The double-energy double-velocity (2E-2v) method allows assessing fission-fragment mass yields prior to and after prompt neutron emission with high resolution. It is, therefore, considered as a complementary technique to assess average prompt neutron multiplicity as a function of fragment properties. We have studied the intrinsic features of the 2E-2v method by means of event-wise generated fission-fragment data and found short-comings in the method itself as well as in some common practice of application. We find that the 2E-2v method leads to large deviations in the correlation between the prompt neutron multiplicity and pre-neutron mass, which deforms and exaggerates the so called 'sawtooth' shape of v(A). We have identified the treatment of prompt neutron emission from the fragments as the origin of the problem. The intrinsic nature of this deficiency risks to render 2E-2v experiments less interesting. We suggest a method to correct the 2E-2v data that can even be applied on existing measurements.

JANSSON K.;  AL-ADILI A.;  ANDERSSON SUNDÉN E.;  GÖÖK Alf;  OBERSTEDT Stephan;  POMP S.; 

2018-08-31

SPRINGER

JRC108095

1434-6001,   

https://publications.jrc.ec.europa.eu/repository/handle/JRC108095,   

10.1140/epja/i2018-12544-0,