Re: Low energy muons - how to limit their step length

Help: Forums, postings and threads

Forums, postings and threads

Click on the Forum title, e.g. on the "Forums by Category" page, to read a sequence of postings to the Forum and its threads all in one page. If you are only interested in one thread or the thread following a specific posting, click the thread or the posting, which takes you to a smaller page, which contains only the part you are interested in and may be easier to navigate.

Layout of the posting thread(s)

The posting threads can be shown with/without the text of the postings ("Inline depth"). In addition the depth of the thread can be controlled ("Outline depth"). For both cases several values are provided, which can be toggled. Note that the displayed values are those, which can be chosen, they do not correspond to the actual display status of the thread(s).

Add message

Add a new posting thread to this Forum

Show subscribers

Click "Show subscribers" to get the List of all subscribers, who receive e-mail from postings to this Forum, if they have not explictly unsubscribed from a posting thread. This includes:

Subscribers to the forum
Explicit subscribers to the posting or any of its ancestors
The author of the posting (if he has not unsubscribed)
The authors of any ancestor posting (if they have not unsubscribed)

Some browsers display old pages from the cache

Some browsers (e.g. Firefox) display a page from the cache even though the page has been updated. As a result, one may not get the latest messages in the forum's outline or the logon ID of the previous session appears on the upper right corner. If one suspects that he or she does not get the latest content of a page, try clearing up the personal data from the browser's cache as the following:

Tools -> Clear Private Data -> Clear Private Data (from browser Firefox)

Tools -> Delete Private Data (from browser Opera)

then reflesh the current page to get the latest content.

Details on "Inline depth" and "Outline depth"

Threads and the follow-up messages are numbered. There is one line per posting, normally starting with the posting number. The URLs of a posting and its responses reflect the depth of the follow-up postings. Watch the URLs to see how this is done. Depending on the chosen display options, the thread-display may be incomplete; the number of messages at the next level is, however, displayed, e.g. "…3 message(s)". You may not see all contributors unless you choose "All".

Messages are "chained" if there are only replies at the first level, i.e. 1/1.html, 1/1/1.html etc. In case of "chained" messages the message number is replaced by the icon and there is no indentation.

Inline: Display the subject line only or also the text of the posting(s); for the choice "All" the "Outline" choices are switched off.

Argument Default value Alternative Comment

1 0 1 no text / full text of posting

2 1 All text for level 1 only / text for All postings

Argument	Default value	Alternative		Comment
1	0	1		no text / full text of posting
2	1	All		text for level 1 only / text for All postings

Outline: Choose the depth of the posting thread, successive toggle controls provide increasing detail.

Argument Default value Alternative Comment

1 2 1 2 levels / 1 level (original posting)

2 3 2 3 levels / 2 levels

3 3 All 3 levels / all levels (all postings)

Argument	Default value	Alternative	Comment
1	2	1	2 levels / 1 level (original posting)
2	3	2	3 levels / 2 levels
3	3	All	3 levels / all levels (all postings)

Dear Michel, Vladimir and Peter,

thanks a lot for all your suggestions and advices to my muon-range
problem.

The difference in the range plotted by Michel and by me is due to
the introduction of the momentum smearing of the initial muons.  While
you, Michel, use monoenergetic beam of 28 MeV/c, I used muons with
the Gaussian momentum spread of +/- 3MeV (=sigma).

When I simulate the monoenergetic beam of 28 MeV/c as you did, I do
get a similar picture as you:
http://www-hep2.fzu.cz/~ksedlak/penetrationDepthInCuPlate_monoenergeticII.png
(even though there is some difference in the RMS).

One can see that even in this monoenergetic case, there is a difference
between the case when I limit the step length of the muons to 0.01 mm, or 
imply no limit at all.

I also attach once again the plot with the muon beam with the Gaussian
momentum spred of sigma=3MeV/c, this time including also a smooth profile
for the case when the step length is limited to 0.01 mm:
http://www-hep2.fzu.cz/~ksedlak/penetrationDepthInCuPlate_comparison.png
http://www-hep2.fzu.cz/~ksedlak/incoming_muon_momentum.png 

The following processes are switched on in my simulation:
G4MultipleScattering, G4MuIonisation, G4MuBremsstrahlung, G4MuPairProduction,
and G4StepLimiter,
however the penetration depth looks strange (is not smooth) also when only
the G4MuIonisation is switched on and all other processes are off.
The muons pass only through the G4_Galactic material before they enter 
the sample, and there are therefore no energy losses in front of the sample.
I checked that the muon momentum just in front of the sample is identical 
to the initial muon momentum when they are generated.

Best regards,
Kamil


PS for Michel: I tried to run your test example, but even though the job
   seemed to finish OK, no histograms were plotted, and no file was stored
   in the directory where I run the jobs (TestEm11).  Perhaps because I do
   not have any "AIDA" installed on my computer?