stephenbrooks.orgForumMuon1GeneralHow are transfer percentages worked out?
Username: Password:
Search site:
Subscribe to thread via RSS
[OCAU] badger
2003-12-16 19:26:42
In honour of my current position at the top of SolenoidsTo15cm with 9.800777% I did a little looking around at my results.

If you use the commandline version, then you see the number of particles currently being simulated (out of another figure, I guess the total number of particles which have been tracked at one time or another).

Now IIRC the transfer percentage is the proportion of particles which make it out the other end compared to the number created in the tantalum rod.

looking at the command line, one would expect that the higher the number of particles being simulated as we hit 200ns, the higher the transfer, which is generally the case, but not always.

for example, I am currently working a on sim which had 763/62107 particles at 200ns, and this gave a transfer of 9.803672%, and thus went into a queue to be rechecked.  the next sim gave 764/61922, but the transfer was "only" 9.666763%, the 2nd recheck gave 743/62124 for 9.713935%

I am thinking that perhaps only the number of muons in the beam counts towards the transfer, as some of the particles will still be pions, although these should decay to muons in short order.

a previous sim (I just looked back at the last few sims I did) had 1/28389 for 0.018135%, but the one before scored a slightly higher 0.018276% with 0/27391 !

any more info?

www.BadgerMotorsport.tk Proudly sponsored by GRX-Computers
Stephen Brooks
2003-12-17 02:24:30
The "particles at 200ns" figure is not the one to look at, or at least, the smaller number before the slash is just how many low-energy particles are somehow left over floating around in the apparatus.  The second figure (after the slash) is more meaningful: it shows the number of particles there have "ever" been in the simulation.
You'll actually see a big drop in particles retained somewhere around 100-120ns, and that is where the majority of the beam hits the "finish aperture".

HB Pencils, also sold as "Moron's Choice" Graphite Cigars.
[OCAU] badger
2003-12-18 16:53:41
yeah I have noticed there is an increase in the rate loss of particles at ~104ns and then a rapid acceleration in particle loss at ~107ns.

you haven't really answered my question, in my example above the 2nd recheck gave a higher 2nd figure than the initial run, but a lower transfer, so I know there must be more to it...

edit: Well done edco for taking the #1 transfer overnight.

www.BadgerMotorsport.tk Proudly sponsored by GRX-Computers
AySz88
2003-12-18 20:46:35
If you look at the graphical version, you'll see that the entire beam eventually hits a "wall" at the end of the simulation (the 'finish aperture') , and the particles turn green.  These particles have successfully passed through the solenoids, but are no longer are being simulated (they won't count towards "Current#/Total# particles at 200ns").

The "Current#/Total# particles at 200ns" refers to the particles that are still moving around when the simulator reaches 200ns - these haven't reached the end.  It is not unlikely that there were fewer particles floating around at the end of the second recheck, but more particles hit the finish aperature, and thus more particles had exited the solenoids.
Stephen Brooks
2003-12-19 00:49:44
quote:
Originally posted by [OCAU] badger:
you haven't really answered my question, in my example above the 2nd recheck gave a higher 2nd figure than the initial run, but a lower transfer, so I know there must be more to it...
The figure on the screen counts both pions and muons, but the percentage transfer just counts muons.  So they won't be directly proportional to each other or anything like that.  Also particles have varying "weights", which are counted in the percentage but not the raw particle-numbers shown as the simulation progresses.

HB Pencils, also sold as "Moron's Choice" Graphite Cigars.
: contact : - - -
E-mail: sbstrudel characterstephenbrooks.orgTwitter: stephenjbrooksMastodon: strudel charactersjbstrudel charactermstdn.io RSS feed

Site has had 25160225 accesses.