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Gadolinium-157 (¹⁵⁷Gd)

Gadolinium-157 (¹⁵⁷Gd) adalah isotop stabil gadolinium dengan 64 proton dan 93 neutron (nomor massa 157). Kelimpahan alaminya 0.156 57(17).

Data nuklida

Unsur: Gadolinium (Gd, Z = 64)
Nomor massa (A): 157
Proton (Z): 64
Neutron (N): 93
Massa atom: 156.923967424 ± 0.000001048 u
Waktu paruh: Stabil
Mode peluruhan: Tidak meluruh
Kelimpahan alami: 0.156 57(17)
Tahun penemuan: 1933
Sumber data: IAEA Atomic Mass Data Center (NUBASE) and IUPAC CIAAW, via PubChem

The lunar surface is continuously exposed to cosmic radiation, and the interaction between planetary material and cosmic rays produces secondary neutrons. The neutron flux can be investigated using the large neutron capture cross sections of 149Sm, 155Gd, and 157Gd. For example, 157Gd will absorb neutrons and be converted to 158Gd. On a cross plot of n(158Gd)/n(160Gd) isotope-amount ratio and n(157Gd)/n(160Gd) isotope-amount ratio (Fig. IUPAC.64.1), values will move from the lower right corner to the upper left corner of the cross plot with increasing time or increasing flux.
The addition of 157Gd to Neutron Capture Therapy (NCT) has been shown to be more effective at targeting tumors than the previous method of using only 10B for the treatment (Fig. IUPAC.64.2). 153Gd (with a half-life of 0.66 years) is used in the production of photon line sources (an optical source that emits one or more spectrally narrow lines as opposed to a continuous spectrum) to manufacture 153Gd line sources. 153Gd is also used as a photon source of the dual-photon absorptiometry (DPA) technique that is used to measure bone mineral content (BMC). Studies for this technique have been conducted in horses and humans,.