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2. |
- Abat, E., et al.
(författare)
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The ATLAS Transition Radiation Tracker (TRT) proportional drift tube: design and performance
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:2
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Tidskriftsartikel (refereegranskat)abstract
- A straw proportional counter is the basic element of the ATLAS Transition Radiation Tracker (TRT). Its detailed properties as well as the main properties of a few TRT operating gas mixtures are described. Particular attention is paid to straw tube performance in high radiation conditions and to its operational stability.
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3. |
- Abat, E., et al.
(författare)
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The ATLAS TRT electronics
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:6
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS inner detector consists of three sub-systems: the pixel detector spanning the radius range 4cm-20cm, the semiconductor tracker at radii from 30 to 52 cm, and the transition radiation tracker (TRT), tracking from 56 to 107 cm. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift tubes (or straws) and of electron identification based on transition radiation from fibres or foils interleaved between the straws themselves. This paper describes the on and off detector electronics for the TRT as well as the TRT portion of the data acquisition (DAQ) system.
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4. |
- Abat, E., et al.
(författare)
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The ATLAS TRT end-cap detectors
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS TRT end-cap is a tracking drift chamber using 245,760 individual tubular drift tubes. It is a part of the TRT tracker which consist of the barrel and two end-caps. The TRT end-caps cover the forward and backward pseudo-rapidity region 1.0 < vertical bar eta vertical bar < 2.0, while the TRT barrel central eta region vertical bar eta vertical bar < 1.0. The TRT system provides a combination of continuous tracking with many measurements in individual drift tubes ( or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. Along with other two sub-systems, namely the Pixel detector and Semi Conductor Tracker (SCT), the TRT constitutes the ATLAS Inner Detector. This paper describes the recently completed and installed TRT end-cap detectors, their design, assembly, integration and the acceptance tests applied during the construction.
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5. |
- Abat, E., et al.
(författare)
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The ATLAS TRT barrel detector
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The ATLAS TRT barrel is a tracking drift chamber using 52,544 individual tubular drift tubes. It is one part of the ATLAS Inner Detector, which consists of three sub-systems: the pixel detector spanning the radius range 4 to 20 cm, the semiconductor tracker (SCT) from 30 to 52 cm, and the transition radiation tracker ( TRT) from 56 to 108 cm. The TRT barrel covers the central pseudo-rapidity region |eta| < 1, while the TRT endcaps cover the forward and backward eta regions. These TRT systems provide a combination of continuous tracking with many measurements in individual drift tubes ( or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. This paper describes the recently-completed construction of the TRT Barrel detector, including the quality control procedures used in the fabrication of the detector.
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6. |
- Cwetanski, P, et al.
(författare)
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Acceptance tests and criteria of the ATLAS transition radiation tracker
- 2005
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499. ; 52:6, s. 2911-2916
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Tidskriftsartikel (refereegranskat)abstract
- The Transition Radiation Tracker (TRT) sits at the outermost part of the ATLAS Inner Detector, encasing the Pixel Detector and the Semi-Conductor Tracker (SCT). The TRT combines charged particle track reconstruction with electron identification capability. This is achieved by layers of xenonfilled straw tubes with periodic radiator foils or fibers providing TR photon emission. The design and choice of materials have been optimized to cope with the harsh operating conditions at the LHC, which are expected to lead to an accumulated radiation dose of 10 Mrad and a neutron fluence of up to 2 . 10(14) n/cm(2) after ten years of operation. The TRT comprises a barrel containing 52 000 axial straws and two end-cap parts with 320 000 radial straws. The total of 420 000 electronic channels (two channels per barrel straw) allows continuous tracking with many projective measurements (more than 30 straw hits per track). The assembly of the barrel modules in the US has recently been completed, while the end-cap wheel construction in Russia has reached the 50% mark. After testing at the production sites and shipment to CERN, all modules and wheels undergo a series of quality and conformity measurements. These acceptance tests survey dimensions, wire tension, gas-tightness, high-voltage stability and gas-gain uniformity along each individual straw. This paper gives details on the acceptance criteria and measurement methods. An overview of the most important results obtained to-date is also given.
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7. |
- Bentley, M. A., et al.
(författare)
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Isospin symmetry of odd-odd mirror nuclei: Identification of excited states in N=Z-2 Mn-48
- 2006
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Ingår i: Physical Review Letters. - 1079-7114. ; 97:13: 132501
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Tidskriftsartikel (refereegranskat)abstract
- Excited states have been observed in the N=Z-2 odd-odd nucleus Mn-48 for the first time. Through comparison with the structure of V-48, a first high-spin study of an odd-odd mirror pair has been achieved. Differences between the T=1 analogue states in this pair have been interpreted in terms of Coulomb effects, with the aid of shell-model calculations in the full pf valence space. Unlike other mirror pairs, the energy differences have been interpreted almost entirely as due to a monopole effect associated with smooth changes in radius (or deformation) as a function of angular momentum. In addition, the large energy shift between analogue negative-parity states is interpreted in terms of the electromagnetic spin-orbit interaction in nuclei.
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8. |
- Aguilar, A, et al.
(författare)
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New shape minimum in Yb-160: Evidence for a triaxial, strongly deformed band
- 2008
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:2, s. 5-021302
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Tidskriftsartikel (refereegranskat)abstract
- A high-spin rotational band was observed in the N=90 nucleus Yb-160 with moment of inertia and decay characteristics very similar to recently discovered sequences in Er-157,Er-158. These latter structures were discussed in terms of strongly deformed triaxial bands. Detailed cranked Nilsson-Strutinsky calculations were performed that predict that well-deformed triaxial structures are also expected at high spin in Yb-160. Within this interpretation the observed discontinuity in the dynamic moment of inertia around h omega=0.40-0.45 MeV can be explained as a crossing between i(13/2) neutron levels.
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9. |
- du Rietz, Rickard, et al.
(författare)
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Investigation of High-spin States in 53Fe
- 2005
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 72:1
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Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reactions Si-28(S-32,1 alpha 2p1n)Fe-53 at 125 MeV and Mg-24(S-32,2p1n)Fe-53 at a 95-MeV beam energy were used to investigate excited states in Fe-53. The combination of the Gammasphere Ge detector array and ancillary devices led to the construction of an extensive level scheme comprising some 90 transitions connecting 40 states. The lifetime of the yrast 25/2(-) state and upper limits for the lifetimes of a number of additional states were determined using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The experimental results are compared to large-scale shell-model calculations using different sets of two-body matrix elements. In particular, predictions on electromagnetic decay properties such as lifetimes, branching ratios, and mixing ratios are studied in detail.
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10. |
- Hammond, G, et al.
(författare)
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Spectroscopy of T=3/2 Mirror Nuclei via Two-step Fragmentation using RISING
- 2005
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 36:4, s. 1253-1257
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Tidskriftsartikel (refereegranskat)abstract
- Two two-step fragmentation reactions were performed using RISING to populate excited states in A approximate to 50 mirror nuclei near to the proton-drip line, in order to test isospin symmetry. The experiments were designed to observe gamma decays of excited states in the mirror nuclei Ni-53(28)25/Mn-53(25)28, which have a large value of total isospin (T = 3/2). In the continuing off-line analysis, gamma transitions have been observed in Ni-54 indicating that two-step fragmentation is a successful technique for spectroscopic investigations of proton-rich nuclear systems in this mass region.
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