TNID analysis

Module type name (to be used for the module commands): tnid Note: For backwards compatibility the previous niel name can also be used.

Description

Total Non Ionising Dose (TNID) analysis modules compute the Total Non Ionising Dose (TNID). The old “NIEL” module name, which refers to the non-ionising component of the __rate__ of energy loss, is incorrect but is temporarily kept for historical and macro-file backward-compatibility reasons.

The TNID is computed with a particle-by-particle convolution of the fluence with the NIEL (taken from tabulated curves, see below). The convolution is performed at the particle trajectory crossing of user selected boundaries, in a so-called “macroscopic approach”. The TNID computation is therefore based on user-assigned NIEL coefficients at the volume interface (normally when entering the volume of interest) and not on the real material of the entered volume, so the user can obtain the TNID results at boundaries between volumes of arbitrary materials (provided the related NIEL tables are available for that material).

For information, a TNID calculation with a step by step calculation inside the volumes, is available in GRAS through the NID analysis type described further below.

NIEL curve sets

The analysis module offers a choice among several NIEL coefficient tables, obtained from the literature for different semiconductor materials. The following table summarises the available curves and their applicability.

NIEL coefficients

GRAS curve name

Materials (Specifier)

Old GRAS curve label

Particles

JPL_NRL_NASA

G4_Si

JPL_NRL_NASA_Si

p, e-, n

JPL/NRL/NASA (2003) NIEL Curves for Si - Supplied by S. Messenger (NRL)

JPL_NRL_NASA

G4_GALLIUM_ARSENIDE

JPL_NRL_NASA_GaAs

p, e-, n

JPL/NRL/NASA (2003) NIEL Curves for GaAs - Supplied by S. Messenger (NRL)

JPL_NRL_NASA

InP

JPL_NRL_NASA_InP

p, e-, n

JPL/NRL/NASA (2003) NIEL Curves for InP - Supplied by S. Messenger (NRL)

Summers

G4_GALLIUM_ARSENIDE

GaAs

p, e-

Data for GaAs from Summers. 1993

Summers

InP

InP

p, e-

Data for InP from Summers. 1993

ROSE

ROSE

p, n, pi, e-

ROSE dataset for Si from CERN RD48

SPENVIS

InP

SPENVIS

p

Data for Si supplied by Daniel Heynderickx, used in an old version of SPENVIS

Particle and energy ranges, and GRAS module behaviour:

  • For particles not included in the user selected curve set

  • Particle ignored

  • With module verboseLevel > 0 a warning is printed to log

  • For particle energy values

  • Within the available data set range –> the NIEL is computed by interpolation

  • Below the available range –> NIEL = 0 (NB: this assumes that data covers entirely the relevant low energy part of the NIEL curve)

  • Above the available range –> NIEL = NIEL at upper range limit

NIEL curve references:

JPL_NRL_NASA

  • I. Jun, M.A. Xapsos, S.R. Messenger, E.A. Burke, R.J. Walters, G.P. Summers and T. Jordan, Proton nonionizing energy loss (NIEL) for device applications, IEEE Trans. Nucl. Sci., Vol 50, 1924-1928, 2003

  • S.R. Messenger, E.A. Burke, M.A. Xapsos, G.P. Summers, R.J. Walters, I.Jun, T.M. Jordan, NIEL for heavy ions: An analytical approach, IEEE Trans. Nucl. Sci., Vol.50, 1919, 2003

  • G.P. Summers, E.A. Burke, P. Shapiro , S.R. Messenger, R.J Walters, Damage Correlations in Semiconductors exposed to Gamma, Electron and Proton Radiations, IEEE Trans. Nucl. Sci., Vol. 40, No. 6., Dec. 1993

  • Private communication from S. Messenger (NRL), c.f. Mott e- differential-scattering

  • Standard Practise for Characterizing Neutron Energy Fluence Spectra in Terms of an Equivalent Monoenergetic Neutron Fluence for Radiation Hardness Testing of Electronics, ASTM International Standard E722-94 (Re-approved 2002), American Society for Testing Materials

