Experiment planning

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(Created page with "The GOSIA suite of codes are ideally suited to the design and planning of heavy-ion induced Coulomb excitation experiments as well as the subsequent analysis. Coulomb excitation ...")
 
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The GOSIA suite of codes are ideally suited to the design and planning of
The GOSIA suite of codes are ideally suited to the design and planning of
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heavy-ion induced Coulomb excitation experiments as well as the subsequent
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low-energy heavy-ion induced Coulomb excitation experiments as well as the subsequent
analysis. Coulomb excitation experiments can seem deceptively simple,
analysis. Coulomb excitation experiments can seem deceptively simple,
especially for few-state problems, leading some experimenters to fall into  
especially for few-state problems, leading some experimenters to fall into  
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on heavy-ion induced Coulomb excitation.<ref>K. Alder and A. Winther, ''Electromagnetic Excitation: Theory of Coulomb Excitation with Heavy Ions,'' North Holland, Amsterdam (1975).</ref><ref>D. Cline, Ann. Rev. Nucl. Part. Sci. 36:683 (1986).</ref>
on heavy-ion induced Coulomb excitation.<ref>K. Alder and A. Winther, ''Electromagnetic Excitation: Theory of Coulomb Excitation with Heavy Ions,'' North Holland, Amsterdam (1975).</ref><ref>D. Cline, Ann. Rev. Nucl. Part. Sci. 36:683 (1986).</ref>
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==Safe bombarding energy==
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==Experimental parameter considerations==
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===Safe bombarding energy===
The basic assumption of Coulomb excitation is that the interaction between the
The basic assumption of Coulomb excitation is that the interaction between the
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scattering cross sections at large scattering angles in a manner that mimics
scattering cross sections at large scattering angles in a manner that mimics
the reorientation effect corresponding to a negative static quadrupole moment.
the reorientation effect corresponding to a negative static quadrupole moment.
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Chapter 2 of the Gosia manual discusses the issue of safe bombarding energy in detail.
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===The semiclassical approximation===
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The long range of the Coulomb interaction, coupled with the small integrationstep size necessitated by the short wavelength, and the large number of
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partial waves that make significant contributions, conspire to make it
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impractical to use fully quantal codes with current computers that are capable
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of handling the large number of coupled channels important to heavy-ion
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induced Coulomb excitation. Fortunately a considerable simplification
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can be achieved by assuming a semiclassical treatment of two-body
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kinematics as pioneered by Alder and Winther.<ref>K. Alder, A. Winther, K. Dan. Vidensk et al., Mat. Fys. Medd. 32, Number 8 (1960).</ref>
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The semiclassical picture exploits the fact that the monopole-monopole Coulombinteraction <math>Z_1 Z_2 e^2/r</math>
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dominates and determines the relative motion of the two colliding nuclei.
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The semiclassical picture assumes that the size of the
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incoming projectile wavepacket is small compared to the
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dimensions of the classical hyperbolic trajectory which is
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expressed in terms of the [[Sommerfeld_parameter | Sommerfeld parameter]].
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==Simulation==
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Gosia can be used to estimate the sensitivity to a particular matrix element or set of matrix elements that will be obtained in a planned experiment and to optimize the experiment for a desired measurement.  Refer to the [[Simulation_(experiment_planning) | Simulation]] page for more detail.
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==Planning tools==
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While Gosia is the obvious tool for planning low-energy Coulomb excitation experiments, the [[Rachel,_a_GUI_for_Gosia | GUI]] for Gosia can offer much greater speed and automation in the planning process, including predicting the measurable count rate and estimating the expected errors in the planned experiment.
==Notes==
==Notes==
<references/>
<references/>

Latest revision as of 13:39, 9 May 2011

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