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Dipole and transcient B field effect [message #8597] Tue, 19 May 2009 17:50 Go to next message
Tsitohaina Randriamalala is currently offline  Tsitohaina Randriamalala
Messages: 14
Registered: October 2007
Location: FZ Jülich
occasional visitor
From: *ikp.kfa-juelich.de
Dear all,

I have performed simulations just to check if the B fields (especially for the dipole and the transition region ) are as well implemented in pandaroot as how they are described in the Magnet Technical Design Report (MTDR).
5000 events with single antiproton propagated from the IP at different momenta (1.5 , 4.06 , 8.9 , 11.91 , 15 GeV/c) were run. At z=10m is placed an active plane. No subdetector, including the beam pipe was used.
The projection on x-axis of the hit positions are plotted (see attached files) for these values of momenta.
According to the MTDR, at z=10m, the distance that separates the two extreme antiproton beams trajectories is 0.4mm. Here I got about 1 cm wide. Too wide!!!
I think the field maps need to be treated with more accuracy!
Otherwise the scattered particles by the beam pipe will create a high level of background for some forward subdetectors ( for the luminosity monitor, for instance).

Thank you.
Cheers,


Tsito
Re: Dipole and transcient B field effect [message #8598 is a reply to message #8597] Tue, 19 May 2009 18:49 Go to previous messageGo to next message
StefanoSpataro is currently offline  StefanoSpataro
Messages: 2736
Registered: June 2005
Location: Torino
first-grade participant

From: *to.infn.it
Have you also changed the BeamMomentum in fRun?
Re: Dipole and transcient B field effect [message #8604 is a reply to message #8598] Wed, 20 May 2009 12:34 Go to previous messageGo to next message
Tsitohaina Randriamalala is currently offline  Tsitohaina Randriamalala
Messages: 14
Registered: October 2007
Location: FZ Jülich
occasional visitor
From: *ikp.kfa-juelich.de
Hi,

I add fRun->SetBeamMom(BeamMomentum) in my macro. So if so I did!


Tsito
Re: Dipole and transcient B field effect [message #8609 is a reply to message #8604] Wed, 20 May 2009 16:24 Go to previous messageGo to next message
Tsitohaina Randriamalala is currently offline  Tsitohaina Randriamalala
Messages: 14
Registered: October 2007
Location: FZ Jülich
occasional visitor
From: *ikp.kfa-juelich.de
I plotted here the field components variation along z-axis.

The shifts at the low values of x, at the momenta 4.6 GeV/c and 11.91GeV/c of the antiproton beam in the histogram (in the first mail), may be related to the existing cut at z ~ 600 cm of the y component of B.

And similarly the presence of a jump on By at z~600cm may be the cause of the shift at the high values of x for the case of 8.9 GeV/c beam momentum.


Tsito
Re: Dipole and transcient B field effect [message #9216 is a reply to message #8609] Tue, 18 August 2009 14:53 Go to previous messageGo to next message
Jost Lühning is currently offline  Jost Lühning
Messages: 4
Registered: March 2006
occasional visitor
From: *gsi.de
Has the problem been solved meanwhile?

In the plots the maximum of the magnetic field in the dipole should be about 0.27 T for 4.06 GeV/c, 0.6 T for 4.06 GeV/c, 0.8 T for 11.91 GeV/c, and 1.0 T for 15 GeV/c.
Re: Dipole and transcient B field effect [message #9335 is a reply to message #9216] Sat, 05 September 2009 01:15 Go to previous messageGo to next message
Mohammad Al-Turany is currently offline  Mohammad Al-Turany
Messages: 518
Registered: April 2004
Location: GSI, Germany
first-grade participant
From: *dip.t-dialin.net
Hallo,

Sorry for the delay in solving this trivial problem! any way it is now solved please check and let me know.

regards

Mohammad
Re: Dipole and transcient B field effect [message #9336 is a reply to message #9335] Sat, 05 September 2009 01:31 Go to previous message
Mohammad Al-Turany is currently offline  Mohammad Al-Turany
Messages: 518
Registered: April 2004
Location: GSI, Germany
first-grade participant
From: *dip.t-dialin.net
Hallo,

The corrected maps are also now in the stable branch of pandaroot (-r 6422)

regards

Mohammad
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