| 1. |
- Guidi, Vincenzo, et al.
(författare)
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Selective sublimation processing of thin films for gas sensing
- 2005
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 108:1-2 SPEC. ISS., s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- The selective sublimation processing (SSP) is a useful and easy method for production of semiconducting thin films via reactive sputtering for gas sensing. We have investigated the mechanism of film growth and processing for an insight into the main parameters that control the preparation methodology. A model based on diffusion equation, in the framework of a linear theory, has been proposed and compared to experimental evidences. Rutherford backscattering spectrometry has been extensively used as a tool for determination of concentration profiles in the layers. The model allowed a deeper understanding of film preparation with a physical description of the processes involved, which would open up the design of innovative nanostructured materials that rely on SSP. Titania thin films produced by this methodology and proved capable of sensing target gases of interest for many applications. © 2004 Elsevier B.V. All rights reserved.
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| 2. |
- Scandale, Walter, et al.
(författare)
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Apparatus to study crystal channeling and volume reflection phenomena at the SPS H8 beamline
- 2008
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 79:2
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Tidskriftsartikel (refereegranskat)abstract
- A high performance apparatus has been designed and built by the H8-RD22 collaboration for the study of channeling and volume reflection phenomena in the interaction of 400 GeVc protons with bent silicon crystals, during the 2006 data taking in the external beamline H8 of the CERN SPS. High-quality silicon short crystals were bent by either anticlastic or quasimosaic effects. Alignment with the highly parallel (8 μrad divergence) proton beam was guaranteed through a submicroradian goniometric system equipped with both rotational and translational stages. Particle tracking was possible by a series of silicon microstrip detectors with high-resolution and a parallel plate gas chamber, triggered by various scintillating detectors located along the beamline. Experimental observation of volume reflection with 400 GeVc protons proved true with a deflection angle of (10.4±0.5) μrad with respect to the unperturbed beam, with a silicon crystal whose (111) planes were parallel to the beam. © 2008 American Institute of Physics.
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| 3. |
- Scandale, Walter, et al.
(författare)
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Deflection of 400GeV/c proton beam with bent silicon crystals at the CERN Super Proton Synchrotron
- 2008
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Ingår i: Physical Review Special Topics - Accelerators and Beams. - 1098-4402. ; 11:6
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a detailed study of the deflection phenomena of a 400GeV/c proton beam impinging on a new generation of bent silicon crystals; the tests have been performed at the CERN Super Proton Synchrotron H8 beam line. Channeling and volume reflection angles are measured with an extremely precise goniometer and with high resolution silicon microstrip detectors. Volume reflection has been observed and measured for the first time at this energy, with a single-pass efficiency as large as 98%, in good agreement with the simulation results. This efficiency makes volume reflection a possible candidate for collimation with bent crystals at the CERN Large Hadron Collider. © 2008 The American Physical Society.
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| 4. |
- Scandale, Walter, et al.
(författare)
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Double volume reflection of a proton beam by a sequence of two bent crystals
- 2008
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 658:4, s. 109-111
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Tidskriftsartikel (refereegranskat)abstract
- The doubling of the angle of beam deflection due to volume reflection of protons by a sequence of two bent silicon crystals was experimentally observed at the 400 GeV proton beam of the CERN SPS. A similar sequence of short bent crystals can be used as an efficient primary collimator for the Large Hadron Collider.
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| 5. |
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| 6. |
- Vomiero, Alberto, et al.
(författare)
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Structure and morphology of surface of silicon crystals to be applied for channeling at relativistic energies
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section B. - : Elsevier BV. - 0168-583X .- 1872-9584. ; 249:1-2 SPEC. ISS., s. 903-906
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Tidskriftsartikel (refereegranskat)abstract
- Bent crystals can be successfully applied for extraction/collimation of relativistic particles. A crucial feature to obtain high extraction efficiencies is the treatment of the surfaces being encountered by the beam, since mechanical operations induce considerable lattice imperfections. In order to remove the superficial damaged layer a planar etching can be applied on the surface exposed to the beam. This work presents a systematic study of the morphology and the crystalline perfection of the surface of the samples that have been used in accelerators with high efficiency. Crystals with different surface treatments have been investigated. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were applied on the characterisation of surface morphology. Low energy backscattering channeling of 2-MeV α particles or protons was used as a probe for the crystalline structure. The presence of a superficial damaged layer in the samples just after mechanical treatment was unveiled, while, in contrast, chemical etching leaves a surface with high crystalline perfection that can be related to the record efficiency. © 2006 Elsevier B.V. All rights reserved.
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