IFIC, Valencia, Spain
LLR, Palaiseau, France
The Beam Delivery System of some hadrontherapy facilities is characterized by having scanning magnets, which move the beam in order to irradiate all the tumor volume. To control the beam position, a Beam Position Monitor (BPM) is needed. The BPM described in this paper is a new type of BPM based on four scintillating fibers coupled to four photodiodes to detect the light produced by the fibers when intercepting the beam. We present here the study of the possible photodiodes able to read the light emitted by the scintillating fiber, and the tests performed in order to find the most suitable photodiode to measure the beam position from the variations in the beam current. The setup used for the tests comprises a Sr-90 source, which emits electrons, a scintillating fiber, converting these electrons into photons, and a photodiode, which detects the photons leaving the fiber. The photodiodes studied have been of two types: Avalanche Photodiode (APD) and Multi Pixel Photon Counter (MPPC). In this paper both photodiodes are compared and the results are presented.
IFIC, Valencia, Spain
UVEG, Burjasot (Valencia), Spain
A series of Inductive Pick-Ups (IPU) for Beam Position Monitoring (BPM) with its associated electronics were designed, constructed and tested at IFIC. A full set of 16 BPMs, so called BPS units, were successfully installed in the Test Beam Line (TBL) of the 3rd CLIC Test Facility (CTF3) at CERN. Two different characterization tests, at low and high frequencies, were carried out on the BPS units: The low frequency test, in the beam pulse time scale (until 10ns/100MHz), determined the BPSs parameters directly related to the beam position monitoring and the high frequency test, reaching the microwave X-Ku bands around the beam bunching time scale (83ps/12GHz). In this paper we describe the results and methods used to obtain the longitudinal impedance in the frequency range of interest. This test is based on the S-parameters measurements of the propagating TEM mode in a matched coaxial waveguide, specifically designed for the BPS, which is able to emulate an ultra-relativistic electron beam.
IFIC, Valencia, Spain
SLAC, Menlo Park, California, USA
In this paper we describe the calibration tests, software development and first measurements of a Multi Optical Transition Radiation System in the beam diagnostic section of the Extraction (EXT) line of ATF2, close to the multi wire scanner system. First 2D emittance measurements have been made with success and the system is being used normally for coupling correction. 4D emittance reconstruction algorithm is under improvement and implementation before a systematic measurement campaign and comparison with wire scanners is done. This will be a definitive test of the OTR as a beam emittance diagnostic device, which will give the ability to measure the beam emittance with high statistics, giving a low error and a good understanding of emittance jitter.