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S1287

Fields marked with * are required Entry time: Thu Nov 14 20:39:11 2024 Author*: Type: - please select - Routine Other Category: - please select - General Other Subject: <p> <table width="98%" align="center" cellspacing="1" style="border:1px solid #486090;"> <tbody> <tr> <td cellpadding="3px" style="background-color:#486090; font-weidht:bold; color:white;">Jessica Tomlinson wrote:</td></tr> <tr> <td cellpadding="10px" style="background-color:#FFFFB0;"><p>&nbsp;<u>Energy vs Time plots<br /> </u></p> <p style="margin-bottom: 0cm; ">I updated the monte carlo written by Alex to include time and also created new SRIM tables for 250 Torr rather than 300 Torr. I ran the Monte Carlo for a beam energy of 4.44MeV/u and plotted energy vs time for each detector. It should be noted that there are 2 codes, one for scattering 21Ne(p,p)and one for the reaction 21Ne(p,a) and the number of scattered particles as opposed to the number of reaction products from (p,a) are not what is expected in the data but the energies and timing are.</p> <p style="margin-bottom: 0cm; ">Attachment 1 shows energy vs time in S2-1 (downstream-heavy ion detector) from the data runs at 4.44Mev/u. Beam pulses are 85ns apart. The cuts on this include: equal energy cuts between the front and back of each detector removing interstrip hits, coincidence hits between S2-1 and S2-2, must be a hit in the front and back of each detector, phi cut so that particles must hit S2-1 and S2-2 at 180 degrees to one another. A feature not shown in the monte carlo is the second weaker line of particles, hitting the detector just after the first stronger line. I am not sure what this is, could be beam scattering off the entrance window or from N gas left over in the chamber?</p> <p style="margin-bottom: 0cm; ">Attachment 2 shows the same plot (energy vs time) simulated with the monte carlo for scattering reactions and for the (p,a) reaction. This shows that the reaction is dominated by beam scattering from the target H2 gas. The 18F extends to lower energies as shown in the monte carlo and there are some lower energy points in the data &nbsp;(Att 1) which could correspond to this, however I am not sure whether this is F or beam scattering from the entrance window which also produces an extended range of energies.&nbsp;</p> <p style="margin-bottom: 0cm; ">Attachment 3 shows energy vs time data plot in S2-2(upstream - light ion detection), at same energy and with same cuts as for s2-1 in Att 1. Again comparing this to attachment 4 which shows the Monte Carlo calculated energy vs time plot for S2-2 the data is dominated by scattering events. The small number of events which happen after 8.5 Mev (protons will punch through the detector after this) could be alphas. The Monte Carlo shows the alpha particles have a wider energy range than the protons.&nbsp;</p> <p style="margin-bottom: 0cm; "><u>Other plots</u></p> <p style="margin-bottom: 0cm; ">I ran a 'gas out' data set to see how much scattering was coming from the entrance window to the chamber. There is no gas out run for 4.44 MeV/u so I used the one at 4.11MeV/u. This shows that there was some scattering from the window getting through the cuts described above, in S2-2 they go no higher than 8 MeV which makes me think it is scattering with protons because of the punch through energy. To check it was from the window I checked a run where there was no target and no window in the chamber and saw nothing after the cuts above.&nbsp;</p> <p style="margin-bottom: 0cm; ">Other plots I am looking at include: time(S2-1) vs time (S2-2), energy(S2-1) vs energy(S2-2), energy vs strip for each detector, time of flight difference between S2-1 and S2-2 vs energy difference between two detectors, difference in theta (front strip) vs sum energy of two detectors, time of flight vs energy difference.&nbsp;</p> <p style="margin-bottom: 0cm; ">&nbsp;</p> <p style="margin-bottom: 0cm; ">eol</p></td> </tr> </tbody> </table> </p><p> </p> Encoding: HTML   ELCode   plain   Suppress Email notification Attachment 1:

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