Shielding and BCS Requirements for LCLS Injector Operation Phase 1

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1 Shielding and BCS Requirements for LCLS Injector Operation Phase 1 Stan Mao, Alyssa Prinz Radiation Protection Department Stanford Linear Accelerator Center

2 Operation modes during the LCLS injector phase-one operation Beam Beam will run from the injector gun to dump SDMP during LINAC operation, which is located in sector Magnets BX01/BX02 will be locked off. Beam will run from the injector gun to dump TD11, which is located in sector Dump TD11 will be disabled in unless the BCS proposal for LCLS downstream of the Dump TD11 is approved by RSC/RSO. IF the BCS proposal is approved, and there are no new radiation sources from Dump TD11 to the LINAC/BSY/ESA, LCLS beam will run beyond Dump TD11 to the LINAC/BSY/ESA.

3 Outline of the Presentation Shielding requirements for penetrations in Sector-20 Alcove Normal operation Maximum credible beam (MCB) Shielding requirements for penetrations above the 2-mile LINAC Sector-21 Normal operation BCS devices for injector phase-i operation Mis-steering Conditions, and Maximum Credible Beam Loss for LCLS Injector gun only Mis-steering Conditions, and Maximum Credible Beam - for CID beam Radiological environmental impact of LCLS injector phase-one operation Radiation commission plan for LCLS injector phase 1 operation Summary

4 Part 1 Shielding requirements for penetrations in Sector-20 Alcove

5 LINAC Penetration Vent Unused Laser penetration Injector Vault

6 LCLS injector vault and beam loss points Wall Stairway 4 1 A B Wall 2 3 D C E E Wall Linac

7 Beam losses in normal operation Beam loss point Dark current parameters Beam parameters A 6.2 MeV, 2.2 W 6.2 MeV, 0.7 W Faraday cup FC01 (source = gun) B 6.2 MeV, 2.2 W 6.2 MeV, 0.7 W YAG02, thick screen (source = gun) C 6.2 MeV, 0.45W 6.2 MeV, 0.7 W Faraday cup FCG1 (source=gun) D 56 MeV, 1.1 W 62 MeV, 7.4 W YAG03, thin screen (source = accelerator sectionl0a) E 130 MeV, 2.5 W 135 MeV, 16 W OTRH1, thin screen (source = sections L0A&L0B)

8 Radiation shielding requirements Beam losses in normal running condition Shielding requirement Dose rate in normal running condition Dose rate from SLED Total dose rate Above Laser Penetration Mainly from point A Beam and dark current Above Unused Penetration Mainly from point C Beam and dark current 7 iron 18 iron 0.52 mrem/hr Gamma 0.40 mrem/hr Gamma 1 ft to the side of Stairway Penetration Mainly from point C Beam and dark current PPS barrier 1 ft away from the edge of the penetration 0.32 mrem/hr Gamma < 0.1 mrem/hr Gamma < 0.1 mrem/hr Gamma < 0.1 mrem/hr Gamma 0.62 mrem/hr 0.50 mrem/hr 0.42 mrem/hr Gamma Gamma Gamma Dose rate limit 1000 mrem/year 1000 mrem/year 1000 mrem/year

9 Shielding for LASER penetration Six Laser transport tubes (OD = 2.5") and one lifting tube (4" x 4")

10 Shielding for LASER penetration

11 Shielding for Un-used penetration

12 Shielding for LASER penetration

13 Shielding for Un-used penetration 18 Steel plug Steel plate Steel Balls, 1/8 (3mm)

14 Shielding for Un-used penetration 18 Steel plug

15 Ventilation

16 Maximum credible beam from Gun 1000 W loss in Point A Laser Penetration Unused Penetration Stairway Penetration (1ft outside) Dose rate 175 mrem/hr 5.4 mrem/hr 21 mrem/hr Radiation type Gamma Gamma Gamma BSOIC Yes, Yes, Gamma sensor Gamma sensor Trip level 10 mrem/hr 10 mrem/hr

17 Maximum credible beam from Gun 200 W loss in Point C Laser Penetration Unused Penetration Stairway Penetration (1ft outside) Dose rate 0.1 mrem/hr 67 mrem/hr 55 mrem/hr Radiation type Gamma Gamma Gamma BSOIC Yes, Gamma sensor Trip level 10 mrem/hr

18 Maximum credible beam from L0B 2200 W loss in Point D Laser Penetration Unused Penetration Stairway Penetration (1 foot outside) Dose rate 27 mrem/hr 7.1 mrem/hr 34 mrem/hr Radiation type Neutron Neutron Neutron BSOIC Yes, Neutron sensor Trip level 10 mrem/hr

19 Two BSOICs are required BSOIC with gamma sensor at the top of Laser penetration, trip at 10 mrem/hr BSOIC with both gamma and neutron sensors on PPS barrier wall around the stairway, trip at 10 mrem/hr

20 Part 2 Shielding requirements for penetrations above the 2-mile LINAC Sector-21

21 Penetrations and nearest main source in the 2-mile LINAC sector-21 Penetration Nearest main source Energy (GeV) Beam loss (W) 21-1 Magnet BX01/ Dump SDMP X-iris (Aperture radius = mm) Dark current 21-4 Collimator CE11 in BC1 chicane Nominal = 0.1 W 21-5 Dump TD

