Skip to Content.
Sympa Menu

opal - [Opal] Inquiries regarding the sigma matrix of GaussMatched distribution

opal AT lists.psi.ch

Subject: The OPAL Discussion Forum

List archive

[Opal] Inquiries regarding the sigma matrix of GaussMatched distribution


Chronological Thread 
  • From: Huiwen Koay <koay AT rcnp.osaka-u.ac.jp>
  • To: opal <opal AT lists.psi.ch>
  • Subject: [Opal] Inquiries regarding the sigma matrix of GaussMatched distribution
  • Date: Wed, 4 Sep 2019 18:40:53 +0900

Hi.
I have a question regarding the sigma-matrix shown in the output file of OPAL-cycl execution.
In the manual, it is stated that the sigma-matrix computation is based on (x,x′,y,y′,z,δ) instead of (x,px,y,py,z,pz). However, when I try to convert the x' to the sigmapx as shown in the output of MatchedGauss distribution, I couldnt reproduce the same value. 

For example, the output of OPAL shows:
OPAL> * I= 2.2 (mA)  E= 580 (MeV)
OPAL> * EX= 1e-06* EY= 1e-06* ET= 1e-06* FMAPFN ring590_bfld.dat
OPAL> * FMSYM= 8* HN= 6* PHIINIT= 0
OPAL> * ----------------------------------------------------
OPAL> * Converged (Ex, Ey, Ez) = (0.313794, 0.313794, 0.313794) pi mm mrad for E= 580 (MeV)
OPAL> * Sigma-Matrix
OPAL>       3.914 &     -0.6486 &           0 &           0 &      0.4542 &       1.362 \\
OPAL>     -0.6486 &      0.6396 &           0 &           0 &      0.7265 &     -0.2685 \\
OPAL>           0 &           0 &       6.239 &       1.198 &           0 &           0 \\
OPAL>           0 &           0 &       1.198 &      0.3859 &           0 &           0 \\
OPAL>      0.4542 &      0.7265 &           0 &           0 &       2.363 &      0.1752 \\
OPAL>       1.362 &     -0.2685 &           0 &           0 &      0.1752 &      0.8944 \\

OPAL> * ************* D I S T R I B U T I O N ********************************************
OPAL> *
OPAL> * Distribution type: MATCHEDGAUSS
OPAL> * SIGMAX   = 0.001978 [m]
OPAL> * SIGMAY   = 0.002498 [m]
OPAL> * SIGMAZ   = 0.001537 [m]
OPAL> * SIGMAPX  = 4.129e-05 [Beta Gamma]
OPAL> * SIGMAPY  = 3.639e-05 [Beta Gamma]
OPAL> * SIGMAPZ  = 4.49e-05 [Beta Gamma]
OPAL> * AVRGPZ   = 0 [Beta Gamma]
OPAL> * CORRX    = -0.4099
OPAL> * CORRY    = 0.7722
OPAL> * CORRZ    = 0.1205
OPAL> * R61      = 0.7277
OPAL> * R62      = -0.355
OPAL> * R51      = 0.1493
OPAL> * R52      = 0.5909
OPAL> * CUTOFFX  = 3 [units of SIGMAX]
OPAL> * CUTOFFY  = 3 [units of SIGMAY]
OPAL> * CUTOFFZ  = 3 [units of SIGMAZ]
OPAL> * CUTOFFPX = 3 [units of SIGMAPX]
OPAL> * CUTOFFPY = 3 [units of SIGMAPY]
OPAL> * CUTOFFPZ = 3 [units of SIGMAPY]
As the definition of rms-emittance is given by emittance=sqrt(sigma_11*sigma_22-sigma12*sigma21). However, if I used only the red coloured matrix, I can neither reproduce the matched emittance at 0.3137 pi mm mrad, nor the rms-px by taking sqrt(639)/1000*betagamma. I can only obtain the rms of X by taking the sqrt of 3.914.
I would appreciate if somebody could help and shed a light on this matter.
Thanks again.

Best regards,
Huiwen



Archive powered by MHonArc 2.6.19.

Top of Page