| Paper |
Title |
Page |
| MOP36 |
Preliminary Study on HOM-Based Beam Alignment in the TESLA Test Facility
|
117 |
| |
- N. Baboi, G. Kreps, M. Wendt
DESY, Hamburg
- G. Devanz, R. Paparella
CEA/DAPNIA-SACM, Gif-sur-Yvette Cedex
- O. Napoly
CEA/DSM/DAPNIA, Gif-sur-Yvette
|
|
| |
The interaction of the beam with the higher order modes (HOM) in the TESLA cavities has been studied in the past at the TESLA Test Facility (TTF) in order to determine whether the modes with the highest loss factor are sufficiently damped. The same modes can be used actively for beam alignment. At TTF the beam alignment based on the HOM signals is planned to be studied in the first cryo-module, containing 8 accelerating cavities. One of several modes with higher loss factor will be used. Its polarization has to be determined. The options to use single bunches or bunch trains will be analyzed. The results will be discussed in this paper.
|
|
| TUP69 |
Precision Alignments of Stripline BPMs with Quadrupole Magnets for TTF2
|
426 |
| |
- G. Priebe, D. Nölle, M. Wendt, M. Werner
DESY, Hamburg
|
|
| |
We report on our alignment setup to calibrate beam position monitors (BPM) with respect to the magnetic axis of the quadrupole magnets used in the warm sections of the TESLA Test Facility (TTF2). The Stripline BPM's are fixed inside the quadrupole magnets. A streched wire measurement was used to calibrate the electrical axis of the BPM wrt. to the magnetic axis of the quadrupole.
|
|
| TUP71 |
Highly Sensitive Measurements of the Dark Current of Superconducting Cavities for TESLA Using a SQUID Based Cryogenic Current Comparator
|
432 |
| |
- W. Vodel, R. Neubert, S. Nietzsche
FSU, Jena
- K. Knaack, M. Wendt, K. Wittenburg
DESY, Hamburg
- A. Peters
GSI, Darmstadt
|
|
| |
This contribution presents a Cryogenic Current Comparator (CCC) as an excellent tool for detecting dark currents generated, e.g. by superconducting cavities for the upcoming TESLA project (X-FEL) at DESY. To achieve the maximum possible energy the gradient of the superconducting RF cavities should be pushed close to the physical limit of 50 MV/m. The undesired field emission of electrons (so-called dark current) of the superconducting RF cavities at strong fields may limit the maximum gradient. The absolute measurement of the dark current in correlation with the gradient will give a proper value to compare and classify the cavities. The main component of the CCC is a highly sensitive LTS-DC SQUID system which is able to measure extremely low magnetic fields, e.g. caused by the dark current. For this reason the input coil of the SQUID is connected across a special designed toroidal niobium pick-up coil for the passing electron beam. A noise limited current resolution of nearly 2 pA/√(Hz) with a measurement bandwidth of up to 70 kHz was achieved in the laboratory. Design issues of the CCC and the application in the CHECHIA cavity test stand at DESY as well as experimental results will be discussed.
|
|
| TUP72 |
TTF II Beam Monitors for Beam Position, Bunch Charge and Phase Measurements
|
435 |
| |
- M. Wendt, D. Nölle
DESY, Hamburg
|
|
| |
An overview of the basic beam instrumentation with regard to elecromagnetic beam monitors for the TESLA Test Facility phase II (TTF II) is given. Emphasis is put on beam position monitor (BPM) and toroid transformer systems for beam orbit and bunch charge observations. Furthermore broadband monitors, i.e. wall current and bunch phase monitors, are briefly presented.
|
|