22 Radiation shielding requirements Main Source Penetration Shielding Total dose rate Total dose rate requirements above (mrem/hr) outside (mrem/hr) Magnet BX01/ Borax Dump SDMP Borax X-iris Borax Collimator CE Borax 3.3/30 W 0.73/30 W 16 Borax + 2 lead between TD11 and Pen Dump TD OR 16 Borax + 3 steel between TD11 and Pen

23 Shielding requirements for residual activities Source 3 lead 5 steel (mrem/hr) (mrem/hr) Dump SDMP Dump TD

24 Steel shielding for Dump TD11 Penetration 21-5 Steel shield Dump TD11 Shield for residual activity 6 foot tall person

25 Steel shielding for Dump TD11

26 Part 3 BCS devices for injector phase-i operation

27 BCS devices Two BCS flow switches on the dump SDMP A pair of LIONs (LION 1A and 1B) will limit beam losses to 100 W or less in the BX01/BX02, BXS/SDMP region A pair of LIONs (LION 2A and 2B) will limit beam losses to 100 W or less in the LINAC X-iris, BC1/CE11, and dump TD11 areas

28 LION locations

29 Part 4 Mis-steering Conditions, and Maximum Credible Beam Loss for LCLS Injector gun only

30 maximum credible beam power for LCLS operation Location BX01/02 BXS/SDMP X-iris BC1/CE11 TD11 Beam energy and maximum credible power GeV 5 kw GeV 5 kw GeV 1.5 kw GeV 1.5 kw GeV 1.5 kw

31 The dose rates outside penetration 21-1 Penetration 21-1 Dose rate in normal running conditions Dose rate in missteering conditions Dose rate in maximum credible beam loss GeV GeV GeV 2 W 100 W 5 kw 0.09 mrem/hr 4.5 mrem/hr 0.23 rem/hr The main source is the beam losses in magnets BX01/BX02 region.

32 The dose rates outside penetration 21-2 Penetration 21-2 Dose rate in normal running conditions Dose rate in missteering conditions Dose rate in maximum credible beam loss GeV GeV GeV 16 W 100 W 5 kw 0.24 mrem/hr 1.5 mrem/hr rem/hr The main source is the beam losses in the region of magnet BXS and dump SDMP.

33 The dose rates outside penetration 21-3 Penetration 21-3 Dose rate in normal running conditions Dose rate in missteering conditions Dose rate in maximum credible beam loss GeV GeV GeV 0.5 W 100 W 1.5 kw 0.03 mrem/hr 6 mrem/hr 0.09 rem/hr* *The main source is the beam losses in X-iris region.

34 The dose rates outside penetration 21-4 Penetration 21-4 Dose rate in normal running conditions Dose rate in missteering conditions Dose rate in maximum credible beam loss GeV GeV GeV W 100 W 1.5 kw Nominal = 0.1 W 0.73 mrem/hr/30 W 2.4 mrem/hr rem/hr* *The main source is the beam losses on Collimators CE11 in BC1 chicane.

35 The dose rates outside penetration 21-5 Penetration 21-5 Dose rate in normal running conditions Dose rate in missteering conditions Dose rate in maximum credible beam loss GeV GeV GeV 30 W 100 W 1.5 kw 0.44 mrem/hr 1.5 mrem/hr 0.02 rem/hr* *The main source is the beam losses on dump TD11.

36 Part 5 Mis-steering Conditions, and Maximum Credible Beam Loss for CID beam

37 The Improvements of the shielding and BCS on LINAC penetrations to 21-5 Shielding Prior to borax 16 borax 16 borax 16 borax 16 borax Prior to LCLS injector operation 24 borax 24 borax 16 borax 24 borax 16 borax 3 steel between TD11 and Pen 21-5 BCS: Two pairs of LIONs along oenetrations 21-1 to 21-5 For E158, the CID beam power used to calculate the dose rate in the missteering conditions is 90 kw. It was based on that a mis-steered CID beam might be able to melt an accelerator structure if the power were above 90 kw, thereby shutting down operation of the CID beam.

38 Three new radiation sources during CID beam operation X-iris, the aperture of the X-iris is 3.73 mm radius, smaller than main LINAC aperture (5 mm radius). It need to be removed during high-power CID beam operation. BC1 is a moveable chicane, CE11 is a set of energy collimator jaws in BC1. Chicane BC1 should be in the LINAC line, and be turned off, and Collimator CE11 should be fully open during CID operation. TD11 in an insertable tune-up dump. Dump TD11 should be in out position during CID beam operation.

