Contributions to DIPAC 2009 related to Wire Scanners
TUPB05 Fast Wire Scanner Calibration System
A. E. Lokhovitskiy, A. Guerrero, J. Koopman
During the 2008/2009 shutdown the electronics for the Fast Wire-scanners
for the CERN PSB and PS machines will be renovated with new movement and
acquisition electronics. A new test bench was produced that allows
measuring the movement of wires at speeds up to 20 m/s. This poster will
present the calibration system with its related software.
paper: [pdf], poster: [pdf,
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TUPB11 Fast and High Accuracy Wire Scanner
M. Koujili, C. Bal, B. Dehning, J. Koopman, D. Ramos, M. Sapinski
Scanning of a high intensity particle beam imposes challenging requirements
on Wire Scanner system. It is expected to reach scanning speed of 20 m/s with
position accuracy of the order of 1 μm. In addition a timing accuracy better
than 1 millisecond is needed. The adopted solution consists of a wire holding
fork rotating by maximal of 200°. Fork, rotor and angular position sensor are
mounted on the same axis and located in a chamber connected to the beam vacuum.
The requirements imply the design of a system with extremely low vibration,
vacuum compatibility, radiation, and temperature tolerance. The adopted solution
consists of a rotary brushless synchronous motor with the permanent magnet rotor
installed inside of the vacuum chamber and the stator installed outside. The
accurate position sensor will be mounted on the rotary shaft inside of vacuum
chamber and has to resist bake-out temperature of 200°C and ionizing radiation
up to tenth of kGy/years. A digital feedback controller allows maximum
flexibility for the loop parameters and feeds the 3 phases input for the linear
power driver. The paper will present a detail discussion of chosen concept and
the selected components.
paper: [pdf], poster: [pdf]
TUPD40 Carbon Fibre Damage in Accelerator Beam
M. Sapinski, B. Dehning,
A. Guerrero, J. Koopman, E. Métral
Carbon fibres are commonly used as moving targets in Beam Wire Scanners.
Because of their thermo mechanical properties they are very resistant to
particle beams. Their strength deteriorates with time due to low-cycle thermal
fatigue. In case of high intensity beams this process can accelerate and in
extreme cases the fibre is damaged during a scan. In this work a model
describing the fibre temperature, thermionic emission and sublimation is
discussed. Results are compared with fibre damage test performed on the CERN SPS
beam in November 2008. For the operation of Wire Scanners with high intensity
beams damage threshold are predicted.
paper: [pdf], poster: [pdf]
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