beam loads & dump concepts t. kramer, b. goddard, m. benedikt, hel. vincke

Beam loads & dump concepts

T. Kramer, B. Goddard, M. Benedikt, Hel. Vincke

29/05/2008 T. Kramer AB-BT-TL 2

Processes & MethodsProcesses & 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


Main PS2 design parameters and key assumptions for the dump load calculations

Assumed 200 days of operation

Maximum of 1.08 x 1021 protons /y

All calculations are done in a rather conservative way

Injection energy (T) GeV 4

Extraction energy (T) GeV 50

Maximum beam intensity p+ 1.51014

Minimum cycle period to 50 GeV s 2.4

Maximum norm.emittance (H-V) .mm.mrad 15.0-8.0

Cycles per year 7,200,000

Protons accelerated per year p+ 1.081021


OOperational Aspects (1/2) - Dump Functionalitiesperational 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’


H- Injection (unstripped beam and setting-up)

6.4x1019 p.a. (5.92%) @ 4 GeV

Emergency beam abort assumed 0.5% of cycles dumped 5.4x1018 (0.5%) particles p.a. (50% @ 4-

20 GeV)

Machine setting up 6 days (2 per beam); 20% of full intensity 6.5x1018 p.a. (0.6%) (50% @ 4-20GeV)

Machine development 100h p.a. 20% of full intensity 4.3x1018 p.a. (0.4%) (50% @ 4-20 GeV)

Estimated beam loadsEstimated beam loads Particles remaining after slow extraction

Max. 1 % remaining particles; 50 GeV; operational 50% p.a.; 3.6s cycle

3.6x1018 p.a. (0.33%)

Fast injection setting up and failures 1 day p.a.; 20% dumped; 100 failures

p.a. 1.08x1018 p.a. (0.1%) @ 4 GeV

Setting up of injection transfer line 4 days p.a.; 10% intensity; 20 foil

exchange interventions; 3.06x1018 p.a. (0.28%) @ 4 GeV

Setting up of extraction transfer line 2 days p.a.; 30% intensity; 3.25x1018 p.a. (0.3%) @ 50 GeV


Unstripped beam 2 kW unstripped H-,H0 (95% efficiency) 5.4x1019 p.a. (5%)

Yearly startup 8x1018 p.a. (0.75%)

Setting up Injection systems / foil exchange 1.8x1018 p.a. (0.16%)

Main Issue: Beam Loads from HMain Issue: Beam Loads from H-- Injection Injection


Operational aspects (2/2): Operational aspects (2/2): Internal emergency dump Internal emergency dump

Possible solution:

Internal dump only takes the beam which really has to go there (8x1018 4-20 GeV + 2.7x1018 p@50 GeV p.a.)

Whenever there is time to extract the beam safely, a beam line dump is used (slow extraction, machine development, setting-up, ....

(5.5x1018 @ 20-50 GeV + 6.9x1018 @ 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


Summary of beam loadsSummary of beam loads

Function E [GeV] Load [p+]% oftotal

Possible beam destinations

Injection transfer

line dump

Internal fast injection

dump

Internal or external H- dump

Internal or external

emergency dump

Injection line setting up 4 3.1x1018 0.28 X

Fast injection setting up 4 1.1x1018 0.10 X

H- injection losses 4 6.4x1019 5.92 X

Emergency abort 4-20 2.7x1018 0.25 X

Machine development 4-20 2.2x1018 0.20 X

Machine setting up 4-20 3.3x1018 0.30 X

Function E [GeV] Load [p+] % of total

Possible beam destinations

Internal or external emergency dump

External beamline or transfer line dump

Emergency abort 20-50 2.7x1018 0.25 X

Machine development 20-50 2.2x1018 0.20 X X

Machine setting up 20-50 3.3x1018 0.30 X X

Extraction line setting up 50 3.3x1018 0.30 X

Slow extraction beam 50 3.6x1018 0.33 X X

Table 1: Beam loads @ “high Energy”

Table 2: Beam loads @ “low Energy”


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 overviewSchematic overview


Conclusion & SummaryConclusion & SummaryPS2 dump

Beam loads [p+ /y]

4 GeV 4-20 GeV 20-50 GeV 50 GeV

1. PS2 injection transfer line dump 3.1x1018 - - -

2. Internal fast injection dump 1.1x1018 - - -

3. External H- injection dump 6.4x1019 - - -

4. Internal emergency dump - 8.2x1018 2.7x1018 -

5. External beamline dump - - 5.5x1018 6.9x1018

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

TungstenCopper

AluminumIron

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 hour 1 day 1 week 1 month 1 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

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1h 1d 1w 1m 1y

Resi

dual

dos

e ra

te (u

Sv/h

)

Cooling time

PS2 injection transfer line dump

Internal fast injection dump

External H- injection dump

Internal emergency dump

External beamline dump

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1h 1d 1w 1m 1y

Resi

dual

dos

e ra

te (u

Sv/h

)

Cooling time






SPS after shutdown 2006

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)

1.E+02

1.E+03

1.E+04

1.E+05

1.E+06

1h 1d 1w 1m 1y

Resi

dual

dos

e ra

te (u

Sv/h

)

Cooling time






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 • ...

beam loads & dump concepts t. kramer, b. goddard, m. benedikt, hel. vincke

Documents

kramer abbt

beam line dump

gevemergency beam

gevestimated beam

beam loads dump concepts

h injection unstripped

high beam load

summary of beam loadstable