10He low-lying states structure uncovered by correlations

The 0+ ground state of the 10He nucleus produced in the 3H(8He,p)10He reaction was found at about $2.1\pm0.2$ MeV (\Gamma ~ 2 MeV) above the three-body 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states. We interpret the observed correlations as a coherent superposition of the broad 1- state having a maximum at energy 4-6 MeV and the 2+ state above 6 MeV, setting both on top of the 0+ state "tail". This anomalous level ordering indicates that the breakdown of the N=8 shell known in 12Be thus extends also to the 10He system.Comment: 5 pages, 5 figure

Determination of temperature dependences of Young's modulus and internal friction of fuel cladding by resonance method

We study elastic characteristics and internal friction of fuel claddings to improve computer codes for VVER-1000 fuel rods. We analytically described elastic characteristics of cladding material and obtained coefficient of the form of the first longitudinal frequency numerically. We described new measuring module for automatic acquisition data. We’ve established temperature dependences of Young’s modulus and internal friction via high-temperature facility and developed electronic module and noted maximum of these characteristics at the temperature 1160 K. It can be explained by the destruction of the texture in the material of claddings

Determination of temperature dependences of Young's modulus and internal friction of fuel cladding by resonance method

We study elastic characteristics and internal friction of fuel claddings to improve computer codes for VVER-1000 fuel rods. We analytically described elastic characteristics of cladding material and obtained coefficient of the form of the first longitudinal frequency numerically. We described new measuring module for automatic acquisition data. We’ve established temperature dependences of Young’s modulus and internal friction via high-temperature facility and developed electronic module and noted maximum of these characteristics at the temperature 1160 K. It can be explained by the destruction of the texture in the material of claddings

Recent results related to excited states of 6Be and 10He

The 1H(6Li,6Be)n charge-exchange reaction and the 3H(8He, p)10He two-neutron transfer reaction were recently carried out at the ACCULINNA fragment separator (FLNR, Dubna) to populate the ground and excited states of 6Be and 10He nuclei, respectively. The 6Be ET spectrum (ET is the 6Be energy above its 4He+p+p decay threshold) was obtained with high statistics and described by the well-known 0+ ground state of 6Be at ET = 1.37 MeV, the 2+ state at ET = 3.05 MeV and a broad structure extending from 4 to 16 MeV which could be interpreted as the isovector soft dipole mode associated with the 6Li ground state. In the 10He case the 0+ ground state was found at about 2.1(2) MeV (T ∼ 2 MeV) above the 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states: 1- (E T ∼ 5 MeV) and 2+ (ET > 6 MeV)