Difference between revisions of "Tagger Hall"
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* The full power of the photons is W<sub>B</sub>·R, where W<sub>B</sub> is the power of the electron beam and R is the radiator thickness in R.L. | * The full power of the photons is W<sub>B</sub>·R, where W<sub>B</sub> is the power of the electron beam and R is the radiator thickness in R.L. | ||
| − | The energy dumped by the radiator electrons into the hall is | + | The energy dumped by the radiator electrons into the hall is |
| − | W<sub>B</sub>·R·(ln(L/r)-1+r/L) | + | |
| + | W=W<sub>B</sub>·R·∫dk·(E<sub>o</sub>-k)/k, where E<sub>o</sub> and k are the energies of the incoming electron and of the outcoming photon. The integral limits are E<sub>o</sub>·(r/(L+r)), E<sub>o</sub> | ||
| + | |||
| + | W=W<sub>B</sub>·R·(ln((L+r)/r)-1+r/(L+r))≈W<sub>B</sub>·R·(ln(L/r)-1+r/L) | ||
<table> | <table> | ||
<tr> | <tr> | ||
Revision as of 14:27, 16 September 2014
Shielding Basis for Hall D Complex (old note before shielding optimization)
Neutron background estimates in the hall
Radius of the exit electron beam pipe
Do we need a wider beam pipe transporting electrons into the dump? By Sept 2014 a 6 imch diameter pipe brought the beam to about 2m in front of the dump wall. It ends with a thick flange connected to a 1.5 inch pipe transporting the beam through the wall. There is a girder with a valve between the flange and the wall. The flange became a hot spot after the first beam tune in May 2014. Would it help to install a wider pipe from the flange through the wall?
- The deflection of the electron beam from the photon beam in this area is about L=400cm
- The electrons deflected not more than r cm from the trajectory of the non-radiated beam go into the beam dump. The others dump their energy into the hall.
- The full power of the photons is WB·R, where WB is the power of the electron beam and R is the radiator thickness in R.L.
The energy dumped by the radiator electrons into the hall is
W=WB·R·∫dk·(Eo-k)/k, where Eo and k are the energies of the incoming electron and of the outcoming photon. The integral limits are Eo·(r/(L+r)), Eo
W=WB·R·(ln((L+r)/r)-1+r/(L+r))≈WB·R·(ln(L/r)-1+r/L)
| r, cm | W/(WB·R) |
|---|---|
| 1 | 5.0 |
| 2 | 4.3 |
| 3 | 3.9 |
| 4 | 3.6 |
| 5 | 3.4 |
| 6 | 3.2 |
| 10 | 2.7 |
The increase of the exit pipe radius from 2cm to 4cm would reduce the power dumped in the hall by the radiated electrons by about 15%.
