Emission of Long-Range Alpha Particles in the Spontaneous Fission ofCf252

It is generally agreed that the long-range alpha particles of fission are set free before the fragment nuclei have acquired more than a small fraction of their final energy of separation, but whether the alpha particle is liberated before the instant of scission, at that instant, or from one of the fragment nuclei very shortly thereafter, has remained an open question. Each of these views has been seriously advocated. These various hypotheses are examined in relation to recently published information regarding the distribution of mass in low-eneigy ternary fission, and other considerations, and it is suggested that the hypothesis having the strongest claim to attention is that which assumes that the alpha particles originate in the heavy fragments exclusively, being liberated, very shortly after the instant of scission, with probability not much less than unity, from fragment nuclei of low yield and small neutron excess. Conclusions which would follow, if this hypothesis were accepted, are indicated, and possible experimental tests of these conclusions are suggested.

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Spontaneous fission of Cm244 with emission of a long-range alpha particle

Soviet Atomic Energy ◽

10.1007/bf01116155 ◽

1964 ◽

Vol 16 (2) ◽

pp. 170-171 ◽

Cited By ~ 3

Author(s):

L. Z. Malkin ◽

I. D. Alkhazov ◽

A. S. Krisvokhatskii ◽

K. A. Petrzhak ◽

L. M. Belov

Keyword(s):

Long Range ◽

Alpha Particle ◽

Spontaneous Fission

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XLIII. Long-range alpha particles from thorium

The London Edinburgh and Dublin Philosophical Magazine and Journal of Science ◽

10.1080/14786440408635510 ◽

1916 ◽

Vol 31 (184) ◽

pp. 379-386 ◽

Cited By ~ 21

Author(s):

Ernest Rutherford ◽

A.B. Wood

Keyword(s):

Long Range ◽

Alpha Particles

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APPLICABILITY OF PARALLEL PLATE AVALANCHE COUNTERS TO SPONTANEOUS FISSION FROM 252Cf

International Journal of Modern Physics E ◽

10.1142/s0218301312500528 ◽

2012 ◽

Vol 21 (04) ◽

pp. 1250052

Author(s):

ZAFAR YASIN ◽

KURT HANSEN ◽

MAGNUS LUNDIN ◽

ROGER RASSOL ◽

LENNART ISAKSSON ◽

...

Keyword(s):

Time Resolution ◽

Spontaneous Fission ◽

Parallel Plate ◽

Pulse Height ◽

Time Spectrum ◽

Computer Code ◽

Reaction Chamber ◽

Alpha Particles ◽

Good Time ◽

Pulse Height Spectrum

The construction and performance of the parallel plate avalanche counters (PPACs) using a spontaneous fission source 252 Cf is described in this paper. The parallel plate circular electrodes are made of aluminum foils having a thickness less than ten microns. After fabrication, the detectors and the source are mounted inside a reaction chamber, the source between the two detectors. A low pressure is created inside the chamber using isobutane ( C 4 H 10) and a high voltage is applied to the electrodes. The detectors are first operated at different pressures and voltages to find the optimum values of the pressure and the voltage. This is necessary to avoid the sparking threshold, to achieve a good time resolution and to keep the gain of the detectors high and constant. The PPACs are operated in 2π- and 4π-geometries. In 4π-geometry the detectors are allowed to function in coincidence and noncoincidence mode. The resulting pulse height and the time spectra are studied using the computer code ROOT and some conclusions are drawn from these analyses. The pulse height spectrum shows a clear separation between the fission fragments and the alpha particles and the time spectrum indicates a good intrinsic time resolution, 0.76 ns.

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