PROBLEM TO BE SOLVED: To obtain a scattering-body switching device capable of avoiding increase in size, turbulence of irradiation and a collision between scattering bodies, so as to accurately replacing the scattering bodies.SOLUTION: The scattering-body switching device includes: a vacuum chamber 42 housing a plurality of scattering bodies 2 a drive mechanism 3 which has drive rods 3b each extending into the vacuum chamber 42 toward a center axis X42 from different directions outside the vacuum chamber 42 on a first plane vertical to the center axis X42 and having the scattering bodies 2 connected to the leading end thereof, thereby linearly driving the scattering bodies 2 to either of a use position or a retracted position separated from the use position and stoppers 5 connected to the drive rods 3b corresponding to the respective scattering bodies 2 for cooperating with the scattering bodies, so as to prevent the collision of the scattering body with the other scattering body. The respective drive regions of the stoppers 5 are set outside the vacuum chamber 42 parallel to the first plane and separated from the center axis X42.COPYRIGHT: (C)2013,JPO&INPIT【課題】大きさの増大や照射の乱れ、および散乱体同士の衝突を回避して、的確に散乱体の入れ替えができる散乱体切替装置を得ることを目的とする。【解決手段】複数の散乱体2を格納する真空チェンバ42と、中心軸X42に垂直な第1の平面内で、真空チェンバ42の外側の互いに異なる方向から中心軸X42に向かって真空チェンバ42内に延伸し、先端に散乱体3が接続された駆動ロッド3bを備え、散乱体2を、それぞれ使用位置、または使用位置から離れた退避位置のいずれか一方に直線駆動する駆動機構3と、散乱体2のそれぞれに対応する駆動ロッド3bに連結され、当該散乱体に連動して当該散乱体の他の散乱体への衝突を防止するストッパ5と、を備え、ストッパ5のそれぞれの駆動領域を、第1の平面と平行で中心軸X42から離れた真空チェンバ42の外側に設定する。【選択図】図1