  • S.R. Messenger, E.A. Burke, J. Lorentzen, R.J. Walters, J.H. Warner, G.P. Summers, S.L. Murray, C.S. Murray, C.J. Crowley, N.A. Elkouh, The correlation of proton and neutron damage in photovoltaics, Proceedings 31st IEEE Photovoltaic Specialists Conference, Lake Buena Vista, Florida, Jan 3-7, 2005

  • P. Griffin (Sandia Natl. Lab), Private communication

Summers

  • G.P. Summers, E.A. Burke, P. Shapiro , S.R. Messenger, R.J Walters, “Damage Correlations in Semiconductors exposed to Gamma, Electron and Proton Radiations, IEEE Trans. Nucl. Sci., Vol. 40, No. 6., Dec. 1993

ROSE

SPENVIS

  • JPL (?)

Script example:

/gras/analysis/tnid/addModule tnidDetector
/gras/analysis/tnid/tnidDetector/addVolumeInterface Hall Detector
/gras/analysis/tnid/tnidDetector/setCurve JPL_NRL_NASA
/gras/analysis/tnid/tnidDetector/setSpecifier G4_Si
/gras/analysis/tnid/tnidDetector/setUnit MeV/g

Available Units

The module accepts as units all the G4 units under the “Dose” and “Energy*!Surface/Mass” categories. Additional GRAS units that can be used are:

  • keV/g

  • MeV/g

  • MeV/mg

  • 95MeVmb/cm2

  • Rad (rad is also accepted, but it is recommended not to be used do distinguish it from the “Angle” unit)

  • MeVcm2/g

  • MeVcm2/mg

  • keVcm2/g

  • 95MeVmb

  • 10MeVp (depends on curve selected)

  • 10MeVp/cm2 (depends on curve selected)

  • 50MeVp (depends on curve selected)

  • 50MeVp/cm2 (depends on curve selected)

  • 1MeVe (depends on curve selected)

  • 1MeVe/cm2 (depends on curve selected)

  • 1MeVn (depends on curve selected)

  • 1MeVn/cm2 (depends on curve selected)

For the units that require the definition of a target surface area, the area is automatically computed by the GRAS module, based on the inserted volume interface, but it can be set/overwritten by the user with the command setInterfaceSurfaceArea.

The units 10MeVp/cm2, 50MeVp/cm2, 1MeVe/cm2, 1MeVn/cm2 (10MeVp, 50MeVp, 1MeVe, 1MeVn) provide a normalisation of the result to an equivalent fluence(/number) of respectively 10 MeV protons, 50 MeV protons, 1 MeV electrons or 1 MeV neutrons, i.e. to the particle fluence(/number) that would produce the same TNID result. The internal conversion factors for these units are updated at each change of the NIEL curve set to use the corresponding NIEL coefficients. If the coefficients for the needed particle species are not available from the chosen NIEL curve set, the corresponding units are not available.

Specific Module commands

/gras/analysis/tnid/<moduleName>/bothWayTally [true || false]

The user can select to tally the TNID in both directions. By default, the TNID is only tallied when the particles cross the selected boundary in the direction specified by the user (i.e. the order of the volume names).

/gras/analysis/tnid/<moduleName>/pathlengthCorrection [true || false]

If true, a correction factor of 1/cos(theta) is applied, where theta is the angle between direction of the incoming particle with respect to the surface, to take account of the expected path of the particle in the target volume. This implies that the volume is assumed to be planar (because of the approximate cosine correction for the track length) and infinitesimally thin (because the particle is assumed to have constant properties, e.g. energy, inside the volume). This correction is disabled by default.

The Module is based on the Generic Factors Analysis module, so the commands specified therein are available to this module also.

Output

The Module is based on the Generic Factors Analysis module, so the output information specified therein is available to this module also.

The GFMtype is TNID.

GRAS/trunk/r2242