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USNDP

7He (1974AJ01)


(See the Isobar Diagram for 7He)

Mass of 7He: From the Q of the 7Li(t, 3He)7He reaction, the atomic mass excess of 7He is 26.11 ± 0.03 MeV. 7He is unbound with respect to 6He + n by 0.44 ± 0.03 MeV (1968ST1J): Γ < 0.2 MeV (1973LI02).

GENERAL:

See (1960GO1B, 1965BO1C, 1965LA1B, 1967CO1K, 1970LO1E, 1972CA37, 1972GA1L, 1972PN1A, 1973JU2A) and (1966LA04).

1. 7Li(t, 3He)7He Qm = -11.18
Q0 = -11.18 ± 0.03 (1968ST1J).

The 3He particles to the ground state of 7He have been observed at Et = 22 MeV. The width of the ground state is 160 ± 30 keV; for a radius of 2.2 fm and ln = 1, this width is 0.22 of the Wigner limit. The angular distribution is peaked in the forward direction. No other states of 7He were observed for Ex < 2.4 MeV (1967ST04, 1968ST1J). See also (1968CE1A).

2. 7Li(n, p)7He Qm = -10.42

At En = 14.8 MeV, a proton group is reported corresponding to 7Heg.s.: Γ < 0.2 MeV (1973LI02). See also (1967ME11, 1971KO24) and 8Li.

3. 9Be(n, 3He)7He Qm = -17.20

Not reported.