39 Mis-steering steering Conditions, and Maximum Credible Beam Loss conditions from New sources Failure cases X-iris BC1 chicane Dump TD11 The X-iris has smaller 1) BC1 is on and BC1 1) dump TD11 in aperture than CID out off beam line waveguide 2) CE11 closed CID beam enters into LCLS beam line during LCLS operation LCLS components are mis-set during CID operation 1) Not be taken out Should be taken out during high-power CID operation 1) Not turn BC1 off and BC1 is not at the beamline 2) CE11 closed Not move dump TD11 out off the beam line

40 The dose rates outside penetration 21-3 Penetration 21-3 Dose rate in mis-steering conditions Dose rate in maximum credible beam loss (Not burn through X-iris) 30 GeV 30 GeV 100 W 90 kw 6 mrem/hr 5.4 rem/hr* *Maximum credible beam (30 GeV and 90 kw) is lost in the X-iris, and produce 5.4 rem/hr outside the penetration The maximum power capability of X-iris is 90 kw with water cooling.

41 The dose rates outside penetration 21-4 Penetration 21-4 Dose rate in mis-steering conditions Dose rate in maximum credible beam loss (Not burn through CE11) 30 GeV 30 GeV 100 W 135 kw 2.4 mrem/hr 3.24 rem/hr* *Maximum credible beam (30 GeV and 135 kw) is bent by magnet BC1 and hit collimators CE11. It will produce 3.24 rem/hr outside the penetration The maximum power capability of collimator CE11 is 135 kw with water cooling.

42 The dose rates outside penetration 21-5 Penetration 21-5 Dose rate in mis-steering conditions Dose rate in maximum credible beam loss (Not burn through TD11) 30 GeV 30 GeV 100 W 20 kw 1.5 mrem/hr 0.3 rem/hr* Maximum credible beam (30 GeV and 20 kw) is lost in the dump TD11, and produce 0.3 rem/hr outside the penetration The maximum power capability of dump TD11 is 20 kw with water cooling.

43 Part 6 Radiological environmental impact of LCLS injector phase-one operation

44 Dose to public Analytical calculation shows that the direct radiation dose to the public through skyshine is negligible. Analytical calculation is used to estimate the radiation dose to a member of the public, the Maximally Exposed Individual (MEI), from the release of radioactive air. It shows that the dose to the MEI (located at north Sand Hill road) is about mrem/y due to LCLS injector phase operation, assuming that the beam will park on dump TD11 for 365 days in This MEI dose from LCLS operations is much smaller than the overall MEI dose of 0.04 mrem/y from CY2006 SLAC operations..

45 Main radioactive isotopes produced in soil around SDMP and Dump TD11 SDMP 16 W TD11 30 W PEP-II, IR10 9 W H3 (Bq/g) Be7 (Bq/g) Na22 (Bq/g) Assuming that the beam will park on dump SDMP or dump TD11 for 365 days in 2007

46 Part 7 Radiation commission plan for LCLS injector phase 1 operation

47 Radiation commission plan for LCLS injector operation phase 1 Area Plan Beam rate Radiation Hour Hz SLED Cavities, Measure radiation in LINAC gallery: near SLED cavities, RF hut and 30 Gamma 3 klystrons, 20-5, 20-6, 20-7 and 20-8 laser room with gun off Measure radiation in laser room and around the PPS barrier with 30 Gamma 6 Sector-20 beam parked on FC01, YAG02, and FCG1, and check BSOIC reading Alcove Measure radiation in laser room and around the PPS barrier with YAG03 and YAG04 in the beam 30 Gamma Neutron 6 Sector-21 LINAC penetrations 21-1, 21-2, 21-3, 21-4, 21-5, 21-6 Measure radiation in gallery near penetrations 21-1 and 21-2 with beam parked on 135-MeV spectrometer SDMP, and calibrate LION 1A and LION1B Measure radiation in gallery near penetrations 21-1 and 21-2 with missetting of magnet BXS, and calibrate LION 1A and LION1B Measure radiation in gallery near penetrations 21-1 and 21-2 with missetting of magnet BX01/ 02, and calibrate LION 1A and LION1B Measure radiation in gallery near penetrations 21-3, 21-4, 21-5 and 21-6 with 30-W beam parked on TD11, and calibrate LION 2A and LION2B Measure radiation in gallery near penetrations 21-3, 21-4, 21-5 and 21-6 with Collimator CE11 from close to open in four points, and calibrate LION 2A and LION2B 30 Gamma Neutron 10 Gamma Neutron 10 Gamma Neutron 30 Gamma Neutron 30 Gamma Neutron

48 Summary The total dose rates above the laser penetration, unused penetration, and around the PPS barrier surrounding the stairway are about 0.5 mrem/hr during normal operation. The highest dose rate is 175 mrem/hr for the maximum credible beam loss. Two BSOICs are required to be installed in the Sector 20 alcove, and set to trip at 10 mrem/hr. For LCLS injector beam only - the dose rates outside the penetrations 21-1, 21-2, 21-3, 21-4 and 21-5 are less than 0.5 mrem/hr, 6 mrem/hr, and 0.23 rem/hr for normal, mis-steering, and maximum credible beam losses, respectively. For CID beam - the dose rates outside the penetrations 21-1, 21-2, 21-3, 21-4 and 21-5 from new sources (collimator CE11 and dump TD11) are less than 6 mrem/hr, and 5.4 rem/hr for mis-steering and maximum credible beam losses, respectively.