Difference between revisions of "Tagger Hall"
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==Radius of the exit electron beam pipe== | ==Radius of the exit electron beam pipe== | ||
| − | Do we need a wider beam pipe transporting electrons into the dump? | + | Do we need a wider beam pipe transporting electrons into the beam dump? |
| − | By Sept 2014 a 6 | + | By Sept 2014 a 6 inch diameter pipe transports the beam to a place about 2m upstream of the first wall of the beam dump. The pipe 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 during 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 | + | * The deflection of the electron beam from the photon beam in that 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 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 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 | + | The energy dumped by the radiated electrons into the hall is |
| − | W=W<sub>B</sub>/E<sub>o</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 | + | W=W<sub>B</sub>/E<sub>o</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 integration 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) | 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) | ||
Latest revision as of 18:20, 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 beam dump? By Sept 2014 a 6 inch diameter pipe transports the beam to a place about 2m upstream of the first wall of the beam dump. The pipe 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 during 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 that 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 radiated electrons into the hall is
W=WB/Eo·R·∫dk·(Eo−k)/k, where Eo and k are the energies of the incoming electron and of the outcoming photon. The integration 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%.
