IHEP Beijing, Beijing
A DC Current Transformer (DCCT) as a standard diagnostic system for beam current plays an important role in BEPCII, the upgrade project of the Beijing Electron Positron Collider. Two DCCTs are operated in the BEPCII storage ring now, separated in electron ring and positron ring, used to monitor the beam current, the beam injection rate and the beam loss rate, meanwhile to help to calculate the beam lifetime. In this paper, the mechanical structure design, readout system and data processing are presented. The progress of DCCTs on each step of BEPCII commissioning, such as improving the beam lifetime，and solution of background noise, are also included.
INFN/LNF, Frascati (Roma)
LAL, Orsay
roma3, Rome
INFN-Roma, Roma
INFN Gruppo di Cosenza, Arcavacata di Rende (Cosenza)
The test of the crabbed waist scheme, undergoing at the Frascati DAΦNE accelerator complex, needs a fast and accurate measurement of the absolute luminosity, as well as a full characterization of the background conditions. Three different monitors, a Bhabha calorimeter, a Bhabha GEM tracker and a gamma bremsstrahlung proportional counter have been designed, tested and installed on the accelerator at the end of January 2008. Results from beam-test measurements, comparison with the Monte Carlo simulation and preliminary data collected during the SIDDHARTA run are presented.
GSI, Darmstadt
LBNL, Berkeley, California
TU Darmstadt, Darmstadt
Non-intercepting Beam Induced Fluorescence (BIF) monitors determine transversal beam profiles by observation of fluorescence light originating from excited residual gas molecules. Thus they are an alternative to conventional intercepting devices. Single photon counting is performed using an image intensified digital CCD camera. We investigated the BIF process in the energy range of 7.7 keV/u to 750 MeV/u in residual nitrogen. Experiments at low beam energies were performed at a Marx-accelerator (NDCX) at Berkeley Lab whereas mid and high energy experiments were carried out at GSI accelerators. Especially in the vicinity of targets the neutron-generated radiation level limits the monitor's signal to background ratio. Therefore the radiation background was investigated for different ion species and particle energies. Background simulations using a Monte Carlo transport code are compared to experimental data measured with scintillators, thermo luminescence detectors and the BIF monitor. Alternative image intensifier techniques are presented as well as shielding concepts. Furthermore the dynamics of ionized nitrogen molecules in the electric field of intense ion beams is discussed.
JLAB, Newport News, Virginia
CASA, newport news
Fermilab, Batavia
An optical diffraction radiation (ODR) diagnostic station was recently designed and installed on a CEBAF transfer beam line. The purpose of the setup is to evaluate experimentally the applicability range for an ODR based non interceptive beam size monitor as well as to collect data to benchmark numerical modeling of the ODR. An extensive set of measurements were made at the electron beam energy of 4.5 GeV. The ODR measurements were made for both pulsed and CW electron beam of up to 80 uA. The wavelength dependence and polarization components of the ODR were studied using a set of insertable bandpass filters (500 nm short and 500 nm long pass filter) and polarizers (horizontal and vertical). The typical transverse beam size during the measurements was ~150 microns. Complete ODR data, wavelength and polarization, were recorded for different beam sizes and intensities. The beam size was also measured with an optical transition radiation (OTR) (using the surface of the ODR converter) and wire scanner located next to the ODR station. In this contribution we describe the experimental setup and present the results of the measurements with the comparison to the numerical simulations.
