| 1. |
- Fritioff, T., et al.
(författare)
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Purification of radioactive neutron-rich argon beams using an ion source in charge breeding mode
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 556:1, s. 31-37
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of nuclear properties of some neutron-rich asymmetric fission isotopes at an ISOL laboratory present a severe problem when a plasma ion source is used as the primary ion-source. The problem is associated with intense multi-charged symmetric fission contaminants that cannot be mass-separated from asymmetric fission products. In this work we demonstrate how this problem can be overcome on-line by using an electron cyclotron resonance ion source (ECRIS) as a charge-breeding secondary ion-source. Mixed Ar+/Kr2+/Xe3+ radioactive beams from an plasma ion-source were injected into the PHOENIX ECRIS that currently is installed at the ISOLDE facility at CERN in order to improve the ratio of Ar to the background contaminants of Kr and Xe. The signal to noise ratio was improved by more than two orders of magnitude after charge-breeding and mass-separation of the Ar8+, Ar9+ beams. The information on the decay of the Ar-48 nucleus obtained in these tests is useful for a better understanding of the origin of the Ca-48/Ca-46 meteorite isotopic anomaly. Potential applications of the method are discussed.
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| 2. |
- Hidvegi, Attila, et al.
(författare)
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A system for distributing high-speed synchronous high-precision clock and trigger data over large distances
- 2008
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Ingår i: Nuclear Science Symposium Conference Record, 2008. NSS '08. IEEE. - 9781424427147 ; , s. 2581-2584
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Konferensbidrag (refereegranskat)abstract
- The distribution of precise timing throughout the European X-ray Free Electron Laser project [1] (XFEL) and its triggering system is a very challenging part of the system design. ADCs in data acquisition systems and DACs in control systems will require very high precision clocks. The clocks need to be synchronous to each other, both in frequency and phase, with a jitter performance better than 5 ps (RMS). At some high-speed ADCs it might even need a precision down to 0.1 ps. The frequencies that must be available are the main 1.3 GHz and some frequencies below, which are all derived from the main frequency. The phase needs to be adjustable to allow synchronization between separate devices. Triggering information needs to be distributed over the system, so that controlling instructions can be carried out at a very precise time. This is very important since the beam will travel with the speed of light, and there is no possibility for information to be sent back and forth. This requires an absolute timing to be distributed over the system. Both the main clock and triggering information will be transmitted over the same fiber cable, one to each device. An advanced synchronization method needs to be developed to synchronize the phases of the clocks throughout the whole system. The delay through the cable can change with temperature, and due to long cables the total change through a single cable can be significant. It is essential that the clocks are stable and not drifting away from each other. Therefore a continuous calibration method is needed, ensuring that the clocks are synchronous throughout the whole system. A prototype of such a system is being developed and a first version is expected to be completed in 2009 Ql.
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| 3. |
- Abat, E., et al.
(författare)
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Study of the response of the ATLAS central calorimeter to pions of energies from 3 to 9 GeV
- 2009
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002 .- 1872-9576. ; 607:2, s. 372-386
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Tidskriftsartikel (refereegranskat)abstract
- A fully instrumented slice of the ATLAS central detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. in this paper, the response of the central calorimeters to pions with energies in the range between 3 and 9 GeV is presented. The linearity and the resolution of the combined calorimetry (electromagnetic and hadronic calorimeters) was measured and compared to the prediction of a detector simulation program using the toolkit Geant 4. (C) 2009 Elsevier B.V. All rights reserved.
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| 4. |
- Björneholm, Olle, et al.
(författare)
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Free clusters studied by core-level spectroscopies
- 2009
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 601:1-2, s. 161-181
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Forskningsöversikt (refereegranskat)abstract
- In this review we describe the development and current status of free clusters studied using core-level spectroscopies. This topic ranges from simple model systems, such as rare gas clusters, to molecular clusters, and clusters of solids, held together by ionic, covalent and metallic bonding.
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| 5. |
- Murin, Yu., et al.
(författare)
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A detector system for studying nuclear reactions relevant to Single Event Effects
- 2007
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576 .- 0167-5087. ; 578:2, s. 385-398
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Tidskriftsartikel (refereegranskat)abstract
- We describe a device to study reactions relevant for the Single Event Effect (SEE) in microelectronics by means of 200A and 300AMeV, inverse kinematics, Si + H and Si + D reactions. The work is focused on the possibility to measure Z = 2-14 projectile fragments as efficiently as possible. During commissioning and first experiments the fourth quadrant of the CELSIUS storage ring acted as a spectrometer to register fragments in two planes of Si strip detectors in the angular region 0 degrees-0.6 degrees. A combination of ring-structured and sector-structured Si strip detector planes operated at angles 0.6 degrees-1.1 degrees. For specific event tagging a Si+ phoswich scintillator wall operated in the range 3.9 degrees-11.7 degrees and Si Delta E-E telescopes of CHICSi type operated at large angles.
