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| 2. |
- Carlén, Lars, et al.
(författare)
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Dynamical. and statistical fragment emission properties in 200 A MeV Ne-20+Ar-40 collisions
- 2006
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Ingår i: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 764, s. 15-23
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Tidskriftsartikel (refereegranskat)abstract
- Dynamical and statistical fragment emission processes in 200 A MeV Ne-20 + Ar-40 collisions are well probed by measurements of charge (Z), mass (A) and momentum vector ((p) over right arrow) of all fragments in large parts of the available momentum space. We present such data obtained at the cluster-jet target of the CELSIUS storage ring, for the first time with an internal, ultra-high vacuum (UHV) compatible detector system (CHICSi). Energy and angular dependence in Z and A distributions are not reproduced by a single-step model, e.g., those based on molecular dynamics (MD), but require a complete three-step model. We use here the intranuclear cascade+ statistical multifragmentation + secondary evaporation model (CFEM). The angular dependence of isobaric ratios, like He-6/Li-6 at low emission velocities and temperatures extracted from isotopic (double) ratios, do exhibit differences, even from this model. These differences, which call for adjustment of model parameters, are discussed. (c) 2005 Elsevier B.V. All rights reserved.
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| 3. |
- Peterson, D, et al.
(författare)
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Direct observation of first-chance fission of No-258
- 2009
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:4, s. 044607-
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Tidskriftsartikel (refereegranskat)abstract
- The multiplicities, angular correlations, and energy spectra of the neutrons associated with fission were measured for the reactions of Mg-25,Mg-26 + Th-232 at Mg-25 and Mg-26 projectile energies of 132 and 148 MeV, respectively. From these data, we extracted a value of Gamma(n)/Gamma(f) for the first-chance fission of No-258 at an excitation energy of 61 MeV. The implications of this result for understanding the survival probabilities of excited heavy nuclei formed in "hot" fusion reactions are discussed.
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| 4. |
- Westerberg, L, et al.
(författare)
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CHICSi - a compact ultra-high vacuum compatible detector system for nuclear reaction experiments at storage rings. I. General structure, mechanics and UHV compatibility
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 500:1-3, s. 84-95
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Tidskriftsartikel (refereegranskat)abstract
- CELSIUS Heavy-Ion Collision Silicon detector system (CHICSi) is a large solid angle, barrel-shaped detector system, housing up to 600 detector telescopes arranged in rotational symmetry around the beam axis. CHICSi measures charged particles and fragments from nuclear reactions. It operates at internal targets of storage rings. In order to optimize space and momentum-space coverage and minimize the low-energy detection limits, CHICSi is designed for use in ultra-high vacuum (UHV, similar to 10(-8) Pa) inside a cluster-jet target chamber. This calls for materials in mechanical support, detectors, Very Large Scale Integrated (VLSI) electronics, connectors, cables and other signal transport devices with very low outgassing. Two auxiliary detector systems, which will operate in coincidence with CHICSi, a heavy-recoil, time-of-flight system (HR-TOF) also placed inside the target chamber and a projectile fragmentation wall (PF-WALL) located outside the chamber, have also been constructed. In total, this combined system registers more than 80% of all charged particles and fragments from typical heavy-ion reactions at energies of a few hundreds of MeV per nucleon. (C) 2003 Elsevier Science B.V. All rights reserved.
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