We present single-shot measurements of the longitudinal bunch profile from a laser-wakefield accelerator with sub-fs resolution, based on detection of coherent transition radiation in a broad spectral range. A previously developed phase retrieval algorithm enables reconstruction of the bunch profile without prior assumptions about its shape. In this study, a variable-length gas target is used t...

ThomX is a high flux compact X ray source based on Compton back scattering between a relativistic electron beam and an intense laser pulse. To increase the repetition rate, the electron beam is stored in a 50 MeV ring. The main drawback of such a scheme is the low energy of the electrons regarding collective effects and intrabeam scattering. These effects tend to spread or even disrupt the stor...

Recent advances in laser wakefield acceleration demonstrated the generation of extremely short (with a duration of a few femtoseconds) relativistic electron bunches with relatively low (of the order of couple of percent) energy spread. In this article we study the dynamics of such bunches in drift space (vacuum) and in channel-guided laser wakefields. Analytical solutions were found for the tra...

The generation of an isolated attosecond gamma-ray pulse utilizing Compton backscattering of a relativistic electron bunch has been investigated. The energy of the electron bunch is modulated while the electron bunch interacts with a co-propagating few-cycle CEP (carrier envelope phase)-locked laser in a single-period wiggler. The energy-modulated electron bunch interacts with a counter-propaga...

A femtosecond electron bunch is essential for the observation of ultrafast phenomena. In order to improve the time resolution of pulse radiolysis and ultrafast electron diffraction (UED), that involve the use of an ultrashort electron bunch and ultrashort light, a femtosecond photocathode RF gun was investigated experimentally. The bunch length due to space-charge and RF effects in the gun was ...

Nonlinear dynamics of the one-dimensional ultrarelativistic bunch of electrons,moving in cold plasma,is considered in multiple scales perturbative approach.A square root of the inverse Lorentz factor of the bunch electrons is taken as a small parameter.Bunch electrons momenta is changed in the first approximation.In the underdense plasma and for the model example of the combined bunch the selfa...

We estimate the short-range wake elds in the W-band active matrix linac of a 5-TeV collider, and demonstrate that for the assumed 60-pC bunch c harge and 10-m rms bunch length they are acceptable. Abstract. We estimate the short-range wake elds in the W-band active matrix linac of a 5-TeV collider, and demonstrate that for the assumed 60-pC bunch c harge and 10-m rms bunch length they are accep...

The beam-beam interaction in the Tevatron collider sets limits on bunch intensity and luminosity. These limits are caused by a tune spread in each bunch which is mostly due to head-on collisions, but there is also a bunch-to-bunch tune spread due to parasitic collisions in multibunch operation. We propose to compensate these effects with use of a countertraveling electron beam, and present gene...

We present the design, performance, and recent upgrade of a high-resolution, highcharge-sensitivity imaging camera and beam position monitor (BPM) system for the APS linac beam profile measurement. Visible light is generated from the incoming electron beam using standard YAG or optical transition radiation (OTR) converter screens. Two CCD cameras share the light through a beam splitter, each wi...

After the successful operation of FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source), soft and hard X-ray Free Electron Lasers (FELs) are being built, designed or proposed at many accelerator laboratories. Acceleration employing lower frequency RF cavities, ranging from L-band to C-band, is usually adopted in these designs. In the first stage bunch compression, higher...