Loading in 5 sec....

FLUKA for accelerator radiation protection –Indian perspectivePowerPoint Presentation

FLUKA for accelerator radiation protection –Indian perspective

- By
**bary** - Follow User

- 129 Views
- Uploaded on

Download Presentation
## PowerPoint Slideshow about 'FLUKA for accelerator radiation protection –Indian perspective' - bary

**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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

### FLUKA for accelerator radiation protection –Indian perspective

### Thank you perspective

Sunil C

Accelerator Radiation Safety Section

Radiation Safety Systems Division,

Bhabha Atomic Research Centre

Accelerator Radiation Safety Section perspective

- Operational radiation protection
- Associated R&D
- Heavy Ion Accelerators (TIFR Bombay and VECC, Calcutta
- ~5-7 MeV/amu Pelletron
- ~10 MeV/amu with a superconducting linac booster
- ~100 MeV/amu superconducting cyclotron

- Electron accelerators (RRCAT Indore)
- 20 MeV Microtron to 2.5 GeV electron synchrotron
- High current industrial accelerators

Future plans perspective

- ADSS
- Proton accelerators
- 20 MeV to 1 GeV
- Swimming poll critical reactor that can also be operated in sub critical mode with 600 MeV protons incident on LBE

- 14 MeV neutron generators
- Bare
- Injectors for sub critical assemblies

- Proton accelerators

Uses of FLUKA perspective

- Routine accelerator radiation protection
- Source term calculations
- Shielding
- Induced activity
- Synchrotron hutch shielding
- Photoneutron estimation

- ADSS
- Proton accelerators
- Secondary particle dose from heavy Ion reactions
- Muon Transport and dose estimation
- Spallation yields comparison with JQMD

Heavy Ion accelerators perspective

- Neutron source term calculations
- EMPIRE, PACE (heavy ions) ALICE, PRECO (protons)
- Transport using the source.f

- BME!
- 10 MeV/amu to 100 MeV/amu
- Hauser-Feshbach for compound nucleus?

- Induced activity calculations
- Neutron spectrometry using passive techniques
- ECR ion sources
- Simulate electric fields?

20 MeV proton on Be perspective

Electron Accelerators perspective

- Photon (Bremsstrahlung) spectrometry
- High energy

- Detector response studies
- neutrons and photons

- Photoneutron spectrometry and dosimetry
- Synchrotron dosimetry
- Low energy (< 10 keV)

Photoneutrons perspective

- Contribution to the exposure in electron accelerators
- A new technique to predict the neutron spectra using empirical relations
- Spectra from FLUKA fitted to a Maxwellian
- Temperature
- Yield

- Form a couple equation to predict the GDR part of the photoneutron spectrum

- Spectra from FLUKA fitted to a Maxwellian

Check perspective

The procedure perspective

Sunil C, Sarkar P K, “Empirical estimation of photoneutron energy distribution in high energy electron accelerators”, Nuclear Instruments and Methods A 581, (2007), 844-849.

Neutrons > 50 MeV perspective

- Experimental verification using Bi fission foils, track etch membranes shows higher values when compared to FLUKA calculations.
- How much is photon induced fission?
- The cross section is 1% of neutron fission (>200 MeV)
- But at the experimental area, the photon fluence is expected to be several times higher than neutrons!
- Calculate photon induced fission using FLUKA?

Photon Transmission perspective

- 30 cm diameter and 30 cm long cylindrical detector (approximating the upper trunk of a human body) is used to count the photons.
- USRTRACK estimator tallies the photon fluence.
- Deq99 (FLUSUW) subroutine used to fold the fluence with the dose conversion coefficients to obtain ambient dose equivalent

Transmitted dose perspective

Unshielded Dose rate perspective

Variation with detector size perspective

Effect of detector size perspective

Variation with detector size perspective

Residual activity perspective

- 2.5 GeV electron incident on 10 X0 -1Xm targets.
- DPMJET activated using PHYSICS
- LAM-BIAS at 100
- Photon transport cut off to 10 MeV

Residual Activity (Bq/g) perspective

SS

2.5 GeV e perspective-, 1mA, 24 hours

Residual Nuclei perspective

- In SS, 51Cr was reported by Fasso with a higher neutron cutoff energy.
- Swanson’s technique and present calculation agree within a factor of 2; for example 57Co in Ni target, 63, 65Cu from Cu target.
- 59Fe in SS (58Fe(n,)) target in this calculation was found to be four orders less compared to that obtained by Sato and Fasso
- Most of the important nuclides formed are in the range of 200 -500 MBqW-1.

Synchrotron Hutch Shielding perspective

- Hutch design in INDUS (2.5 GeV, 1 mA)
- Bremsstrahlung mixed with SR
- Experiments claim existence of SR
- Transportation tough - low energy at the edge of FLUKA capabilities.
- Can it be simulated using FLUKA?

Heavy Ion reactions perspective

- Work done at PTB Germany
- 200 MeV 12C ions on water phantom
- Score neutron fluence and dose inside 5.7 cm spheres at different angles.
- Compare with measurements done at GSI
- Spectra from TOF (GSI measurements)
- Dose using a TEPC (PTB measurements)
- Dose using WENDI (GSI measurements)

Neutron Spectra perspective

200 MeV/amu 12C incident on 15 cm diameter cylindrical water phantom

Neutron and charged particles perspective

Charged particles perspective

Apply coincidence measurements

Response Matrices perspective

- Neutron attenuation through a target of finite thickness.
- Response of Bonner sphere type passive techniques.
- Response of liquid scintillators
- Bismuth fission detectors
- Neutron induced fission
- Photon induced fission

ADSS perspective

- A sub critical assembly driven by 14 MeV neutrons
- 256 nat.U rods inside water column, beam tube at center.
- Analog mode
- 36 hours for 106 histories !
- And still large errors (10%-30%)

Proton accelerators for ADSS perspective

- Plans to couple a sub critical reactor to a proton accelerator
- Source term for lateral shielding of the accelerator tunnel, reactor pool top
- Residual activity in LBE loop
- Activation of magnets concrete wall
- LBE window rupture due to heat load

ADSS problems perspective

- High beam current ;1-5 mA!
- Proton energies varying from 100 MeV to 1GeV
- Shielding calculations
- Reduce dose by 9 orders:- ~7 meters!

- Induced activity after several meters of water
- Explicit Transport !? Or calculate neutrons at intermediate thicknesses?

- Induced activity in magnets, concrete walls.
- Induced activity in LBE after several combinations of irradiations.

Shielding perspective

- Attenuation length from IAEA 283
- n/p ratio from FLUKA
- Multiply end result by the n/p ratio to get the transmitted dose after shield
- Biasing!

Further work perspective

- Establish attenuation curves for different shield configurations.
- Different types of concrete

- Transport neutrons through several meters of water and calculate induced activity.
- Irradiation profile, raddecay, dcytimes, usrbin

Download Presentation

Connecting to Server..