Proton extraction from the CERN SPS using bent silicon crystals Elsener, K.; Fidecaro, G.; Gyr, M. ...
Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms,
10/1996, Letnik:
119, Številka:
1
Journal Article
Recenzirano
The extraction of high energy particles from a circular accelerator by means of channeling in bent crystals is an attractive alternative to classical extraction schemes, in particular for high energy ...proton colliders where a classical scheme becomes expensive and incompatible with normal operation. This paper reviews the ongoing extraction experiments at the CERN-SPS with bent silicon crystals. It describes the principles of beam extraction by means of a bent crystal and the different extraction schemes used: first- and multi-pass extraction and the methods to create diffusion. The limitations in tuning the accelerator to the desired impact parameters and crucial items concerning crystal preparation, bending and pre-alignment are discussed. The experimental procedures including an overview of the detection of circulating and extracted beam are given. Finally, the paper summarizes the results of these experiments together with ideas for future developments.
Recent measurements of 120 GeV proton extraction by means of a bent silicon crystal at the CERN-SPS accelerator are summarized. The existence of multi-pass extraction has been proven by blocking ...first-pass extraction: using a crystal covered with an amorphous layer, extracted beam with high efficiency was observed, which provides a direct proof for the importance of the multi-pass mechanism. This opens new possibilities in the design and optimization of a bent crystal extraction scheme.
Position sensitive photomultipliers coupled to scintillating fibers allow the construction of compact and fast particle tracking detectors. We describe a detector based on these techniques, and ...discuss its measured performances. Efficiency, space resolution and the effects of cross-talk between neighboring channels are studied in detail.
Radiation hardness and monitoring of the BaBar vertex tracker Re, V.; Bruinsma, M.; Kirkby, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2/2004, Letnik:
518, Številka:
1-2
Journal Article
In this paper the studies of three different B decays to hadronic states are
presented. These results are based on 1999-2003 dataset collected by the BaBar
experiment at the PEP-II e+e- storage ring ...at the Stanford Linear Accelerator
Center. The measurements are the hadronic branching fraction of B+ -> J/psi p
Lambda-bar, B0 -> J/psi p p-bar, B0 -> D*+D-, and the direct CP-asymmetry in B0
-> D0(CP) K- channels.
The BaBar Silicon Vertex Tracker is a five layers, double sided AC-coupled silicon microstrip detector operating on the PEP-II storage ring at the Stanford Linear Accelerator Center. The performance ...of the SVT after 4 years of running is described. Results from radiation hardness tests are presented and the implications of the absorbed radiation dose on the SVT lifetime are discussed.
Radiation damage studies for the B aB ar Silicon Vertex Tracker Re, V.; Kirkby, D.; Bruinsma, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2005, Letnik:
549, Številka:
1
Journal Article
Recenzirano
The Silicon Vertex Tracker of the
B
aB
ar
experiment is a five-layer, double-sided AC-coupled silicon microstrip detector operating on the PEP-II storage ring at the Stanford Linear Accelerator ...Center. After more than four years of running, the silicon sensors and the front-end electronics in the inner layer have absorbed radiation doses up to 2
Mrad. In this paper we present results from radiation hardness tests and discuss the implications of the absorbed radiation dose on the Silicon Vertex Tracker lifetime.
The BABAR silicon vertex tracker (SVT) has been in operation for four years at the PEP-II electron-positron storage ring. During this time the SVT modules have accumulated a radiation dose up to 2 ...Mrad. We study the degradation in the performance of the SVT due to this accumulated dose which is highly non uniform across the device and also within the individual silicon detectors. To extrapolate the performance of the device to the future we study separately the effect of the irradiation on silicon detectors, front end integrated circuits and on a complete detector module under controlled radiation conditions, using a /sup 60/Co source and a 0.9 GeV e/sup -/ beam. We compare the results to the data from the SVT. In particular we show the dependence of the charge collection efficiency on the radiation dose even when a small stripe of the module is irradiated up to space charge sign inversion. Since the modules that are located in the plane of the beams will suffer significant radiation damage, we will describe our plans for their replacement in 2005 and for the operation of the SVT through the lifetime of the BABAR experiment.
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