The Trinity test device contained about 6 kg of plutonium as its fission source, resulting in a fission yield of 21 kT. However, only about 15% of the Pu actually underwent fission. The remaining unfissioned plutonium eventually was vaporized in the fireball and after cooling, was deposited downwind from the test site along with the various fission and activation products produced in the explosion. Using data from radiochemical analyses of soil samples collected postshot (most many years later), supplemented by model estimates of plutonium deposition density estimated from reported exposure rates at 12 h postshot, we have estimated the total activity and geographical distribution of the deposition density of this unfissioned plutonium in New Mexico. A majority (about 80%) of the unfissioned plutonium was deposited within the state of New Mexico, most in a relatively small area about 30-100 km downwind (the Chupadera Mesa area). For most of the state, the deposition density was a small fraction of the subsequent deposition density of Pu from Nevada Test Site tests (1951-1958) and later from global fallout from the large US and Russian thermonuclear tests (1952-1962). The fraction of the total unfissioned Pu that was deposited in New Mexico from Trinity was greater than the fraction of fission products deposited. Due to plutonium being highly refractory, a greater fraction of the Pu was incorporated into large particles that fell out closer to the test site as opposed to more volatile fission products (such as Cs and I) that tend to deposit on the surface of smaller particles that travel farther before depositing. The plutonium deposited as a result of the Trinity test was unlikely to have resulted in significant health risks to the downwind population.

中文翻译：

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从三位一体原子弹试验中解释未裂变钚。

Trinity 试验装置含有约 6 kg 的钚作为裂变源，裂变产量为 21 kT。然而，实际上只有大约 15% 的 Pu 发生了裂变。剩余的未裂变钚最终在火球中蒸发，冷却后与爆炸产生的各种裂变和活化产物一起从试验场顺风处沉积下来。使用从拍摄后（大多数年后）收集的土壤样品的放射化学分析数据，辅以根据报告的拍摄后 12 小时暴露率估计的钚沉积密度模型估计，我们估计了该沉积密度的总活动和地理分布新墨西哥州的未裂变钚。大部分（约 80%）未裂变钚沉积在新墨西哥州，大多数在一个相对较小的区域，约 30-100 公里的顺风处（Chupadera Mesa 地区）。对于该州的大部分地区，沉积密度只是内华达试验场试验（1951-1958 年）和后来美国和俄罗斯大型热核试验（1952-1962 年）的全球沉降物沉积密度的一小部分。从 Trinity 沉积在新墨西哥州的总未裂变 Pu 的比例大于沉积的裂变产物的比例。由于钚的高难熔性，较大部分的钚被掺入到离测试地点更近的大颗粒中，而不是更易挥发的裂变产物（例如 Cs 和 I），后者倾向于沉积在较小颗粒的表面在存款之前走得更远。