Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Analytic Estimation of Radioactive Contamination from Degraded
  Alphas   The high energy spectrum of alpha particles emitted from a single isotope
uniformly contaminating a bulk solid has a flat energy spectrum with a high end
cutoff energy equal to the maximal alpha kinetic energy ($T_{\alpha}$) of the
decay. In this flat region of the spectrum, we show the surface rate
$r_b\text{\,(Bq/keV-cm}^{2})$ arising from a bulk alpha contamination $\rho_b$
(Bq/cm$^3$) from a single isotope is given by $r_b =\rho_b \Delta R/ 4 \Delta E
$, where $\Delta E = E_1-E_2>0\ $ is the energy interval considered (keV) in
the flat region of the spectrum and $\Delta R = R_2-R_1$, where $R_2$ ($R_1$)
is the amount of the bulk material (cm) necessary to degrade the energy of the
alpha from $T_{\alpha}$ to $E_2$ ($E_1$). We compare our calculation to a rate
measurement of alphas from $^{147}$Sm, ($15.32\%\,\pm\,0.03\%$ of Sm($nat$) and
half life of $(1.06\,\pm\,0.01)\times\,10^{11} \text{yr}$, and find good
agreement, with the ratio between prediction to measurement of $100.2\%\pm
1.6\%\,\text{(stat)}\pm 2.1\%\,\text{(sys)}$. We derive the condition for the
flat spectrum, and also calculate the relationship between the decay rate
measured at the surface for a [near] surface contamination with an exponential
dependence on depth and an a second case of an alpha source with a thin
overcoat. While there is excellent agreement between our implementation of the
sophisticated Monte Carlo program SRIM and our intuitive model in all cases,
both fail to describe the measured energy distribution of a $^{148}$Gd alpha
source with a thin ($\sim200\mu$g/cm$^2$) Au overcoat. We discuss possible
origins of the disagreement and suggest avenues for future study.

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The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom