24 th international conference on nuclear tracks in solids bologna 1 5 9 2008
This presentation is the property of its rightful owner.
Sponsored Links
1 / 11

24 th International Conference on Nuclear Tracks in Solids Bologna, 1-5/9/2008 PowerPoint PPT Presentation


  • 105 Views
  • Uploaded on
  • Presentation posted in: General

24 th International Conference on Nuclear Tracks in Solids Bologna, 1-5/9/2008. Fragmentation cross sections of Fe 26+ , Si 14+ and C 6+ ions of 0.3  10 A GeV on polyethylene, CR39 and aluminum targets. M. Giorgini* on behalf of the Bologna group *Bologna Universit y and INFN.

Download Presentation

24 th International Conference on Nuclear Tracks in Solids Bologna, 1-5/9/2008

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


24 th international conference on nuclear tracks in solids bologna 1 5 9 2008

24th International Conference on Nuclear Tracks in SolidsBologna, 1-5/9/2008

Fragmentation cross sections of Fe26+, Si14+ and C6+ ions of 0.310 A GeV on polyethylene, CR39 and aluminum targets

M. Giorgini* on behalf of the Bologna group

*Bologna University and INFN


Motivations

MOTIVATIONS

An accurate description of the fragmentation of medium and high Z ions is important for the following reasons :

(i) to understand the effects of medium Z cosmic rays on humans

in space

(ii) for shielding in space and in accelerator environments

(iii) for radiotherapy and radioprotection purposes

(iv) to confirm the simulated data from the FLUKA* and RQMD**

(Relativistic Quantum Molecular Dynamics)Monte Carlo codes

* hep-ph/0306267

** J. Phys. Conf. Ser. 41 (2006) 519


Experimental procedure

CR39Detectors

Fragments

Survived beam

Incidentbeam

Fragments

Target

EXPERIMENTAL PROCEDURE

Beam : Fe26+ (E = 0.3 , 0.41 , 1.0 , 3.0 , 5.0 AGeV)

Si14+ (E = 1.0 , 3.0 , 5.0 AGeV)

C6+ (E = 0.29 AGeV)

CR39 sheets : area 11.5 × 11.5 cm2

thickness 0.65 mm

Targets : CH2 , Al , CR39

thickness 1 mm

After exposure, the CR39 sheets were etched in 6N NaOH aqueous solution at 70 °C for 30 h


Automatic measurements

AUTOMATIC MEASUREMENTS

Automatic image analyzer ELBEK

(A. Noll et al., Nucl. Tracks Radiat. Meas. 15 (1988) 265)

The base area, eccentricity and brightness are measured for each track

Tracking : the trajectory of each ion is followed through the stack

5 AGeV Fe26+

1 AGeV Fe26+

Number of events

Number of events

Average base areas for tracks present in at least 2 out of 3 measured CR39 sheets located before the target

Average base areas for tracks present in at least 2 out of 3 measured CR39 sheets located after the target


Total fragmentation cross section

AT ln(Nin/Nout)

rT tT NAV

stot =

TOTAL FRAGMENTATION CROSS SECTION

AT = mass number of the target

rT = density of the target

tT = thickness of the target

NAV = Avogadro's number

Nin = number of incident ions before the target

Nout = number of incident ions after the target

ZT = atomic number of the target

Ap = mass number of the beam

ro = 1.31 fm

bo = 1.0

 = 1.57

 = 1.9


Fragmentation cross sections of fe 26 on ch 2 cr39 and al

Fe26+on Al

Fe26+on CH2

Total cross section (mb)

[ Phys. Rev. C 56 (1997) 388 ]

[ Phys. Rev. C 56 (1997) 388 ]

[ Phys. Rev. C 56 (1997) 388 ]

FRAGMENTATION CROSS SECTIONS OF Fe26+ ON CH2 , CR39 AND Al

The quoted uncertainties are statistical standard deviations


Fragmentation cross sections of si 14 on ch 2 cr39 al c e h

Si14+on Al

Total cross section (mb)

Si14+on CR39

Si14+on CH2

[ Radiat. Meas. 34 (2001) 237 ]

[ Nucl. Phys. A 784 (2007) 341 ]

[ Nucl. Phys. A 784 (2007) 341 ]

[ Phys. Rev. C 39 (1989) 2222 ]

FRAGMENTATION CROSS SECTIONS OF Si14+ ON CH2 , CR39 , Al , C e H

The quoted uncertainties are statistical standard deviations


Data predictions comparison

Total cross section (mb)

[ Nucl. Phys. A 784 (2007) 341 ]

[ Phys. Rev. C 39 (1989) 2222 ]

[ Phys. Rev. C 56 (1997) 388 ]

0.29 A GeV C Present work

[ Phys. Rev. C 56 (1997) 388 ]

[ Phys. Rev. C 66 (2002) 014609 ]

Total cross section (mb)

Target mass AT

Target mass AT

DATA-PREDICTIONS COMPARISON


Partial charge changing cross sections

PARTIAL CHARGE CHANGING CROSS SECTIONS

Average base areas for tracks present in at least 2 out of 3 measured CR39 sheets located after the target

Charge resolution sZ~ 0.2e


24 th international conference on nuclear tracks in solids bologna 1 5 9 2008

PARTIAL CHARGE CHANGING CROSS SECTIONS

Partial fragmentation charge

changing cross sections for

1 AGeV Si14+ and 1 AGeV Fe26+ ions on the CH2 target

The quoted uncertainties are statistical standard deviations


Conclusions

CONCLUSIONS

The total fragmentation cross sections for Fe26+, Si14+ and C6+ ion beams of 0.3  10 A GeV energies on polyethylene, CR39 and aluminum targets were measured using CR39 nuclear track detectors

The total cross sections for all the targets and energies used in the present work do not show any observable energy dependence

There is a dependence on target mass.

The highest cross section values, observed for Al targets, are mainly due to the contribution of electromagnetic dissociation

The present data of total fragmentation cross sections are in agreement with similar experimental data in the literature

The presence of well separated fragment peaks allowed the determination of the partial fragmentation cross sections. On the average the partial cross sections decrease as the charge change DZ increases

The measured cross section data indicate that the CR39 detector can be used effectively for studies of the total and partial charge changing cross sections, also in comparison with active detectors


  • Login