1 / 34

Radiation shielding studies for MTA

Radiation shielding studies for MTA. Igor Rakhno October 30, 2008. Starting approximately in spring 2007, the following shielding issues were studied:. Accident on a quad ~17 m upstream of the concrete block Accidents around the 12-ft concrete block (and re-routing)

cais
Download Presentation

Radiation shielding studies for MTA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Radiation shielding studies for MTA Igor Rakhno October 30, 2008

  2. Starting approximately in spring 2007, the following shielding issues were studied: • Accident on a quad ~17 m upstream of the concrete block • Accidents around the 12-ft concrete block (and re-routing) • Accident on the 2nd beam stop upstream the MTA wall • Vertical penetration (vent) at the upstream corner of MTA hall • (re-routing) • Shielding block in the access pit • Thickness of the shielding above the MTA roof • Horizontal cryo penetrations in the MTA hall • There was a lot of minor requests from radiation safety group (Mike Gerardi et al.)

  3. Plan view of the Linac – MTA area

  4. Plan view – MTA

  5. Accidents around the 12-ft concrete block (and re-routing)

  6. Plan view @ beam line elevation

  7. Calculated dose in the penetrations @ X=370 cm LocationDose (mrem/pulse) Beam pipe 5 m US the 12-ft sh.block 1 Beam pipe 2.5m US the 12-ft sh.block 1 Beam stop itself 1 Beam pipe inside the 12-ft sh.block 25 Quad 5 m DS the 12-ft sh.block 240 Quad 1' DS the 12-ft sh.block 500

  8. Re-routing and re-stacking (Pushka’s model)

  9. The expected dose rate above the 12-ft shielding block due to the accident is estimated to be less than 1 mrem/pulse.1 pulse = 1.6×1013 protons FRCM (Accident) Maximum dose equivalent Controls expected in 1 hour _________________________________________________________ D < 1 mrem No precautions 1 < D < 5 mrem Signs ‘Controlled Area’. No occupancy limits.

  10. Accident on the 2nd beam stop upstream the MTA wall (with MTA RF trench extension)

  11. Geometry model – cross section

  12. Geometry model – cross section

  13. Plan view (red dots – hypothetical beam loss locations)

  14. Star density distribution – plan view

  15. Dose equivalent – cross section

  16. The expected dose rate above the shielding is estimated to be less than 1 mrem/pulse.1 pulse = 1.6×1013 protons FRCM (Accident) Maximum dose equivalent Controls expected in 1 hour _________________________________________________________ D < 1 mrem No precautions 1 < D < 5 mrem Signs ‘Controlled Area’. No occupancy limits.

  17. Vertical vent in MTA hall, 20" (elevation view)

  18. Target – 1-cm copper (10% of interaction length) – re-routing?

  19. Accident on the 2nd beam stop

  20. Shielding block in the access pit (cross section)

  21. Thickness of the shielding above the MTA roof (recent request from Alan Bross, 1-cm Cu target @ 15 Hz)

  22. Horizontal cryo penetrations in the MTA hall

  23. Realistic model

  24. Realistic model

  25. Calculated dose attenuation curve for the 12" penetration(dose averaged in vacuum cells)

  26. The existing Linac safety envelope is 3.5×1017 p/hr which means rep. rate approximately 6.1 Hz at 1.6×1013 ppp. • D0 = 2.2×106 mrem/hr for 10% of I.L. @ 1 Hz. • D0 * 10-8 * 10 * 6.1 = 1.3 mrem/hr = 6.1×10-5mrem/pulse.

More Related