Rachel simulated yield output

''This page uses the output of Rachel version 2.0.8 beta.''

The output to the terminal from a "simulated yields" calculation has the following format:

<pre>
Experiment  1  Detector  2
                                       Raw                    Count   Gamma  **Est. intr.  "Corrected"                
Band       Spin    Band    Spin    *Counts        Error    Rate(Hz)  E(keV)    effic.(1)    ***Counts        Error    
----------------------------------------------------------------------------------------------------------------
    gsb    18.0     gsb    16.0        864           29  0.002001    686.0        0.271         3266          198
    gsb    16.0     gsb    14.0      21056          145  0.048741    658.7        0.277        78074         3941
    gsb    14.0     gsb    12.0     400895          633  0.927999    626.6        0.284      1360201        68044
    gsb    12.0     gsb    10.0    5914064         2432 13.689963    579.7        0.296     21145020      1057287
    gsb    10.0     gsb     8.0   65755367         8109 152.21149    512.4        0.315    211214415     10560753
    gsb     8.0     gsb     6.0  527950313        22977 1222.1072    426.3        0.343   1470121661     73506111
    gsb     6.0     gsb     4.0 2866371774        53539 6635.1198    325.6        0.379   7435917854    371795919
    gsb     4.0     gsb     2.0 8174712130        90414 18922.944    213.5        0.382  21045773464   1052288699
    gsb     2.0     gsb     0.0  706191594        26574 1634.7027     93.3        0.078   8631491935    431574719
</pre>


* The "Corrected Counts" column gives the true particle-gamma count emitted into the solid angles of the particle and Ge detectors.  This is equivalent to the total counts for the beam run if the detectors were blackbodies (had 100% efficiency), or if the raw counts were corrected for the absolute p-gamma efficiency. 
* The "Raw Counts" column is only used in this output and is not passed to Gosia.  The raw counts are the estimated p-gamma counts in the raw data, assuming an approximate absolute ''intrinsic'' efficiency for Gammasphere.  
* The "Est. intr. effic." column gives the ''assumed'' absolute ''intrinsic'' efficiency <math>(\epsilon_{intr})</math> of the Ge detector used to calculate the value in the "Raw counts" column.  For example, at 1333 keV, Gammasphere typically has an absolute efficiency of 9% for 100 installed detectors.  Since the solid angle coverage of these 100 detectors is ~6.1 sr, the ''intrinsic'' efficiency is approximately <math>9% * 4\pi / 6.1 = 18.5%</math>.

===Accuracy checking===

The predicted absolute counts (cross sections) for p-<math>\gamma</math> events were checked against perturbation calculations for weakly-coupled two-state systems where the perturbation method is valid.  Both the total count rates and solid angle factors have been re-checked in version 2.0.8.beta and agree with the perturbation calculations where they are applicable.

The ''intrinsic'' efficiency has been estimated more accurately in version 2.0.8.beta.  This will make a noticeable change in the "Raw counts" column.  

===Estimating count rates in a planned experiment===

Since the "Corrected counts" column gives the absolute emitted particle-gamma counts into the particle- and gamma-detector solid angles (for 100% efficiency), these values can be combined with better known values of the particle and gamma efficiencies to predict more accurate "raw" count rates, if the approximate predicted raw counts are not accurate enough.

===Simulated data passed to Gosia===

Note that the "Corrected Counts" are not sent to Gosia as they appear in the table.  

Before the corrected counts are sent to Gosia they are divided by the solid angle of each Ge detector to match Gosia's calculation of yield per unit solid angle.  (This is true in Rachel versions >= 2.0.7.beta; in earlier versions this solid angle factor was neglected.)  All yields sent to Gosia are then multiplied by <math>4\pi</math> so that weak transitions have counts >=1.  This overall multiplicative constant of <math>4\pi</math> has no effect on fitting.  Refer to the page [[Normalization_of_yield_data | Normalization of yield data]] for more detail.