Proton radiography is a well-established technique for measuring electromagnetic fields in high-energy-density plasmas. Fusion reactions producing monoenergetic particles, such as D3He, are commonly used as a source, produced by a capsule implosion. Using smaller capsules for radiography applications is advantageous as the source size decreases, but on the National Ignition Facility (NIF), this can introduce complications from increasing blow-by light, since the phase plate focal spot size is much larger than the capsules. We report a demonstration of backlighter targets where a "Saturn" ring is placed around the capsule to block this light. The nuclear performance of the backlighters is unperturbed by the addition of a ring. We also test a ring with an equatorial cutout, which severely affects the proton emission and is not viable for radiography applications. These results demonstrate the general viability of Saturn ring backlighter targets for use on the NIF.

中文翻译：

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国家点火装置的土星环质子背光源

质子射线照相术是一种成熟的技术，用于测量高能量密度等离子体中的电磁场。产生单能粒子（如 D3He）的聚变反应通常用作由胶囊内爆产生的源。随着光源尺寸的减小，在射线照相应用中使用较小的胶囊是有利的，但在国家点火设施 (NIF) 上，这可能会因增加漏光而带来并发症，因为相位板焦斑尺寸比胶囊大得多。我们报告了背光目标的演示，其中在胶囊周围放置了一个“土星”环来阻挡这种光线。背光源的核性能不受添加环的影响。我们还测试了一个带有赤道切口的戒指，这严重影响质子发射并且不适用于射线照相应用。这些结果证明了土星环背光目标在 NIF 上使用的普遍可行性。