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| 6. |
- McHugo, S. A., et al.
(författare)
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Nanometer–scale metal precipitates in multicrystalline silicon solar cells
- 2001
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 89:8, s. 4282-4288
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we have utilized characterization methods to identify the nature of metal impurityprecipitates in low performance regions of multicrystalline silicon solar cells. Specifically, we haveutilized synchrotron-based x-ray fluorescence and x-ray absorption spectromicroscopy to study theelemental and chemical nature of these impurity precipitates, respectively. We have detectednanometer-scale precipitates of Fe, Cr, Ni, Cu, and Au in multicrystalline silicon materials from avariety of solar cell manufacturers. Additionally, we have obtained a direct correlation between theimpurity precipitates and regions of low light-induced current, providing direct proof that metalimpurities play a significant role in the performance of multicrystalline silicon solar cells.Furthermore, we have identified the chemical state of iron precipitates in the low-performanceregions. These results indicate that the iron precipitates are in the form of oxide or silicatecompound. These compounds are highly stable and cannot be removed with standard siliconprocessing, indicating remediation efforts via impurity removal need to be improved. Futureimprovements to multicrystalline silicon solar cell performance can be best obtained by inhibitingoxygen and metal impurity introduction as well as modifying thermal treatments during crystalgrowth to avoid oxide or silicate formation.
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| 7. |
- Aguilar, A., et al.
(författare)
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Double photodetachment from the Cl[-]ion
- 2004
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Ingår i: Physical Review A - Atomic, Molecular, and Optical Physics. - 2469-9926 .- 2469-9934. ; 69:2
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Tidskriftsartikel (refereegranskat)abstract
- The correlated process involving the photodetachment of two electrons from the [Formula Presented] ion has been investigated over the photon energy range 20–45 eV. In the experiment, a beam of photons from the Advanced Light Source (ALS) was collinearly merged with a counterpropagating beam of [Formula Presented] ions from a sputter ion source. The [Formula Presented] ions produced in the interaction region were detected, and the normalized signal was used to monitor the relative cross section for the reaction. An absolute scale for the cross section was established by measuring the spatial overlap of the two beams and by determining the efficiency for collection and detection of the [Formula Presented] ions. The overall magnitude and shape of the measured cross section for this process agrees well with an R-matrix calculation. The calculation identifies the dominant mechanism leading to the production of the [Formula Presented] ion as being a direct nonresonant process involving the ejection of a pair of electrons from the valence shell. Less important is the indirect nonresonant process that involves the production and decay of core-excited and doubly excited states of the Cl atom in an intermediate step. Direct and indirect resonant mechanisms involving the excitation of a single [Formula Presented] core electron or more than one valence electron of the [Formula Presented] ion were found to be insignificant in the energy range studied.
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| 8. |
- De Oliveira Santos, F., et al.
(författare)
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Study of 19Na at SPIRAL
- 2005
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 24:2, s. 237-247
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Tidskriftsartikel (refereegranskat)abstract
- The excitation function for the elastic-scattering reaction p( 18 Ne, p) 18 Ne was measured with the first radioactive beam from the SPIRAL facility at the GANIL laboratory and with a solid cryogenic hydrogen target. Several broad resonances have been observed, corresponding to new excited states in the unbound nucleus 19 Na. In addition, two-proton emission events have been identified and are discussed.
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| 9. |
- Aad, G., et al.
(författare)
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The ATLAS Experiment at the CERN Large Hadron Collider
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08003
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Forskningsöversikt (refereegranskat)abstract
- The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.
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| 10. |
- Bengtsson, Lars, 1963
(författare)
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Elektriska mätsystem och mätmetoder
- 2003
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Elektrisk mätteknik spänner över ett brett teknikområde och har utvecklats till något av ett tvärtekniskt ingenjörsämne. Den här boken tar fasta på detta och behandlar en lång rad aspekter på elektriska mätsystem och mätmetoder. Boken innehåller t ex en detaljerad genomgång av givare, förstärkare och AD-omvandlare. Mätinstrument med inbyggda signalbehandlingsfunktioner som t ex frekvensanalys, korrelation och medelvärdesbildning utgör en stor del av innehållet. Även filter, både analoga och digitala behandlas. Mätinstrumentens och anslutningskablarnas inverkan på mätvärdet behandlas detaljerat liksom elektromagnetisk störningskoppling och EMC-aspekter på mätsystem, smat databehandling i form av mätosäkerhetsanalyser och kurvanpassning. I boken finns också en presentation av det grafiska programspråket LabVIEW.
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