Integrated yields

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(still in progress)
(separated p-gamma event calculation into a new subsection)
 
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After an integration, the cross section in mb is obtained by multiplying the yield by
After an integration, the cross section in mb is obtained by multiplying the yield by
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the Ge solid angle in <math>sr</math> and dividing by the target thickness in <math>mg/cm^2</math>.  You can also calculate the absolute
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the Ge solid angle in <math>sr</math> and dividing by the target thickness in <math>mg/cm^2</math>.   
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p-gamma counts expected using the equation following equation 6.44b in the manual:
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Detected p-gamma coincident events  
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===Detected p-gamma coincident events===
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The absolute p-gamma counts expected can be calculated using the equation following equation 6.44b in the manual:
<math>N_i = 10^{-30} [Q / qe] [N_A / A] Y(I_i-->I_f) \epsilon_p \epsilon_\gamma \Delta \Omega_\gamma</math>, (1)
<math>N_i = 10^{-30} [Q / qe] [N_A / A] Y(I_i-->I_f) \epsilon_p \epsilon_\gamma \Delta \Omega_\gamma</math>, (1)
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where <math>Q</math> is the integrated beam current incident on the target during the experiment, <math>q</math> is the average charge state of the beam, <math>e</math> is the electron charge,  
where <math>Q</math> is the integrated beam current incident on the target during the experiment, <math>q</math> is the average charge state of the beam, <math>e</math> is the electron charge,  
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If the absolute efficiency is known well, then it is possible to retrieve
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If the absolute efficiency is known well, then it is possible to reproduce
the actual counts measured in the photopeak by putting the efficiency into this
the actual counts measured in the photopeak by putting the efficiency into this
equation.
equation.
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Refer to the page on the [[particle_singles | particle singles]], which is a cross section given in the same output with the integrated yields.
Refer to the page on the [[particle_singles | particle singles]], which is a cross section given in the same output with the integrated yields.
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==Representing a <math>4\pi</math> Array in Gosia==
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A <math>4\pi</math> array can be represented in Gosia in a single calculation without summing the output of a large number of detectors.  See the page on [[four_pi_arrays | 4pi arrays]].
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==Quickly representing a summed 4pi array==
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Gosia can quickly integrate the p-<math>\gamma</math> events over a <math>4\pi</math> Ge array without adding a detector at every laboratory position.  In order to do this, the output file 9 can be modified to make the first two attenuation coefficients 0 for all orders.  (File 9 is the output of OP,GDET, commonly called the *.gdt file.  For Gammasphere the *.gdt file would look something like
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<pre>
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  1
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  25.0
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  5.000E-02
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0.  0.  0.9951
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0.  0.  0.9854
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0.  0.  0.9711
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0.  0.  0.9521
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0.  0.  0.9379
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0.  0.  0.9013
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0.  0.  0.8699
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0.  0.  0.8349
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</pre>
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where the first two columns have been set to 0. to simulate a 4pi array.  In this case the <math>\epsilon_\gamma</math> value would
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still be the absolute photopeak efficiency, but <math>\Delta\Omega_\gamma</math> would be 4*pi.
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See the manual entries on OP,GDET and "Gamma Detector Solid Angle Attenuation Factors" for more information on these attenuation coefficients.
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Latest revision as of 13:40, 15 June 2011

Retrieved from "https://www-user.pas.rochester.edu/~gosia/mediawiki/index.php/Integrated_yields"
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