Development of a TOF-ERDA system for wide mass range

Abstract

Elastic Recoil Detection Analysis (ERDA) is a promising method for determination of light and medium chemical elements. A new ERDA system using a Time Of Flight (TOF) detector was set up to realize both higher mass resolution and lower minimum detectable amount. Ar-40 ions accelerated to 41.5 MeV by RIKEN (The Institute of Physical and Chemical Research) Linear Accelerator (RILAC) were used as a probe. A time detector composed of two Microchannel Plates (MCP) and carbon foil was installed between the sample and the Silicon Surface Barrier (SSB) detector. The time resolution of the detector was better than 100 ps. A Computer Aided Measurement And Control (CAMAC) system based on the Kakken On-line Data Acquisition (KODAQ) code was used to control the measuring system. By drawing the TOF/energy scatter plot and establishing a gate in the portion under investigation, both the energy and time spectra were obtained. The following results were also produced. (1) Hydrogen, carbon, nitrogen and oxygen were detected simultaneously. (2) The mass resolution of the system was 1.9 for Si-28. (3) Carbon, nitrogen and oxygen peaks were separated in TOF-E scatter plot, and the energy spectra of individual elements were obtained.

軽および中質量元素の分析に弾性反跳検出分析(ERDA)が有望である。より高い質量分解能とより微量な検出限度の両方を併せて実現するために、飛行時間(TOF)検出器を使用したERDAシステムを構築した。RIKEN(理化学研究所)線形加速器(RILAC)からの41.5MeVのAr-40イオンをプローブとした。マイクロチャンネルプレート(MCP)2個と炭素箔で構成した時間検出器を試料とケイ素表面障壁型(SSB)検出器の間に設置した。時間分解能100ps以上を達成した。核研オンラインデータ収集(KODAQ)コードを使用したコンピュータ支援計測制御(CAMAC)システムで計測システムを制御した。TOF対エネルギー散乱プロットを表示し、興味ある部分にゲートを設定してエネルギースペクトルと時間スペクトルを得た。以下の結果を得た。(1)水素、炭素、窒素および酸素を同時に検出した。(2)質量分解能はSi-28で1.9であった。(3)TOF-E散乱プロットにおいて炭素、窒素および酸素ピークが分離しており、元素個々のスペクトルを得た。