IPAC2011 - List of Authors (Panse, R.E.)

Paper

Title

Page

Implementation of an Intensity Feedback-loop for an Ion-therapy Synchrotron

2851

C. Schömers, E. Feldmeier, Th. Haberer, J. Naumann, R.E. Panse, A. Peters
HIT, Heidelberg, Germany

The Heidelberg Ion Therapy-Centre (HIT) started treatment of tumour patients in 2009. Its main acceleration stage is a synchrotron, where particles are extracted slowly, in the time frame of some seconds, to support the raster-scanning method. The slow extraction is driven by the transverse "RF-nockout-exciter". So far, this device has a variable but predefined amplitude curve. As the phase-space distribution of particles is not homogeneous and varies slightly from pulse to pulse, intensity-fluctuations of the extracted beam appear. Moreover, changing accelerator-settings requires a time-consuming re-adjustment of the exciter to achieve adequate beam-properties again. To keep the intensity on a predefined level, a feedback loop will be implemented. The actual-value of the intensity is provided by an ionization chamber in front of the patient. The feedback loop controls the amplitude of the Exciter, to adapt the number of extracted particles. Beside a rectangular spill with constant intensity, a dynamic intensity-adaptation during one spill with respect to the particular treatment-plan will be investigated. First tests for flat spill and variable intensity showed promising results.

Slides THOAA02 [2.284 MB]

Paper	Title	Page
THOAA02	Implementation of an Intensity Feedback-loop for an Ion-therapy Synchrotron	2851
	C. Schömers, E. Feldmeier, Th. Haberer, J. Naumann, R.E. Panse, A. Peters HIT, Heidelberg, Germany
	The Heidelberg Ion Therapy-Centre (HIT) started treatment of tumour patients in 2009. Its main acceleration stage is a synchrotron, where particles are extracted slowly, in the time frame of some seconds, to support the raster-scanning method. The slow extraction is driven by the transverse "RF-nockout-exciter". So far, this device has a variable but predefined amplitude curve. As the phase-space distribution of particles is not homogeneous and varies slightly from pulse to pulse, intensity-fluctuations of the extracted beam appear. Moreover, changing accelerator-settings requires a time-consuming re-adjustment of the exciter to achieve adequate beam-properties again. To keep the intensity on a predefined level, a feedback loop will be implemented. The actual-value of the intensity is provided by an ionization chamber in front of the patient. The feedback loop controls the amplitude of the Exciter, to adapt the number of extracted particles. Beside a rectangular spill with constant intensity, a dynamic intensity-adaptation during one spill with respect to the particular treatment-plan will be investigated. First tests for flat spill and variable intensity showed promising results.
	Slides THOAA02 [2.284 MB]