J. Bähr

Measurement of the longitudinal phase space at the Photo Injector Test Facility at DESY Zeuthen

A setup for the measurement of the longitudinal phase space at the photo injector test facility at DESY Zeuthen is described. The measurements of the momentum distribution, the length of an electron bunch and of their correlation are discussed. The results of the momentum distribution measurement are shown, a maximum mean momentum of 4.7 MeV/c and a RMS momentum spread of 14 keV/c is observed. The setup for the measurement of the bunch length includes a Cherenkov radiator which is used to convert the electron beam into a photon beam with a wavelength in the visible range. The Cherenkov radiation mechanism is chosen in order to measure the bunch length with good time resolution. A silica aerogel radiator with low refractive index will be used. Geant 4 simulations show that a resolution of 0.12 ps can be reached. The time dependent behaviour and the position of the photon bunch will be measured by a streak camera system. A simultaneous measurement of the bunch length and the momentum spread will provide the full information about the longitudinal phase space. The design considerations of the radiators and their properties are discussed.

First beam measurements at the photo injector test facility at DESY Zeuthen

The Photo Injector Test facility at DESY Zeuthen (PITZ) was built to develop electron sources for the TESLA Test Facility Free Electron Laser and future linear colliders. The main goal is to study the production of minimum transverse emittance beams with short bunch length at medium charge (∼1 nC). The facility includes a 1.5 cell L-band cavity with coaxial RF coupler, a solenoid for space charge compensation, a laser capable to generate long pulse trains, an UHV photo cathode exchange system, and different diagnostics tools. Besides an overview of the facility, its main components and their commissioning, this contribution will concentrate on the first measurements at PITZ with photoelectrons. This will include measurements of the transverse and longitudinal laser profile, charge and quantum efficiency, momentum and momentum spread, transverse electron beam profiles at different locations and first results on transverse emittance.

RF Commissioning of the Photo Injector Test Facility at DESY Zeuthen

The photo injector test facility at DESY Zeuthen (PITZ) was built to develop, operate and optimize photo injectors for future free electron lasers and linear colliders. First photo electrons were produced in January 2002. An extensive conditioning work on the rf gun has been done in order to achieve high gradients for different pulse lengths and repetition rates. To increase the efficiency and safety aspects of the rf commissioning an Automatic Conditioning Program (ACP) was developed. In addition, a Data Aquisition system (DAQ) which enables a deeper analysis of the commissioning work was realized. The conditioning procedures, the specific diagnostic elements and the achieved results are described. Furthermore, dark current measurements under different conditions are presented.