16, 18O induced transfer reactions on122, 120Sn

Spieler, H.; Körner, H. J.; Rehm, K. E.; Richter, M.; Rother, H.

doi:10.1007/bf01409174

Cited by 10 publications

(2 citation statements)

References 21 publications

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“…This is similar to the behavior found for other two-neutron transfer reactions. 22,23 Angular distributions for the sum of elastic and inelastic scattering to low-lying states in the Ni isotopes and for the one-neutron transfer reactions ( 58 Ni, 59 Ni) are shown in Fig. 2.…”

Section: Transfer Cross Sections Formentioning

confidence: 99%

Transfer cross sections for58Ni+58
Rehm
¹
,
Wolfs
²
,
Berg
³

et al. 1985
Phys. Rev. Lett.
Self Cite
57
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0
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Transfer cross sections have been measured for 58 Ni + 58 ' 64 Ni in the energy range £ cm . = IOC-107 MeV with use of time of flight in a magnetic spectrograph. The direct reactions are dominated by one-neutron transfer, with other transfer cross sections being smaller by a factor of 3-4 or more. The average kinetic energy loss is -2 MeV. Over the measured energy range the total transfer cross section for 58 Ni + 58 Ni is smaller than that observed for 58 Ni + 64 Ni by a factor of 4.PACS numbers: 25.70.CdMuch of the recent interest in heavy-ion reactions at energies near the Coulomb barrier follows from the large subbarrier fusion cross sections 1 " 9 observed in reactions induced by heavy projectiles {A > 40). Particularly striking are the results for the systems 58 Ni + 58>64 Ni (Ref.3) which revealed a strong isotope dependence in the subbarrier fusion yield. A number of theoretical models have been put forth recently, 10 "" 15 mainly invoking the coupling of quasielastic channels in order to explain the large enhancements of the fusion cross section observed for many systems. While fusion cross sections have now been measured for a variety of heavy systems, only little experimental information is available on the strength of quasielastic reaction channels at energies in the vicinity of the Coulomb barrier. 16 "" 19 It has been argued 11,12 that for 58 Ni + 64 Ni the two-neutron transfer reaction 64 Ni( 58 Ni, 60 Ni) could be responsible for the large enhancement of the subbarrier fusion cross section because of its positive ground state Q value. This paper reports on measurements of the transfer cross sections for the systems 58 Ni + 58 Ni and 58 Ni + 64 Ni at energies in the vicinity of the Coulomb barrier.Attempts to measure the energy dependence of the total strength of heavy-ion transfer reactions at low incident energies have been mainly performed by detection of characteristic y rays of the final nuclei. 16 ' 18 This technique allows the measurement of relative yields in an excitation function, but for the extraction of absolute cross sections a detailed knowledge of the decay scheme of the final nuclei is necessary. In addition, transfer to ground states can in principle not be observed and weak channels are difficult to detect because of background problems. Indeed, a recent y-ray measurement of the reaction 64 Ni( 58 Ni, 59 Ni) 63 Ni encounters these difficulties. When the strength of these transitions, which are easily observed in the y-ray spectra, is extrapolated to deduce the total transfer cross section the results are in disagreement with our charged-particle measurements, as discussed below. The direct detection of the outgoing particles requires a detector capable of detecting and identifying lowenergy beamlike particles at backward angles. For reactions between nuclei with comparable masses one can detect targetlike fragments at forward angles which correspond to beamlike particles scattered backwards. The problem in this case is the large background of elastically scattered beam particle...

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Section: Transfer Cross Sections Formentioning

confidence: 99%

Transfer cross sections for58Ni+58
Rehm
¹
,
Wolfs
²
,
Berg
³

et al. 1985
Phys. Rev. Lett.
Self Cite
57
0
10
0
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“…This is a myth-the no*se of Vis cable can hardly be measured. Cables can introduce ground loops, and pickup of external signaU can -r. significant if shield coverage *s poor and connec tors are poorly mounted 'check yoy cab'es 1 Fig. l^b is free of these 'imitations.…”

Section: G Resistively Terminated Systemsmentioning

confidence: 99%

Fast Timing Methods for Semiconductor Detectors

Spieler

1982

IEEE Trans. Nucl. Sci.

