Induced γ-ray emission

Vali, V.; Vali, W.

doi:10.1109/proc.1963.1677

Cited by 32 publications

(8 citation statements)

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“…(2). In effect, the time-integrated branching ratio in an ensemble of nuclei is smaller than the single particle branching ratio b 1 , thereby reducing the efficiency of the optical pumping to the target state |I .…”

Section: B Control Of the Cooperative Branching Ratiomentioning

confidence: 99%

“…Similar possibilities with nuclear systems have been considered with great interest [1][2][3][4][5][6][7][8] already shortly after the realization of the first laser in the optical band [9]. However, many quantum optical control schemes require the effective coupling of the driving field to the considered transition (Rabi frequency) to be of the same order as the relaxation rate of the same transition [10,11].…”

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confidence: 99%

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Coherent control of the cooperative branching ratio for nuclear x-ray pumping

2011

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Coherent control of nuclear pumping in a three level system driven by x-ray light is investigated. In single nuclei, the pumping performance is determined by the branching ratio of the excited state populated by the x-ray pulse. Our results are based on the observation that in ensembles of nuclei, cooperative excitation and decay leads to a greatly modified nuclear dynamics, which we characterize by a time-dependent cooperative branching ratio. We discuss prospects of steering the x-ray pumping by coherently controlling the cooperative decay. First, we study an ideal case with purely superradiant decay and perfect control of the cooperative emission. A numerical analysis of x-ray pumping in nuclear forward scattering with coherent control of the cooperative decay via externally applied magnetic fields is presented. Next, we provide an extended survey of nuclei suitable for our scheme, and propose proof-of-principle implementations already possible with typical Mössbauer nuclear systems such as 57 Fe. Finally, we discuss the application of such control techniques to the population or depletion of long-lived nuclear states. PACS numbers: 73.20.Mf, 78.70.Ck, 75.78.Jp, 76.80.+y Coherent control in quantum optics and atomic physics provides an efficient tool to investigate atomic properties and favorably manipulate the dynamics of the system alike. Similar possibilities with nuclear systems have been considered with great interest [1-8] already shortly after the realization of the first laser in the optical band [9]. However, many quantum optical control schemes require the effective coupling of the driving field to the considered transition (Rabi frequency) to be of the same order as the relaxation rate of the same transition [10,11]. Consequently it is very demanding to exploit the direct laser driving of nuclear systems experimentally. Furthermore, the dream of the nuclear laser is at present equally out of reach. The pursuit of coherent sources for wavelengths around or below 1 nm is supported however by the advent and commissioning of x-ray free electron lasers [12,13], the availability of which will stimulate the transfer of quantum optical schemes to nuclei along these lines.A different route to coherent control of nuclear dynamics which does not rely on forthcoming x-ray light sources is coherent light scattering off nuclei in the low-excitation limit [14][15][16][17][18]. In particular, coherent nuclear forward scattering (NFS) is a routine technique experimentally studied in many labs around the world. In NFS, high-frequency light such as that from a synchrotron radiation (SR) source is monochromatized at a nuclear resonance energy, and then scatters coherently off a nuclear target. As has recently been realized, while being conceptionally different from the attempts to directly transfer quantum optical schemes to the nuclear realm, NFS does allow to explore coherent control of nuclei in experimental settings already available today [19][20][21][22]. The possibility of control exploited in these works ar...

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Section: B Control Of the Cooperative Branching Ratiomentioning

confidence: 99%

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confidence: 99%

Coherent control of the cooperative branching ratio for nuclear x-ray pumping

2011

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“…Others (Rivlin, 1961;Vali andVali, 1963a, 1963b;Baldwin et al, 1963aBaldwin et al, , 1963b noted that, since nuclei could be pumped by nuclear reactions, population inversion would not require the enormous pumping power that would be needed to invert atomic transitions of comparable energy. Gain might then be easily realized from nuclei bound in crystal lattices, because the Mö ssbauer effect would enable them to interact strongly with resonant radiation, while the Borrmann effect would greatly reduce the nonresonant (loss) photoelectric and Compton interactions.…”

Section: Conceptual Overviewmentioning

confidence: 99%

“…In particular, there were proposals for closed-path arrays of crystal reflectors alternating with pumped graser bodies (Deslattes, 1968) or for bending a pumped whisker crystal into a circle (Vali and Vali, 1963b). Such concepts present obvious practical difficulties.…”

Section: E Crystals As Resonatorsmentioning

confidence: 99%

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Recoilless gamma-ray lasers

Baldwin

Solem

1997

Rev. Mod. Phys.

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This review is addressed to the development of lasers that might generate coherent radiation at ultrashort wavelengths by stimulating recoilless nuclear transitions in solids. First, the authors review the basic physics of stimulated emission, superradiance and the kinetics of lasing, with particular attention to those aspects that characterize recoilless nuclear transitions in solid hosts. Then they classify the various approaches to pumping that have been proposed for resolving the ''graser dilemma''-that the pump can destroy the conditions essential to gain-and discuss the general requirements for specification of an active nuclide and its solid host. The authors then classify and review those graser systems proposed since 1980 and prior to July 1996 in the published literature of the field, namely, (1) those that would pump directly, either with radiation or with intense bursts of neutrons; (2) those that would pump indirectly by first generating a nuclear isomer; (3) those that would eliminate the need for population inversion; and (4) several miscellaneous concepts. The significance of recent relevant experiments is described and discussed, and, finally, recommendations for future research are made. [S0034-6861(97) CONTENTS

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Theory of radiation of charged particles channeled in a crystal

Kumakhov

1977

Physica Status Solidi (b)

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The theory of a new effect is developed -spontaneous radiation of y-quanta in channeling relativistic particles. The radiation characteristics are different from the presently known types of radiation sources. Bt energies of the order of 1 GeV the radiation is characterized by wavelength 5 if. The radiation intensity is about 6 to 9 orders of magnitude higher than obtained from modern synchrotrons. l t s monochromaticity is considerably better than bremsstrahlung or synchrotron radiation. The radiation is fairly well polarized. I n the quantum treatment, the radiation is caused by transitions between levels, which are formed in channeling in the fields of atomic planes and rows. A classical and quantum calculatlon of the radiation intensity is presented. At a current of about 100 pA and a target thickness of 1000 pm, about 10l8 to lOlS quanta/s are radiated. The spectral density of the radiation is considerably higher than that of any known kind of radiation. It is suggested that the radiation might be used to influence selectively nuclear transitions and to produce a y-laser. This radiation can be used to study the crystal lattice potentials, measure the particle energy, and so on. Dispersion is studied. The possibility of enhancing the induced radiation is shown. A number of studies on light channeled particles are analysed.

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Induced γ-ray emission

Cited by 32 publications

References 1 publication

Coherent control of the cooperative branching ratio for nuclear x-ray pumping

Coherent control of the cooperative branching ratio for nuclear x-ray pumping

Recoilless gamma-ray lasers

Theory of radiation of charged particles channeled in a crystal

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