HOME ESR EXPERIMENTS LABS etc
E121 E127 E132 E125 E143 laser_cooling_2021 E142 Ê128 E146 E0052 E0018 E0028 E0038
  proton-capture on 118Te  Not logged in ELOG logo
Message ID: 18     Entry time: Tue Jul 23 10:46:29 2019
Author: Laszlo 
Category: Analysis 
Subject: 124Xe pg peak fit using mixed cascade simulation 
Year:  
This entry is the continuation of the cascade effects on the pg peak shape entry:

https://exp-astro.physik.uni-frankfurt.de:8080/E108/475

The main point is that having more cascade makes the impulse carried by one photon smaller --> recoil cone is
smaller --> pg peak gets more centered

When one wants to make an "all-inklusive" simulation the problem comes, that there are too many populated states
after CN* decay (many are just theoretical), also many cascades afterwards as well.
Instead, one can make a "statistical approach":
 1, take an average 1st populated state after the gamma emission of the CN*.
 2, take an average of the gamma energies after the p-capture. (it includes also the photons from the CM* to the
1st state after g emission with energy of [(E_CM - Q) - E_1st_state] --> should these be excluded from the avg.
gamma energy calculation?)
 3, the excited compound nucleus first decays to 1, then cascading down with the avg energy of 2,

    number_of_cascades = E_1st_state/E_avg_gamma. 

    For the 124Xe at 7AMeV using the TALYS code the above values are:
    E_1st_state = 6.74 MeV
    E_avg_gamma = 2.75 MeV
    number_of_cascades = 2.45

To reproduce the resulting avg. pg peak, I took a 2 and a 3 cascade simulations produced by MOCADI and mixed
them as 55% of the 2-cascade and 45% of the 3-cascade for this naiv, statistical model.
Then, to test the peakshape, I fit this mixed distribution to a part our measurement data at 7AMeV after a
sloppy Rutherford background removal (the background removal can be more improved, I used this as a quick method
for now). The calculated Chi^2/NDF ~ 3, which is not a super good value, but taking into account that this is a
strongly naiv model, and the background removal can be also improved, the chi^2/NDF value can be also
interpreted as promising.
Attachment 1: measurement_7AMeV_1.png  37 kB  Uploaded Tue Jul 23 13:27:50 2019  | Hide | Hide all | Show all
measurement_7AMeV_1.png
Attachment 2: sim_7AMeV_1.png  33 kB  Uploaded Tue Jul 23 13:27:55 2019  | Hide | Hide all | Show all
sim_7AMeV_1.png
Attachment 3: pg_peak_fitter_simplex1.root  5 kB  Uploaded Tue Jul 23 13:28:00 2019
Attachment 4: 1st_popul_state.png  36 kB  Uploaded Wed Jul 24 13:16:06 2019  | Hide | Hide all | Show all
1st_popul_state.png
Attachment 5: gamma_distr.png  28 kB  Uploaded Wed Jul 24 13:16:13 2019  | Hide | Hide all | Show all
gamma_distr.png
Attachment 6: output_124Xe_outpopulation_7AMeV  117 kB  Uploaded Wed Jul 24 13:17:13 2019  | Show | Hide all | Show all
Attachment 7: output_124Xe_outspectra_7AMeV  50 kB  Uploaded Wed Jul 24 13:17:26 2019  | Show | Hide all | Show all
ELOG V3.1.5-fc6679b