This paper presents an efficient filtering system for a metastable state-based true random number generator. To output a result with high randomness, we use loop-storage for storing the value of metastability. During the metastable state, the output value is accumulated to the storage. When the non-metastable state arises, the stored metastable value will be used for output instead of the result of the non-metastable state. As a result, we can maintain high entropy together with the original throughput.This paper presents an efficient filtering system for a metastable state-based true random number generator. To output a result with high randomness, we use loop-storage for storing the value of metastability. During the metastable state, the output value is accumulated to the storage. When the non-metastable state arises, the stored metastable value will be used for output instead of the result of the non-metastable state. As a result, we can maintain high entropy together with the original throughput.

Journal of information and communication convergence engineeringSep 30, 20120 citations

Radiative lifetimes of metastable states of Hg+ and Hg2+

Anthony G. Calamai, Charles E. Johnson

The natural radiative lifetimes of the 5${\mathit{d}}^{9} $6$ {\mathit{s}}^{2}$ ${(}^{2}$ ${\mathit{D}}_{5/2}$ and $^{2}$ ${\mathit{D}}_{3/2}$ ) metastable states of ${\mathrm{Hg}}^{+}$ as well as of the 5${\mathit{d}}^{9} $6s$ {(}^{3}$${\mathit{D}}_{2}$) metastable state of ${\mathrm{Hg}}^{2+}$ have been measured by counting for equal time intervals either the 282-, 198-, or 217-nm photons emitted when the respective metastable ions decay to the ground state. The metastable Hg ions are produced inside a cylindrical electrostatic ion trap by electron bombardment of background Hg vapor maintained at pressures ranging from 4 to 50\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ Torr. The trap consists of a 5.0-cm-diam, 7.5-cm-long cylinder with end caps plus a concentric 0.003-cm-diam central cylinder maintained at a negative potential of 140 V. Following electron impact of the Hg vapor, some of the photons emitted by the decaying metastable ion population are focused onto a narrow-bandwidth interference filter. The photons transmitted by the filter are detected by a photomultiplier tube as a function of time and generate a decay curve. However, the signal detected with the interference filter used to monitor the $^{2}$${\mathit{D}}_{3/2}$ metastable-state population consists of two exponentially decaying components, indicating the presence of another metastable state decaying through the emission of a photon within the bandpass of the filter. The second component is assumed to arise from a cascade originating with the 5${\mathit{d}}^{9}$6s6p (J=9/2) metastable state of ${\mathrm{Hg}}^{+}$ . Therefore, as dictated by the composition of the photon decay curve, the pressure-dependent decay rates of the metastable states are obtained from a least-squares fit of either a single- or double-component exponential decay to the natural logarithm of the decay curve.Mean decay rates extrapolated to zero pressure of the background Hg vapor using a straight-line least-squares fit, and the inverse of the zero-pressure intercept yields the natural radiative lifetime of the relevant metastable state. Our results for the lifetimes of the $^{2}$ ${\mathit{D}}_{5/2}$ , $^{2}$ ${\mathit{D}}_{3/2}$ , and J=9/2 metastable states of ${\mathrm{Hg}}^{+}$ are 87\ifmmode\pm\else\textpm\fi{}4, 8.8\ifmmode\pm\else\textpm\fi{}0.4, and 60\ifmmode\pm\else\textpm\fi{}6 msec, respectively, while the lifetime of the ${\mathrm{Hg}}^{2+}$ ${(}^{3}$ ${\mathit{D}}_{2}$ ) metastable state is 34\ifmmode\pm\else\textpm\fi{}3 msec.The natural radiative lifetimes of the 5${\mathit{d}}^{9}$6${\mathit{s}}^{2}$ ${(}^{2}$${\mathit{D}}_{5/2}$ and $^{2}$${\mathit{D}}_{3/2}$) metastable states of ${\mathrm{Hg}}^{+}$ as well as of the 5${\mathit{d}}^{9}$6s${(}^{3}$${\mathit{D}}_{2}$) metastable state of ${\mathrm{Hg}}^{2+}$ have been measured by counting for equal time intervals either the 282-, 198-, or 217-nm photons emitted when the respective metastable ions decay to the ground state. The metastable Hg ions are produced inside a cylindrical electrostatic ion trap by electron bombardment of background Hg vapor maintained at pressures ranging from 4 to 50\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ Torr. The trap consists of a 5.0-cm-diam, 7.5-cm-long cylinder with end caps plus a concentric 0.003-cm-diam central cylinder maintained at a negative potential of 140 V. Following electron impact of the Hg vapor, some of the photons emitted by the decaying metastable ion population are focused onto a narrow-bandwidth interference filter. The photons transmitted by the filter are detected by a photomultiplier tube as a function of time and generate a decay curve. However, the signal detected with the interference filter used to monitor the $^{2}$${\mathit{D}}_{3/2}$ metastable-state population consists of two exponentially decaying components, indicating the presence of another metastable state decaying through the emission of a photon within the bandpass of the filter. The second component is assumed to arise from a cascade originating with the 5${\mathit{d}}^{9}$6s6p (J=9/2) metastable state of ${\mathrm{Hg}}^{+}$. Therefore, as dictated by the composition of the photon decay curve, the pressure-dependent decay rates of the metastable states are obtained from a least-squares fit of either a single- or double-component exponential decay to the natural logarithm of the decay curve.Mean decay rates extrapolated to zero pressure of the background Hg vapor using a straight-line least-squares fit, and the inverse of the zero-pressure intercept yields the natural radiative lifetime of the relevant metastable state. Our results for the lifetimes of the $^{2}$${\mathit{D}}_{5/2}$, $^{2}$${\mathit{D}}_{3/2}$, and J=9/2 metastable states of ${\mathrm{Hg}}^{+}$ are 87\ifmmode\pm\else\textpm\fi{}4, 8.8\ifmmode\pm\else\textpm\fi{}0.4, and 60\ifmmode\pm\else\textpm\fi{}6 msec, respectively, while the lifetime of the ${\mathrm{Hg}}^{2+}$ ${(}^{3}$${\mathit{D}}_{2}$) metastable state is 34\ifmmode\pm\else\textpm\fi{}3 msec.

