1. Fassò, N. Nakao, H. Vincke Aug. 2, 2005
SLAC RP current activities in radiation simulation and possible extension to ILC
Fassò, N. Nakao, H. Vincke
Aug. 2, 2005

2. Our tools FLUKA and MARS Benchmarking
Coupled electromagnetic/hadronic cascade
Electric and magnetic fields
Complex geometries
Energy range keV to 1000 TeV
Standard simulation tools for LHC
Benchmarking
Neutron spectrometry
Activation measurements

3. Current and already planned simulation studies in RP
LCLS:
shielding
PPS stoppers
radiation damage to electronics, permanent magnets, diagnostic equipment
soil, groundwater and air activation, penetrations, maze design …..
ILC:
SC cavity dark current
radiation damage positron target, dpa calculations in collaboration with B. Wirth (LBL)

4. FLUKA modelling of the LCLS undulator
Section of the geometry
between two segments
AUTOCAD view

5. Longitudinal and vertical distribution of total dose
Longitudinal and vertical distribution of total dose. Max = 110 Mrad/day
(assuming an electron intensity of 9.16 × 1011 electron/s)

6. Transversal distribution of dose and neutron flux
At neutron flux max
At dose max

7. MARS15 Monte Carlo simulation for LCLS
Arrangement of beam line components and magnetic fields in MARS15
Secondary particle shower
By beam loss at BYD1 bending magnet
14.1 GeV electrons Bending into the beam dump

8. Prompt dose distribution in LCLS tunnel by MARS15
14.1GeV 30W beam loss at BYD1-bending magnet
Top view
Vertical

9. Residual Dose Rate & Activity around Beam Dump by MARS15
14.1GeV 5kW electron beam
Below 1 mrem/h at top concrete
Along the beam line
Perpendicular to beam line
Attenuation of residual dose rate in concrete and iron
1/100
Residual Dose Rate [mSv/h] (30-day operation 1-day cooling
3H (Tritium) & 22Na activities in soil are available from MARS15 simulation results
Activity estimation in ground water
Bottom side side forward
Bq/cm3

10. FLUKA Calculation for LCLS “Two mirror system”
Cross-sectional view through the FLUKA geometry.
FEE...Front End Enclosure; WBOR…White Beam Optic Room;
NEH…Near Experimental Hall.

11. LCLS – “Two mirror system” - cont’d
Total effective dose rate in mrem/h

12. Estimate of induced radioactivity around the FFTB dump

13. Residual radioactivity around the FFTB dump after 180 days of operation (28.5 GeV electrons on dump, 2kW)

14. Previous calculations performed for NLC by RP/SLAC
Dose to Electronics in the NLC Beam Tunnel RP Note 99–15
Soil & Groundwater Activation around the Beam Delivery System Tunnel RP Note 00-04
Evaluation of Radiological Consequences from Air Activation at NLC BDS Tunnel RP Note 00-05
Radiation Damage to Electronics Installed in Niches of the NLC Beam Tunnel RP Note 00–06

15. RADIATION DAMAGE TO ELECTRONICS IN THE BEAM TUNNEL OF THE NEXT LINEAR COLLIDER1
- Non-radiation-hard electronics could be severely
damaged unless sufficiently shielded against radiation.
- Proposal: Niches in the beam tunnel wall which are shielded by layers of polyethylene.
1 SLAC-PUB-8490

16. ILC: Possibilities for the next calculations
Soil, air and groundwater activation
Machine component activation
Detector Background
Shielding (personnel, environment, equipment)
Dumps, collimators
SC Quenching
dose rates in occupied areas
Anything else ?