Beam position monitors inside the FEL-undulator at the TESLA Test Facility Linac

“…For more complex structures one has to use 3D codes such as MAFIA. The total loss factor k all (all excited modes of a certain azimuthal symmetry) gives also the power deposited in the cavity, P l : P l = k all f av q 2 with f av = N bunches f rep : (24) Example 3: Diagnostic stations for the TESLA Test Facility Linac-FEL Circular cavities were chosen for this purpose [13] because of the required single bunch resolution of 1 m. Since V in 110 is proportional to the cavity size, the TM 110 design frequency is 12 GHz (see Fig. 9b A complete monitor consists of two cavities separated in beam direction.…”

Section: Wakeeldsmentioning

confidence: 99%

Cavity beam position monitors

Lorenz¹

1998

AIP Conference Proceedings

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Abstract. Beam-based alignment and feedback systems are essential for the operation of future linear colliders and free electron lasers. A certain number of beam position monitors with a resolution in the submicron range are needed at selected locations. Most beam position monitors detect the electric or the magnetic eld excited by a beam of charged particles at dierent locations around the beam pipe. In resonant monitors, however, the excitation of special eld congurations by an o-center beam is detected. These structures oer a large signal per micron displacement. This paper is an attempt to summarize the fundamental characteristics of resonant monitors, their advantages and shortcomings. Emphasis will be on the design of cylindrical cavities, in particular on the estimation of expected signals, of resolution limits and the resulting beam distortion. This includes also a short introduction into numerical methods. Fabrication, tuning, and other practical problems will be reviewed briey. Finally, some resonant devices used for beam position diagnostics will be discussed and listed.

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“…All components are controlled by a PC running a Labview application. First, the wire was moved on a 1 mm square around a point close to the electrical center with a stepwidth of 10 m. With these data, three calibration algorithms were tested to obtain the signals functions S x and S y in Equation 3. The results for a range of 400 m from the electrical center are shown in Figure 3b.…”

Section: Measurements In the Laboratorymentioning

confidence: 99%

New microwave beam position monitors for the TESLA test facility—FEL

Kamps¹,

Lorenz²

1998

AIP Conference Proceedings

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Abstract. Beam-based alignment is essential for the operation of the SASE-FEL at the TESLA Test Facility Linac. In order to ensure the overlap of the photon beam and the electron beam, the position of the electron beam has to be measured along the undulator beamline with a high resolution. Due to the severe space limitations, a new microwave concept is being considered. It is based on special ridged waveguides coupling by small slots to the magnetic eld of the electron beam. The four waveguides and slots of each monitor were split into two symmetric pairs separated in beam direction. All waveguides are about 35 degrees apart in azimuth from the horizontal axis and will be fabricated using electro-discharge machining EDM. Waveguide-to-coax adaptors were designed to couple the signal of each waveguide into a coaxial cable. The goal is to measure the averaged position of a bunch train in a narrowband receiver with a center frequency of 12 GHz. A prototype of this monitor was built and tested on a testbench, as well as at the CLIC Test Facility at CERN. The paper summarizes the concept, the design, and further improvements of the waveguide monitor.

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Beam position monitors inside the FEL-undulator at the TESLA Test Facility Linac

Cited by 5 publications

References 2 publications

Design and performance of the vacuum chambers for the undulator of the VUV FEL at the TESLA test facility at DESY

Design and performance of the vacuum chambers for the undulator of the VUV FEL at the TESLA test facility at DESY

Cavity beam position monitors

New microwave beam position monitors for the TESLA test facility—FEL

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