Physical Review ANov 1, 199020 citations

Lifetime of a Metastable State

I. Klik

Jan 1, 19910 citations

Decay of a Meta-stable State

Manu B. Paranjape

Cambridge University Press eBooksNov 4, 20170 citations

Dynamics of Atomic and Molecular Metastable States Produced in Electron-Bombarded Superfluid Helium

John W. Keto, M. Stockton, W. A. Fitzsimmons

We have studied the production, destruction, and lifetimes of the ${\mathrm{He}}_{2}(a{^{3}\ensuremath{\Sigma}_{\mathrm{u}}}^{+})$ and $\mathrm{He}(2^{3}S)$ metastable states of helium that are produced in electron-bombarded superfluid helium. The characteristic lifetime of a metastable molecule in the superfluid is shown to exceed 0.1 sec, while the lifetime of a metastable atom is only about 15 \ensuremath{\mu}sec. The production rates for the ${\mathrm{He}}_{2}(a{^{3}\ensuremath{\Sigma}_{\mathrm{u}}}^{+})$ and $\mathrm{He}(2^{3}S)$ metastable states are about 500 and 450 per incident 160-keV electron, respectively.We have studied the production, destruction, and lifetimes of the ${\mathrm{He}}_{2}(a{^{3}\ensuremath{\Sigma}_{\mathrm{u}}}^{+})$ and $\mathrm{He}(2^{3}S)$ metastable states of helium that are produced in electron-bombarded superfluid helium. The characteristic lifetime of a metastable molecule in the superfluid is shown to exceed 0.1 sec, while the lifetime of a metastable atom is only about 15 \ensuremath{\mu}sec. The production rates for the ${\mathrm{He}}_{2}(a{^{3}\ensuremath{\Sigma}_{\mathrm{u}}}^{+})$ and $\mathrm{He}(2^{3}S)$ metastable states are about 500 and 450 per incident 160-keV electron, respectively.

Physical Review LettersMar 27, 197248 citations

The natural radiative lifetimes of the 5${\mathit{d}}^{9}

6

{\mathit{s}}^{2}$

{(}^{2}

{\mathit{D}}_{5/2}

and

^{2}

{\mathit{D}}_{3/2}

) metastable states of

{\mathrm{Hg}}^{+}

as well as of the 5${\mathit{d}}^{9}

6s

{(}^{3}$${\mathit{D}}_{2}$) metastable state of ${\mathrm{Hg}}^{2+}$ have been measured by counting for equal time intervals either the 282-, 198-, or 217-nm photons emitted when the respective metastable ions decay to the ground state. The metastable Hg ions are produced inside a cylindrical electrostatic ion trap by electron bombardment of background Hg vapor maintained at pressures ranging from 4 to 50\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$ Torr. The trap consists of a 5.0-cm-diam, 7.5-cm-long cylinder with end caps plus a concentric 0.003-cm-diam central cylinder maintained at a negative potential of 140 V. Following electron impact of the Hg vapor, some of the photons emitted by the decaying metastable ion population are focused onto a narrow-bandwidth interference filter. The photons transmitted by the filter are detected by a photomultiplier tube as a function of time and generate a decay curve. However, the signal detected with the interference filter used to monitor the $^{2}$${\mathit{D}}_{3/2}$ metastable-state population consists of two exponentially decaying components, indicating the presence of another metastable state decaying through the emission of a photon within the bandpass of the filter. The second component is assumed to arise from a cascade originating with the 5${\mathit{d}}^{9}$6s6p (J=9/2) metastable state of

{\mathrm{Hg}}^{+}

. Therefore, as dictated by the composition of the photon decay curve, the pressure-dependent decay rates of the metastable states are obtained from a least-squares fit of either a single- or double-component exponential decay to the natural logarithm of the decay curve.Mean decay rates extrapolated to zero pressure of the background Hg vapor using a straight-line least-squares fit, and the inverse of the zero-pressure intercept yields the natural radiative lifetime of the relevant metastable state. Our results for the lifetimes of the

^{2}

{\mathit{D}}_{5/2}

^{2}

{\mathit{D}}_{3/2}

, and J=9/2 metastable states of

{\mathrm{Hg}}^{+}

are 87\ifmmode\pm\else\textpm\fi{}4, 8.8\ifmmode\pm\else\textpm\fi{}0.4, and 60\ifmmode\pm\else\textpm\fi{}6 msec, respectively, while the lifetime of the

{\mathrm{Hg}}^{2+}

{(}^{3}

{\mathit{D}}_{2}

) metastable state is 34\ifmmode\pm\else\textpm\fi{}3 msec.

We have studied the production, destruction, and lifetimes of the ${\mathrm{He}}_{2}(a{^{3}\ensuremath{\Sigma}_{\mathrm{u}}}^{+})$ and

\mathrm{He}(2^{3}S)

metastable states of helium that are produced in electron-bombarded superfluid helium. The characteristic lifetime of a metastable molecule in the superfluid is shown to exceed 0.1 sec, while the lifetime of a metastable atom is only about 15 \ensuremath{\mu}sec. The production rates for the ${\mathrm{He}}_{2}(a{^{3}\ensuremath{\Sigma}_{\mathrm{u}}}^{+})$ and

\mathrm{He}(2^{3}S)

metastable states are about 500 and 450 per incident 160-keV electron, respectively.