Identification of the New Isotope ^{244}Md

Area of Science:

• Nuclear Physics
• Radiochemistry

Background:

• The synthesis and characterization of new isotopes are crucial for understanding nuclear structure and stability.
• Superheavy elements provide unique insights into nuclear forces and decay modes.

Purpose of the Study:

• To synthesize the isotope 244-Mendelevium (Md) via the 209-Bismuth (Bi) + 40-Argon (Ar) reaction.
• To measure the decay properties, specifically alpha decay energies and half-lives, of 244-Md.
• To confirm the mass number assignment of the synthesized isotope and search for evidence of other decay products.

Main Methods:

• Irradiation of a 209-Bi target with 40-Ar ions at Lawrence Berkeley National Laboratory's 88-inch cyclotron.
• Separation of reaction products using the Berkeley Gas-filled Separator.
• Identification of nuclides using an apparatus for the identification of nuclide A.
• Measurement of alpha particle energies and decay times.

Main Results:

• Successful production of the isotope 244-Md.
• Measured alpha decay energies for 244-Md: 8.66(2) MeV and 8.31(2) MeV.
• Determined half-lives for 244-Md: 0.4_{-0.1}^{+0.4} s and approximately 6 s.
• Confirmed the mass number A=244 for the synthesized Mendelevium isotope.
• Observed first evidence for the alpha decay of 236-Berkelium (Bk).

Conclusions:

• The decay properties of 244-Md were characterized, providing valuable data for nuclear models.
• The experimental results confirm the successful synthesis and identification of 244-Md.
• The observation of 236-Bk alpha decay opens new avenues for research in this region of the nuclear chart.