本文介绍的大面积低本底α闪烁计数器，其面积为111cm

2

，4

x

效率为93.8%，平均本底为0.066cpm。取

u

α

=

u

β

=2，即取两者的置信限为97.73%，测量100分钟，其最小可探测真实活性为9.58×10

-14

Ci；最小可探测真实比活性在0.2g灰样时为5.8×

M

×10

-13

Ci/kg。同时简要地说明了仪器的设计和使用原则。

A large area low background

α

scintillation counter is described. Its effective detecting area is 111cm

2

and counting efficiency with

4π

geometry is 93.8%. The average background count rate is 0.067cpm. If

U

α

=U

β

=2 (i. e. both confidence levels are 97.73%) and measuring time is 100 minutes

the minimum detectable real activity is 9.58×10

-14

Ci and in an ash specimen of 0.2g the minimum detectable real specific activity is 5.8×10

-13

Ci/kg.

The design principle and operation of this instrument are given in brief.