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This tutorial paper discusses the basic parameters which determine the accuracy of timing measurements and their effect in a practical application, specifi cally timing with thin-.surface barrier detectors. The discussion focusses on properties of the detec tor, low-noise amplifiers, trigger circuits and time converters. New material presented in this paper includes bipolar transistor input stages with noise performance superior to currently available FETs, "noiseless" input terminations in sub-nanosecond pre amplifiers and methods using transmission lines to •-,>t;pie the detector to remotely mounted preamplifiers. Trigger circuits are characterized in terms of effec tive rise time, equivalent input noise and residual jitter. 1-INTRODUCTIONFast timing with semiconductor detectors is a many-faceted subject, where the multitude of relevant delays can easily obscure the fact that the perfor mance of aM timing systems is determined by only a few basic principles. The purpose of this tutorial paper is to point out these principles ind demonstrate how the> apply to a specific situation. For clarity this demonstration will be restricted to thin surface ba-rier detectors. This choice is justified by the feet that systems using these detectors not only pro vide the best time resolution currently being obtained with semiconductor detectors, but that they also have the potential for significant improvement.A typical nuclear detector system usinr surface barrier detectors is the AE-E time-of-flight te'escope. Figure 1 shows the basic configuration of such a system: a thin transmission detector (AE) and a stop detector (E) a>-e spaced so that particles pas sing through the sta-*t detector traverse a distance s before impinging on the stop detector. The time-offlight t between the two detectors is measured, which, together with the energy E measured in the stop detecmits calcu^tion of the particle mass: AE DETECTOR E DETECTOR pen•-*-E Time resolution of 50 to 100 ps is being obtained routinely by several experimental groups.^-' In orde* -to recognize and understand the limiting factors in these measurements it is necessary to systematically eva-uate the contributions of all components in the timing system. -SYSTEM COMPONENTS AND BASIC CRITERIAThe basic semiconductor detector timing channel is snown in Fig. 3. Its components a-e: 1. A detector, which produces a c-jri-ent or vo'tage pulse when a particle deposits energy in its sensi tive vo'ume.?. A series of amplifiers, which present the appro priate impedance to the detector and amplify the detector signal by an amount sufficient to drive the trigger circuit.3. A trigger (often called a discriminator}, which furnishes a normalized logic pulse with a well defin ed time relationship to the 'variable) input signal and ultimately to the physical cause of this signa 1 , i.e. the particle impinging on the detector.

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Sub-barrier fusion of o+sn using a new detection system

Tserruya

Jacobs

Breskin

et al.

Fusion Reactions Below the Coulomb Barrier

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16, 18O induced transfer reactions on122, 120Sn

Cited by 10 publications

References 21 publications

Transfer cross sections for58Ni+58
Rehm
¹
,
Wolfs
²
,
Berg
³

et al. 1985
Phys. Rev. Lett.
Self Cite
57
0
10
0
View full text Add to dashboard Cite

Transfer cross sections for58Ni+58
Rehm
¹
,
Wolfs
²
,
Berg
³

et al. 1985
Phys. Rev. Lett.
Self Cite
57
0
10
0
View full text Add to dashboard Cite

Fast Timing Methods for Semiconductor Detectors

Sub-barrier fusion of o+sn using a new detection system

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16, 18O induced transfer reactions on122, 120Sn

Cited by 10 publications

References 21 publications

Transfer cross sections for58Ni+58Rehm1, Wolfs2, Berg3 et al. 1985Phys. Rev. Lett.Self Cite570100View full textAdd to dashboardCite

Transfer cross sections for58Ni+58Rehm1, Wolfs2, Berg3 et al. 1985Phys. Rev. Lett.Self Cite570100View full textAdd to dashboardCite

Fast Timing Methods for Semiconductor Detectors

Sub-barrier fusion of o+sn using a new detection system

Contact Info

Product

Resources

About

Transfer cross sections for58Ni+58
Rehm
¹
,
Wolfs
²
,
Berg
³

et al. 1985
Phys. Rev. Lett.
Self Cite
57
0
10
0
View full text Add to dashboard Cite

Transfer cross sections for58Ni+58
Rehm
¹
,
Wolfs
²
,
Berg
³

et al. 1985
Phys. Rev. Lett.
Self Cite
57
0
10
0
View full text Add to dashboard Cite