slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Spatial distribution and high LET component of absorbed dose measured by passive radiation monitors in ISS Russian segm PowerPoint Presentation
Download Presentation
Spatial distribution and high LET component of absorbed dose measured by passive radiation monitors in ISS Russian segm

Loading in 2 Seconds...

play fullscreen
1 / 25

Spatial distribution and high LET component of absorbed dose measured by passive radiation monitors in ISS Russian segm - PowerPoint PPT Presentation


  • 148 Views
  • Uploaded on

Spatial distribution and high LET component of absorbed dose measured by passive radiation monitors in ISS Russian segment. N. Yasuda, H. Kawashima, M. Kurano, Y. Uchihori, H. Kitamura (NIRS) Yu. Akatov, V. Shurshakov (IMBP) I. Jadrnickova, F. Spurny (NPI)

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Spatial distribution and high LET component of absorbed dose measured by passive radiation monitors in ISS Russian segm' - jenski


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
slide1

Spatial distribution and high LET component of absorbed dose measured by passive radiation monitors in ISS Russian segment

N. Yasuda, H. Kawashima, M. Kurano, Y. Uchihori, H. Kitamura (NIRS)

Yu. Akatov, V. Shurshakov (IMBP)

I. Jadrnickova, F. Spurny (NPI)

I. Kobayashi (Nagase Landauer, Ltd.)

H. Ohguchi, Y. Koguchi (Chiyoda Technol Corporation)

brados experiment
BRADOS experiment

We conducted an intercomparison experiment for passive

radiation dosimeters, Space Intercomparison/BRADOS,

  • aboard the International Space Station (Russian
  • Service Module ).

Phase-2

  • Spatial distributions of dose (rate) at 5 locations
  • Intercomparison for dosimeters of NIRS and IBMP
  • Exposure duration: 268.5 days
  • This experiment was performed in the frame work of
  • ICCHIBAN project.
passive dosimeter nirs
Passive dosimeter (NIRS)

TLD layer

Luminescence detectors: low LET

CR-39: high LET ≥ 5 keV/mm

shielding functions in the service module model
Shielding functions in the Service Module model

Less Shielded

Most Shielded

Service Module

comparison rrmd and cr 39
Comparison RRMD and CR-39

Both results are in good agreement

when they pick up only cone-shaped

etch pits.

Tawara, Doke et al., RM35(2002)119.

track taxonomy representative sample

Cone-shaped Track

Well-behaved Track

Well-behaved Stopper Track

Over-Etched Stopper Track

Track Taxonomy: Representative Sample
estimation of dose contribution of short range particles
Estimation of dose contribution of short range particles
  • AFM

Short bulk etch ~ 1 mm

  • Different types of CR-39 detectors

Different detection threshold

(HARZLAS TD-1 for >5 keV/mm)

(BARYOTRAK for higher LET particles)

calibration curves for different types of cr 39
Calibration curves for different types of CR-39

Pure CR-39

+ anti-oxidant

Pure CR-39

200eV

200eV

LET Threshold ~ 50 keV/mm

LET Threshold ~ 5 keV/mm

slide14

BARYOTRAK

B=19 mm

slide16

BARYOTRAK

B=19 mm

how to estimate
How to estimate
  • For results of BARYOTRAK,
  • The component of cone shape track is in good agreement with
  • TD-1 detector.
  • Assumption:
  • all the shallow track (green) has LET = 50 keV/mm
  • (Threshold LET: minimum case)
results
Results

Dose: x 1.7 (at least)

Dose eq: x 2.5 (at least)

QF: x 1.8 (at least)

conclusions
Conclusions
  • Dose quantities seem to be depending on local shielding environment.
  • Contribution of short range tracks was estimated with assumption (all shallow tracks = 50 keV/mm).

to dose (x 1.7)

to dose eq (x 2.5)

to averaged QF (x 1.8) (at least)

  • Contribution of short range tracks seems to be significant for dose and dose eq.

- need further systematic study coupled with accelerator exp.

(ICCHIBAN)

- need some clear definitions/guide line to verify dose amounts by CR-39

- need model calculations

r 16 detector
R-16 detector

0.5 g/cm2

3.5 g/cm2

SI1

This exp.

MATROSHKA-1

Autumn 2005

detectors
Detectors
  • R-16 (1 location) with Pille-ISS
  • DB-8 (4 locations)
  • BRADOS BOX (5 locations)

from IBMP

- TLD LiF:Mg,Ti

from NIRS

- TLD LiF:Mg,Ti

- Luxel OSL

- Glass detector

- CR-39 (HARZLAS TD-1, BARYOTRAK)

*One box was located near the R-16 detector.

*Two Pilles were located on the R-16 detector.

overview of presentation
Overview of presentation
  • Spatial dose distribution

(5 locations in Russian Service Module)

  • Comparison of luminescence detector and on board monitors (R-16, DB-8 and Pille-ISS)
  • Contribution of short range particle to dose and dose equivalent
results24
Results

* DB-8 monitors: 264, 208, 219, 146 mGy/day

~±30%

~±20%

Difference ~20%

relevant facts concerning galactic cosmic radiation
Relevant Facts concerning Galactic Cosmic Radiation
  • GCR consists of 87% protons, 11% helium nuclei (a-particles) and 1% heavy ions (Z³3).
  • While heavy ions are only 1% of flux, they make a significant (>25%) contribution to total dose equivalent.
  • Intensity of GCR is inversely proportional to level of solar activity throughout the 11 year Solar Cycle.
  • GCR is omnidirectional and isotropic.
  • Much of the GCR component is too energetic to practically shield (e.g. surrounding the spacecraft with polyethylene).
  • Leads to constant (chronic), low dose rate.

- GCR produce secondary nuclei by nuclear reactions with shielding materials / inside body.

- Short range and higher LET component will not be appeared in the active detector devices.