JAEA：核物質を非破壊で検知：低コストで不審物検査（動画）：
JAEA:Non-destructive detection of nuclear: suspicious object inspection：
JAEA：核材料无损检测：低成本可疑物体检测
―低コストで可搬性に優れた核物質検知装置を開発―
JAEA：
空港等の運輸関連施設では、荷物に隠された核物質を検知する必要があります。
核物質検知装置は高価：
対象物に放射線を照射して調べるアクティブ装置が最も高性能。
しかし、アクティブ装置は、高価かつ大型になるという問題がある。
アクティブ装置が高価な要因は、「放射線発生器を組み込む必要があるため」です。
放射線発生器を低コスト化：
放射線発生器を低コスト化できれば、アクティブ装置自体を低コスト化できます。
そこで、
- 放射線源を高速回転させ、
- 放射線強度を変化させる、
- 放射線発生器（回転照射装置）を開発しました。
回転照射装置なら安価：
従来のアクティブ装置と比べ、はるかに安価・小型の回転照射装置を開発。
さらに、これを組み込んだアクティブ装置原理実証機を製作しました。
核物質検知性能を確認：
「従来のアクティブ装置と同等の検知性能を持つこと」を、実験で確認しました。
利用分野：
今後、
運輸関連施設等における検査だけでなく、
大規模イベントにおける不審物検査等での活用も期待されます。
日本原子力研究開発機構：プレス発表
https://www.jaea.go.jp/02/press2021/p21060402/
A reliable and robust non-destructive detection method for nuclear materials using a neutron source
2021.06.07
With the increase of today’s global terrorist threat,
a large-scale terrorist attack using nuclear materials
that can cause enormous damages can actually occur.
Consequently,
devices for nuclear security that are used to detect nuclear materials
have grown increasingly important.
The detection method called the active neutron method is the most potential candidate for it.
In the active neutron method,
neutrons are irradiated into a container containing nuclear materials and then measures the emitted fission neutrons.
Though a conventional active method using a D-T tube
has high performance to detect small nuclear materials, it has significant drawbacks of being massive and quite expensive.
We therefore developed a new active neutron method that does not use a D-T tube.
The new method that we call rotation method
is a novel method for detecting nuclear materials using a neutron source such as californium.
In this method,
while a neutron source is rotated rapidly nearby a measurement object, neutron measurement is carried out by synchronizing the rotation motion.
If the object contains a nuclear material, as the rotation speed increases,
the larger deformation of time distribution of neutron counts is observed, which in turn resulted to the detection of the nuclear material.
In addition to its features of low cost and portability,
this method is capable of detecting uranium that emits very few spontaneous fission neutrons.
We presented the fundamental principle of this method and its effectiveness for detecting nuclear materials through the experimental verifications.
The results of this study have been published in the Annals of Nuclear Energy entitled as “First demonstration experiment of the neutron rotation method for detecting nuclear material”.
JAEA HP Press release (Japanese only)
Press Release – JAEA Nuclear Science and Engineering Center