Laser-induced resonant absorption of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>γ</mml:mi></mml:math>radiation

Collins, C. B.; Olariu, Silviu; Petrașcu, M.; Popescu, Iovitzu

doi:10.1103/physrevc.20.1942

Cited by 17 publications

(17 citation statements)

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“…However, it also prompted a set of criticisms [5] pointing out that the integrated cross section found in [3] for resonant absorption of x rays (1 3 10 221 cm 2 keV) was ϳ7 orders of magnitude too large to be consistent with values typical of photon absorption in this mass region. Collins et al have published reports of further measurements [6], qualitatively consistent with their original result. We carried out an independent measurement designed to verify the results reported in [3,6].…”

supporting

confidence: 62%

“…Collins et al have published reports of further measurements [6], qualitatively consistent with their original result. We carried out an independent measurement designed to verify the results reported in [3,6]. Figure 1 shows the relevant energy levels and band structure in 178 Hf.…”

supporting

confidence: 62%

“…In its normal decay mode, the 16 1 isomeric state decays through an E3 transition to the 13 2 member of the K 8 band whose J p 8 2 bandhead is itself an isomer decaying with a 4-s half-life to the 8 1 member of the ground-state band, followed by a cascade to the ground state. The hypothesis offered by [3,6] for their observation of accelerated decay postulates a state (or states) of mixed K, thought to be populated from the 16 1 isomeric state by resonant absorption of x-ray photons with energies in the range 20 to 60 keV. Such an intermediate state then may decay to a lower-lying level in the K 8 band and thence to the 8 2 bandhead, whose deexcitation with a 4-s half-life cascades in a well-known way, down through the ground-state band.…”

mentioning

confidence: 99%

“…The x-ray machine used in [3,6] was operated at voltages in the range of 63-90 kV for irradiation of a target containing 6.3 3 10 14 isomeric 178 Hf nuclei distributed over a 1-cm diameter area in a sealed plastic container. Gamma-ray spectra were measured with a Ge detector and it was found that selected transitions in the normal decay cascade of the isomer increased by about 4%, implying an integrated cross section of about 10 221 cm 2 keV for absorption into and decay from the intermediate K-mixed state(s).…”

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confidence: 99%

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Search for X-Ray Induced Acceleration of the Decay of the 31-yr Isomer 178Hf Using Synchrotron Radiation

Ahmad¹,

Banar²,

Becker³

et al. 2002

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Enhanced decay of the 31-yr isomer of 178 Hf induced by x-ray irradiation has been reported previously.Here we describe an attempt to reproduce this result with an intense "white" x-ray beam from the Advanced Photon Source. No induced decay was observed. The upper limits for the energy-integrated cross sections for such a process, over the range of energies of 20-60 keV x rays, are less than 2 3 10 227 cm 2 keV, below the previously reported values by more than 5 orders of magnitude; at 8 keV the limit is 5 3 10 226 cm 2 keV.

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supporting

confidence: 62%

supporting

confidence: 62%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Search for X-Ray Induced Acceleration of the Decay of the 31-yr Isomer 178Hf Using Synchrotron Radiation

Ahmad¹,

Banar²,

Becker³

et al. 2002

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“…[1 1,13-16, [39][40][41][42][43][44], see present work [A]. [1 1,13-16, [39][40][41][42][43][44], see present work [A].…”

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confidence: 98%

Status of gamma laser problem on current moment 2000: ranging analysis and screening of gamma laser schemes on their feasibility

Karyagin

2001

Laser Optics 2000: Ultrafast Optics and Superstrong Laser Fields

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Joint theory of gamma-generation (GO) and radiation-heat regime (GG&RH) in active medium (AM) of y-taser (GL) is applied for the analyses of total world experience in the CL-problem in order to choose those nuclei-candidates, active media, GL-schemes which are indeed actual for the GL-creation. The classification of CL over a degree of the womfortable conditions for the GG is given. The GLschemes could be rsidential(Rsd) (creation of excited laser-active nuclei, ELAN, from its parents directly in the site of AM) or nonresidential(Nrsd)' (creaon of ELAN out off the AM). It has been turned out that all residentiaI part of the wod experience does not fit for the realization of GL and can be considered only as a museum-piece. Any Rsd AM on the short-lived isomers must be inevitably blasted before the beginning of the GG. That Imuseuml part includes a lot of ideas: GG on long-lived isomers; line narrowing by radio-frequency or optical fields; creation of -y-gain in the inversionless mixture of the excited and dc-excited nuclei (amplification without inversion); super-dilution of work-nuclei in a matrix via multi wave Borrman effect; non-Moessbauer active media in plasma, gas or beam with its optical laser cooling, a lot of schemes (one-stage, two-stage, two-phase, two-step, two-photon, etc.). The exception could be only Rsd GL pumped by another CL. Butthe Nrsd part of wod expeence had stood yet all stricttests of that joint theory. (induced, super-radiant, in plasma, in beam, in solid); laser cooling of atomic beam; amplification without inversion; Borrmann effect; Shpolskii effect; Moessbauer effect; hyper fine structure; laser selection (separation) of excited nuclei, isomers, isotopes; radiation-heat regime of active media of gamma-laser anomalous superdilution DTRODIJCTION The most advanced non residential (Nrsd GL (see ABSTRACT) is based on the use of the short-lived isomers (1O -1O 5) produced under nuclear pulse radiation in a special converteruf28] (alias multibeam emitter, MBE [34][35][36]) and delivered into the AM by the method SPTEN (Soft Prompt Transplantaon of Excited Nuclei) with use of the complex of measures for well generation and cooling of AM[27-36}. The enriched bunch with 90% of the Excited Laser-Active Nuclei (ELAN) is delivered into the site of AM just before the GG. Hence the Nrsd GL could be characterized by the removal from the site of AM absolutely all processes for the nuclei activation and for the inverted population creation. Only the GG and the cooling are acting in such Nrsd AM. Hence the Nrsd GL could do without use of any methods for the creation of gain in the inversionless medium because the Nrsd AM is strongly inverted before its creation, at beam-study', out off the AMs site. Owing to such circumstance the ideas developed in works[2728-36} allow to obviate the most weak flows of the OL-schemes. One such weak flow was pointed in Refsf91O,12,32,35j. It may be any process or device based on use of the hyperfine structure (HFS) directly in the AM (/n s/tm. The ideas of works[27-36J d...

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