2–5) with increasing the number (from one to a hundred) of measured pulses. The consideration of the detected effect makes it possible to correct the problem statement in developing picosecond dissectors for recording repeated signals in the accumulation mode (e.g., synchrotron radiation).
Numerical modelling is used to analyse some effects restricting the enhancement of temporal resolution into the area better than 100 fs in streak image tubes and photoelectron guns. A particular attention is paid to broadening of an electron bunch as a result of Coulomb interaction. Possible ways to overcome the limitations under consideration are discussed.
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.
Sciences Division of the Russian Academy of Sciences (RAS) was held at the conference hall at the Lebedev Physical Institute, RAS. The agenda of the session announced on theRASPhysical Sciences Division website www.gpad.ac.ru included the following reports: (1) Schelev M Ya (Prokhorov General Physics Institute, RAS, Moscow) ``Pico-femto-attosecond photoelectronics''; (2) Dal'karov O D (Lebedev Physical Institute, RAS, Moscow) ``The physics of low-energy antiprotons and antimatter''; (3) Polukhina N G (Lebedev Physical Institute, RAS, Moscow) ``Nuclear track detection: advances and potential in astrophysics, particle physics, and applied research''; (4) Vedeneev S I (Lebedev Physical Institute, RAS, Moscow) ``High-temperature superconductors in high and ultrahigh magnetic fields''. Papers written on the base of reports 1, 3, and 4 are presented below.
The information about the congresses held in Japan and devoted to fast imaging processes and photonics is presented. Reports devoted to the technique and the results of applications of superhigh-speed recording instrumentation in different fields of science and technology are considered.
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.
Numerous steps in designing an experimental prototype of a versatile pico-femtosecond streak camera are overviewed. After creation a sub-100fs streak tube with electrostatic focusing lens our main efforts were concentrated on appropriate pulse circuitries design capable to provide low delay/jitter (10 ns, 10ps) at tens of mW input triggering power level, as well as a wide range of streak speeds varying from 108 cm/s to 1011 cm/s. A special input relay optics with "build-up" time shorter than 100fs was also developed. Sub-10 fs laser palses from Femtosource Synergy oscillator ("Femto- Lasers", Austria) was employed for dynamic tests of the created sub-100fs image tubes and cameras.
In the present communication we describe the design of the sub-100 fs streak-tube that may be used for commercial streak cameras manufacturing. Careful attention is paid to preparing of a very smooth input photocathode substrate on which a low surface resistance (1-5 Ohm/) photocathode of S-1 type is deposited. Our estimations have shown that the photocathode surface roughness of about tens of nanometers may restrict the ultimate time resolution at the level of 100 fs. This is the reason why the photocathode substrate surface has to be smooth within the units of nanometers. The curvature of the photocathode surface is also very important to compensate the difference in the time-of-flight of electrons emitted from the central and peripheral photocathode areas. Further modernization was conducted with a photocathode-accelerating mesh assembly. The assembly may operate with 2 - 3 ns (FWHM) electrical pulses of 12 - 15 kV amplitude. In order to improve the S/N ratio in the streaked images, a shuttering system was incorporated inside the tube. As the result, a completely new femtosecond streak tube of PV-FS-M type was designed, manufactured, and tested.
The paper reports on the development of a new streak image tube with accelerating mesh and large (18 mm) photocathode work area. The tube's temporal resolution is close to one picosecond. To govern photoelectronic images the tube possesses shutter and deflector plates. Its geometric design allows uniform spatial resolution (more than 25 lp/mm) along the entire photocathode work area at 1.3 electron-optical magnification and negligibly small distortion. Being a continuation of the well-known PV and PIF - type streak image tubes developed in due time in GPI, the tube represents a promising tool for taking pictures of ultrafast processes in wide radiation spectrum range.
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.
In contrast to the conventional image intensifier with large work area, a streak image tube should possess additional important feature - the comparatively small temporal distortion at the entire work area of the photocathode. With this additional engineering restriction taken into account, a novel small-size meshless streak image tube has been developed by means of numerical optimization. The tube with 25-mm wide work area contains a pair of deflection plates to sweep the electron image along the 25 mm output phosphor screen that is separated by 100 mm from the photocathode. The electron image can be shuttered with a 300 V blanking electric pulse. Electron-optical magnification of the tube is unit; spatial resolution reaches 30 lp/mm over the entire photocathode work area; temporal resolution lies in the 20 - 50 ps range, depending on the accelerating voltage (6 - 15 kV).