Beam loads & dump concepts T. Kramer, B. Goddard, M. Benedikt, Hel. Vincke

29/05/2008 T. Kramer AB-BT-TL 2 Processes & Methods We started with worst case assumptions to keep the full flexibility for operations If process shows a non-feasibility or a progressive scale of prices, “settings” have to be re-evaluated  Identification of functionalities  Beam loads for functionalities  Dump concept

29/05/2008 T. Kramer AB-BT-TL 3 Main PS2 design parameters and key assumptions for the dump load calculations Assumed 200 days of operation Maximum of 1.08 x protons /y All calculations are done in a rather conservative way Injection energy (T)GeV4 Extraction energy (T)GeV50 Maximum beam intensity p+p+ 1.5  Minimum cycle period to 50 GeVs2.4 Maximum norm.emittance (H-V) .mm.mrad Cycles per year7,200,000 Protons accelerated per year p+p  10 21

29/05/2008 T. Kramer AB-BT-TL 4 O perational Aspects (1/2) - Dump Functionalities Injection line setting up Fast injection setting up H- Injection Emergency abort Machine development Machine setting up Extraction line setting up Slow extraction ‘remaining beam’

29/05/2008 T. Kramer AB-BT-TL 5 H- Injection (unstripped beam and setting-up) 6.4x10 19 p.a. 4 GeV Emergency beam abort assumed 0.5% of cycles dumped 5.4x10 18 (0.5%) particles p.a GeV) Machine setting up 6 days (2 per beam); 20% of full intensity 6.5x10 18 p.a. (0.6%) 4-20GeV) Machine development 100h p.a. 20% of full intensity 4.3x10 18 p.a. (0.4%) 4-20 GeV) Estimated beam loads Particles remaining after slow extraction Max. 1 % remaining particles; 50 GeV; operational 50% p.a.; 3.6s cycle 3.6x10 18 p.a. (0.33%) Fast injection setting up and failures 1 day p.a.; 20% dumped; 100 failures p.a. 1.08x10 18 p.a. 4 GeV Setting up of injection transfer line 4 days p.a.; 10% intensity; 20 foil exchange interventions; 3.06x10 18 p.a. 4 GeV Setting up of extraction transfer line 2 days p.a.; 30% intensity; 3.25x10 18 p.a. 50 GeV

29/05/2008 T. Kramer AB-BT-TL 6 Unstripped beam 2 kW unstripped H -,H 0 (95% efficiency) 5.4x10 19 p.a. (5%) Yearly startup 8x10 18 p.a. (0.75%) Setting up Injection systems / foil exchange 1.8x10 18 p.a. (0.16%) Main Issue: Beam Loads from H - Injection

29/05/2008 T. Kramer AB-BT-TL 7 Operational aspects (2/2): Internal emergency dump Possible solution: Internal dump only takes the beam which really has to go there  (8x GeV + 2.7x10 18 GeV p.a.) Whenever there is time to extract the beam safely, a beam line dump is used (slow extraction, machine development, setting-up,....  (5.5x GeV + 6.9x10 50GeV p.a. ) External dump at end of a beamline to a well-shielded area? Advantages System is easier to build, cheaper, desirable from point of operations, “some internal dump” to set up the extraction is anyway needed Disadvantage If operated like the SPS dump a very high beam load is expected - Radiation source within the machine

29/05/2008 T. Kramer AB-BT-TL 8 Summary of beam loads FunctionE [GeV]Load [p + ] % of total Possible beam destinations Injection transfer line dump Internal fast injection dump Internal or external H - dump Internal or external emergency dump Injection line setting up43.1x X Fast injection setting up41.1x X H - injection losses46.4x X Emergency abort x X Machine development x X Machine setting up x X FunctionE [GeV]Load [p + ]% of total Possible beam destinations Internal or external emergency dump External beamline or transfer line dump Emergency abort x X Machine development x XX Machine setting up x XX Extraction line setting up503.3x X Slow extraction beam503.6x XX Table 1: Beam “high Energy” Table 2: Beam “low Energy”

29/05/2008 T. Kramer AB-BT-TL 9 External beam line dump PS2 extraction line dump TED External H- injection dump PS2 injection transfer line dump TED(s) Internal fast injection dump Internal emergency dump SPS TT12 EAs PS2 TT10 from SPL Schematic overview

29/05/2008 T. Kramer AB-BT-TL 10 Conclusion & Summary PS2 dump Beam loads [p + /y] 4 GeV4-20 GeV20-50 GeV50 GeV 1. PS2 injection transfer line dump3.1x Internal fast injection dump1.1x External H - injection dump6.4x Internal emergency dump-8.2x x External beamline dump--5.5x x10 18 Main Issue: H - dump Different dumps to be used in main operations (internal/external) No “showstoppers”

Residual dose rate to be expected around the various beam dumps Study is based on activation calculations of a TED beam stopper The TED beam stopper is used in the SPS beam extraction lines to the CNGS/LHC A similar beam absorber is used as dump in the SPS Although this type dump is often used, it is not the ideal choise to minimize the production of residual dose rate Carbon Tungsten Copper Aluminum Iron Dimensions: Length: 430 cm Diameter: 96 cm Beam TED in TT40 tunnel (SPS extraction line) Area used for calculations

Irradiation and cool down parameters used for the calculations TED Irradiation: 10 years of operation consisting each of 200 days of beam operation and 165 days shutdown Residual dose rates were calculated for 5 different cool down periods after the last 200 days of irradiation 1 hour1 day 1 week1 month1 year

Detailed results will be presented for the external beam line dump (scenario showing highest radiation levels) The residual dose rate results for the other four dumps will be presented in a summarized way. Results

Residual dose rate seen around the external beam dump after 10 years of operation and a cool down period of 1 hour

Residual dose rate seen around the external beam dump after 10 years of operation and a cool down period of 1 day

Residual dose rate seen around the external beam dump after 10 years of operation and a cool down period of 1 week

Residual dose rate seen around the external beam dump after 10 years of operation and a cool down period of 1 month

Residual dose rate seen around the external beam dump after 10 years of operation and a cool down period of 1 year

Summurized results for all beam dumps

Residual dose rate seen at the side of the TED Dose rate at 1 m distance is approximately a factor three below the shown values Dose rate is higher than the one seen at SPS high energy dump Dose rate is lower than the one seen at SPS high energy dump

Residual dose rate seen at the hot spot of the TED (beam entry point) Dose rate is higher than the one seen at SPS high energy dump Dose rate is lower than the one seen at SPS high energy dump

Summary Significant effort has to be put into the design of the dumps and its surroundings External dumps must be designed with a bigger graphite core surrounded by heavy shielding. TED like beam dump is not sufficient. Design considerations for internal dumps: Design of internal beam dumps needs to be optimized in terms of residual radiation reduction (e.g.: marble layer). Bypass tunnel, or larger tunnel section around dump allowing to place shielding between dump and passage. Residual dose rate calculations showed that radiation levels in the surroundings of the external beam dumps and the internal emergency dumps are higher than those seen around the SPS beam dump. Operation of the two other internal dumps cause lower dose rates than seen around the SPS beam dumps Conclusion

General radiation protection issues to be considered for the PS2 project Taking into account the given annual intensity and energy of the PS2 beam, the potential to activate material, air or water will be three times higher than in the case of the CNGS facility. For the realization of the PS2 project significant effort is required to comply with the given Radiation Protection constraints. E.g.: Remote control possibilities in high radioactive areas Radioactive air and water management Radioactive material handling and waste management Shielding...