Nuclear Data Section
International Atomic Energy Agency
P.O.Box 100, A-1400 Vienna, Austria
Memo CP-D/590
Date:
To:
From:

13 October 2009
Distribution
N. Otsuka

Subject:
Reference:

Self-indication and raw data
WP1999-7, CP-D/584

There are 6 entries (40876, 40884, 41151, 41290, 41394, 41426) compiled with SIF
in SF6. All were measured by Yu. V. Grigor’ev et al. at Dubna and Obninsk reactors.
Because the definition of the self-indication is not very clear from the entry (whichwas proposed in WP1999-7) and it is closely related to transmission and reaction yield,
I would propose to collect explanation of these quantities into a new LEXFOR entry“Transmission and Reaction Yield”.

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Draft of new LEXFOR entry “Transmission and Reaction Yield”)

Transmission and Reaction Yield
Definition: Transmission T(E) and reaction yield Y x (E) are defined by
T ( E ) = exp[− nT σ T (E )]Yx (E ) = [1 − exp(− nT σ T ( E ) )]σ x (E )(x = capture, fission etc.)
σ T (E ), where, n T is the sample thickness in nuclei/barn, σ T (E) and σ x (E) are the Dopplerbroadened total cross section and cross section for the channel x.
REACTION coding:(…(N,TOT)),,TRN)

Transmission(…(N,G)…),,TRN,,RYL) Capture yield
Independent variables:
Incident energy (EN etc.)
Sample thickness (THICKNESS)
Sample temperature (TEMP)Units: NO-DIM
Usually these data are reduced from raw data as follows:
C ' − B' x
C 'in − B'in
Yx = N x x
T = NTC 'ϕ − B 'ϕ
C ' out − B' out, where in, out, r and φ stand for sample-in, sample-out, reaction channel and beam
flux measurement, N T and N x are normalization factors, and C’ and B’ denote countand background count corrected for dead time, respectively. In addition, reaction yieldfrom incident particles scattered before inducing the reaction of type x should besubtracted from Y x . Corrections applied to compiled data should be described under
keyword CORRECTION. If appropriate corrections are not applied to data received bycompilers, it should be indicated by RAW in SF8. (See Raw Data.).
In neutron time-of-flight measurements, the observed value broadened by resolutionfunction is defined by
F (T ) = ∫ R(T , E ) f (E )dE, where T is the channel number (e.g. time-of-flight channel) and R (T,E) is theresolution function (probability to find outgoing particle having E in T).

Transmission ratio and self-indication ratio
Transmission (ratio) T g and self-indication (ratio) R gx are defined as∫ ε (E )exp[− n σ (E )]ϕ (E ) dE ∫ exp[− n σ (E )]dE / ETTg =Tg

TT~∫ ε T (E )ϕ ( E ) dETg

∫ dE / Egg∫ ε (Eγ )n σ (E )exp[− n σ (E )]ϕ (E ) dE ∫ σ (E )exp[− n σ (E )]dE / E~R gx =()()()εEnσEϕEdE∫ γ∫ σ (E ) dE / Exxx

TTx

gT

Tgx

xx

x

gg

, where ε T (E) and ε x (E) give efficiencies detectors for transmission and reaction yieldmeasurements, n x gives the sample thickness of the thin reaction target, φ(E) gives
spectrum of incoming particles. Integration is performed over a given energy range ofthe energy group g. The approximation ~ is applied when the efficiencies are regarded
as constants and the spectrum is proportional to 1/E. These ratios can be used toderive self-shielding factors in reactor physics [1,2].
REACTION coding:(…(N,TOT)),,TRN,,SPA)

Transmission (ratio)(…(N,G)…),,SIF,,SPA)

Self-indication (ratio) for capture

Independent variables:
Upper and lower boundary of incident energy (EN-MIN, EN-MAX)
Sample thickness (THICKNESS)
Sample temperature (TEMP)Units: NO-DIM
Spectrum should be explained under INC-SPECT.
Detectorγφ(E)238U

exp [-nTσT (E)]φ(E)nT (atom/b)

10Bγ(a) Transmission measurement for 238U

Detectorγ
φ(E)

238

U

exp [-nTσT (E)]φ(E)238

Unx (atom/b)γnT (atom/b)(b) Self-indication measurement for 238UReferences[1] H. Oigawa et al., J. Nucl. Sci. Technol. 28 (1991) 879[2] T. Bakalov et al., Proc. of Int. Conf. on Nuclear Cross Sections for Technology,
Knoxville, Tennessee, 22 - 26 Oct 1979, p692.