How to Wrap Target Material

1. Introduction

  There are several disadvantages of using vials or other containers to send target materials for AMS measurement.

• Target material spreads on the wall of container, the larger the container is, the greater the amount of the material wasted
• Most of material of BeO and Al₂O₃ has very strong static electricity, it is very difficult to take sample out of container. At mean time there is high risk of sample cross contamination

It has been proved that mixing target material with binder and wrapping the mixture by the weighing paper works much better than vials and crucible. In fact, mixing the binder with the target materials for ¹⁰Be, ²⁶Al and ¹²⁹I is required to improve the ionization efficiency of the AMS machine.

2. Materials and tools needed

• The weighing paper of 3" * 3" is VWR Scientific Products, CAT no. 12578-201
• A4 paper
• Removable Magic Tape
• Niobium (Nb) powder is -325 mesh, Puratronic, 99.99%, from Alfa Aesar Stock # 40510
• Silver (Ag) powder is -325 mesh, 99.99+% from Sigma Aldrich Chem Co
• Spatula
• Parafilm

3. Mixing target material with silver/Niobium powder

• Refer to Table 1 to decide the amount of target material and Silver (Ag)/Niobium (Nb) powder to be used
• Mix target material with Silver (Ag)/Niobium (Nb) powder uniformly by spatula

Table 1 Mix binder with ¹⁰Be, ²⁶Al and ¹²⁹I

Target	BeO	Al2O3	AgI	AgCl
Prefered target weight (mg)	2 ~ 4	2 ~ 4	2 ~ 4	>5
Binder	Nb	Ag	Nb	No binder
Ratio of sample to binder by weight	1: 3.5	1:3	1:3

4. Wrapping target material using weighing paper

• Fold along the diagonal line BM (Fig. 1)
• Fold along the line DC, and let CM about 1.75" (Fig. 2)
• Put sample and binder mixture at C corner (Fig. 3)
• Fold along line EF, let EC about 1" (Fig. 4)
• Fold CB tail backward (Fig. 5)
• Fold along line HI (Fig. 6)
• Fold more till to get a packet shown in (Fig. 7)
• Seal the package by parafilm (Fig. 8)
• Cross tapping the packet in the left side of the A4 paper
• Write down, in the right side of A4 paper, the sample ID, sample weight and mixture weight of Silver (Ag)/Niobium (Nb) powder used