Difference between revisions of "Tagger Hall"
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| − | [ | + | [[Media:08-033-1.pdf | Shielding Basis for Hall D Complex (old note before shielding optimization) ]] |
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| + | [[Media:tag_bg_neut.pdf | Neutron background estimates in the hall ]] | ||
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| + | ==Radius of the exit electron beam pipe== | ||
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| + | 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? | ||
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| + | * 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 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. | ||
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| + | The energy dumped by the radiated electrons into the hall is | ||
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| + | 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> | ||
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| + | 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> | ||
| + | <tr> | ||
| + | <th> r, cm </th> | ||
| + | <th> W/(W<sub>B</sub>·R) </th> | ||
| + | </tr> | ||
| + | <tr> <td> 1 </td> <td> 5.0 </td> </tr> | ||
| + | <tr> <td> 2 </td> <td> 4.3 </td> </tr> | ||
| + | <tr> <td> 3 </td> <td> 3.9 </td> </tr> | ||
| + | <tr> <td> 4 </td> <td> 3.6 </td> </tr> | ||
| + | <tr> <td> 5 </td> <td> 3.4 </td> </tr> | ||
| + | <tr> <td> 6 </td> <td> 3.2 </td> </tr> | ||
| + | <tr> <td> 10 </td> <td> 2.7 </td> </tr> | ||
| + | </table> | ||
| + | |||
| + | 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%. | ||
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%.
