Delayed Neutrons from Fission of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="normal">U</mml:mi></mml:mrow><mml:mrow><mml:mn>235</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>

Hughes, Donald J.; Dabbs, J.W.T.; Cahn, A.; Hall, D.

doi:10.1103/physrev.73.111

Cited by 83 publications

(13 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…period with over 40% abundance (5). The total yield of delayed neutrons in Us5 fissioil is about 0.755y0 of all neutrons (4). If this 2.11 sec.…”

Section: Resultsmentioning

confidence: 99%

THE YIELD OF Cs¹³⁸ IN THERMAL NEUTRON FISSION OF U²³⁵

Bartholomew¹,

Baerg²

1956

Can. J. Chem.

View full text Add to dashboard Cite

The yield of in thermal neutron fission of U235 has been investigated using the 47r counting technique. The value obtained for the fissiorl yield is ( 7 . 2 2 3~ 0.29) yo based on a value of 6.32y0 for the fission yield of Bal'O. The halflife of Cs138 was determined and found to be 32.2f 0.1 min. INTRODUCTIONEarly radiochemical investigations of slow-neutron fissioil indicated that the familiar double-humped yield-mass curve was essentially smooth. Marked deviations from a smooth curve were definitely established, however, by Thode and co-workers (6, 11) in mass spectrometric determillations of fission product rare gases. Plausible interpretations of this fine structure have been evolved in terms of various closed shell effects on the fission process and also on the post-fission processes.Pappas (7) has made quantitative estimates of the U235 fission yields in the heavy mass wing, based on the concept of primary prompt neutron emission from each fission fragment followed by additional prompt neutron emission from those fragments with 1, 3, 5, or 7 neutrons outside the closed 82 neutron shell. T h e estimates include, in addition, effects due to delayed neutron emission. Although only a few delayed neutron emitters have been identified, it is expected that all of them belong to a group of nuclides which have 2, 4, or 6 neutrons in excess of closed shells. The mass 138 chain is of particular interest in this connection because it may be expected to exhibit a n enhanced fission yield due to delayed neutron emission from IL3Y Pappas (7) has estimated this effect a t about 5.5% of the yield estimate based on primary and secondary prompt neutron emission alone. In spite of this interesting possibility it is only very recently that measurements have been made on the yield of the mass 138 chain. We have made radiochemical measurements of the yield of 32 min. C S '~~, relative to that of 12.8 day Ba140, in the thermal neutron fission of US5, using 47r counting techniques.The formation of Cs138 in fission may be represented as follows:

show abstract

“…period with over 40% abundance (5). The total yield of delayed neutrons in Us5 fissioil is about 0.755y0 of all neutrons (4). If this 2.11 sec.…”

Section: Resultsmentioning

confidence: 99%

THE YIELD OF Cs¹³⁸ IN THERMAL NEUTRON FISSION OF U²³⁵

Bartholomew¹,

Baerg²

1956

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…рис. 43 33 . Хотя мы ещё многого не знаем относительно структуры оболочек, но -из рассмотрения сферической-потенциальной ямы, -проведённого-в разделе :11;: мы видели:, ..что порядок уровней в -деформированном ядре сильно отличается от обычного.…”

Section: поперечные сеченияunclassified

“…При возбуждениях, превышающих барьер на несколько Мэв (но меньше энергии связи двух нейтронов), следует ожи-дать плавной зависимости сечения деления от энергии. Поперечное сече-ние деления снова возрастает, если возбуждение так велико, что деление может произойти после испускания промежуточным ядром одного или бо-лее нейтронов *>,-ПЪразительный пример возможного влияния внутреннего состояния ядра на вероятность деления описан Стритом, Гиорсо и Томсоном 92 43. Зависимость сечения деления нейтронами от энергии для пяти делящихся элементов 28 .…”

Section: нормальный квадрупольunclassified