Meeting No4 - Threshold Pi0 beam energy determination

Energy losses:

I had to re-estimate energy losses for all three targets because in previous calculatios I considered Ti target window instead of the Al one. Here are corrected results:

Carbon target:

   Material          |       Thickness [cm]
---------------------------------------------
 Carbon target       |        0.0419
 Aluminium window    |        0.04064       
    Air              |        65.1
 Kapton window       |        0.03556

Tantalum target:

   Material          |       Thickness [cm]
---------------------------------------------
 Tantalum target     |        0.001213
 Aluminium window    |        0.04064          
    Air              |        65.1
 Kapton window       |        0.03556

Hydrogen target:

   Material          |       Thickness [cm]
---------------------------------------------
 Aluminium           |        0.0127
 Hydrogen target     |        6.0
 Aluminium           |        0.0127
 Aluminium window    |        0.04064       
    Air              |        65.1
 Kapton window       |        0.03556

In the end we got following estimations for the energy losses:

  Target       | Energy Loss [MeV]
------------------------------------
   Hydrogen    |     1.64 - 1.68
   Carbon      |     0.43
   Tantalum    |     0.35

DB - files

I have checked which DB are we using. At the moment we are using the DB from the beginning of the Pi0 experiment: 20080402

Spectrometer Constant (pc) and Nilanga's formula

In this analysis we didn't use spectrometer constant from EPICS any more. We have calculated it from magnetic field, using Nilanga's polynomial formula. Following plots show difference between the central momenta from EPICS entries and Nilanga's formula:

Magnetic field:

Central Momentum:

Fitting Results:

Here are our latest fitting results. We have done two types of fits:

1.) we fitted elastic points as a function of the scattering angle at fixed mass.
2.) we fitted elastic points as a function of target mass at fixed scattering angle.

Here are the results:

Angle Fit:

Hydrogen:

  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
-------------------------------------------------------------------------
   1  E0           1.19199e+03   2.08205e-01

  NO.   NAME      VALUE            ERROR       NEGATIVE      POSITIVE
-------------------------------------------------------------------------
  1  E0           1.19222e+03   5.59762e-02

Carbon:

  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
-------------------------------------------------------------------------
   1  E0           1.19315e+03   2.79028e-01

  NO.   NAME      VALUE            ERROR       NEGATIVE      POSITIVE
-------------------------------------------------------------------------
   1  E0           1.19309e+03   1.17873e-01

Tantalum:

  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
-------------------------------------------------------------------------
   1  E0           1.19336e+03   1.60159e-01

Mass Fit:

1st Series:

  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
---------------------------------------------------------------------------
   1  E0           1.19373e+03   1.91058e-01

2nd Series:

  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
---------------------------------------------------------------------------
   1  E0           1.19452e+03   2.60247e-01

3rd Series:

  NO.   NAME      VALUE            ERROR      NEGATIVE      POSITIVE
---------------------------------------------------------------------------
   1  E0           1.19256e+03   3.22166e-01