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     Calculations of Synchrotron Radiation in the CesrTA Lattices
                         J.A.Crittenden 
                           26 May 2010
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A compendium of results from the BMAD utility SYNRAD has been collected here:
 http://www.lepp.cornell.edu/~critten/cesrta/ecloud/synrad

The subdirectories are named for the lattice, for example "chess_20090225". 

Further subdirectories are named for the beam particle in the calculation.

Example 1
---------
If one wished to know the synchrotron radiation information
at the position of the central shielded button at SP15W2(s=100.7 m) on the
outside wall of the vacuum chamber for a positron beam for the CHESS lattice, 
one would look in

http://www.lepp.cornell.edu/~critten/cesrta/ecloud/synrad/chess_20090225/positrons/synrad_positive_x_side.txt

for the line

 10156   100.7080    0.0100  4.500E-02  1.573E+02  2.3210E-01  1.5733E+00  5.6966E+15     4.647    32.911     1.183  DRIFT        0.0000E+00             D069#2 SBEND                    B15W    97.9204     1

According to the column headings at the beginning of the file, this
1-cm-long segment has a photon rate of 5.6966E+15. The last column
specifies that a single 1-cm segment upstream contributes to the
rate in this segment at s=100.708. That contributing segment is
in the SBEND B15W at s=97.9204.

The calculation is done for a beam current of 100 mA.
This corresponds to a beam particle rate of 0.1 [C/s] / 1.6e-19 [C/e] = 6.25e17.
So the number of photons per m per beam particle is
5.6966e15 [photons/s] / 0.01 [m] / 6.25e17 = 0.9115 photons/m/s. 

Example 2
---------
How much higher must the bunch population be for an electron beam
in the 2.1 GeV CesrTA lattice to get the same direct synchrotron photon
rate at the central shielded pickup SP15E2 (s=668.3) for an electron beam in the CHESS 5.3 GeV lattice?

Look in 
http://www.lepp.cornell.edu/~critten/cesrta/ecloud/synrad/cta_2085mev_20081107/electrons/synrad_positive_x_side.txt
to find
66946   668.3007    0.0100  4.500E-02  4.807E+00  3.1297E-03  4.8070E-02  2.8410E+15     3.368    32.716     1.071  DRIFT        0.0000E+00               D375 SBEND                    B15E   670.7732     1
 and
http://www.lepp.cornell.edu/~critten/cesrta/ecloud/synrad/chess_20090225/electrons/synrad_positive_x_side.txt
to find
66946   668.3007    0.0100  4.500E-02  2.130E+02  3.4356E-01  2.1296E+00  7.7106E+15     4.283    38.037     1.197  DRIFT        0.0000E+00             D381#2 SBEND                    B15E   670.8392     1
  
The answer is 7.7106E+15 / 2.8410E+15 = 2.714.