关于源比活度大小的问题

按照教科书 强天鹏老师主编《射线检测》第二版 第一章1.2.7中提到源比活度大小排列顺序为：Se75(1.45×10000 Ci/g)>Tm170(
1000 Ci/g)>Ir192(350 Ci/g)>Co60(50 Ci/g)>Cs137(25Ci/g).而第二章2.2.1 射线源的特性参数表 提到Se75源的比活度为中。前后矛盾了 请问下强老师 到底那个对   了 而且10年的射线考试题上也考核。请回答 谢谢 强老师。

您说得对，书上是错了。
查了很多数据库，没有找到权威数据。
哈佛大学资料库中关于Se75的词条也没有比活度数据。

现给出一组权威性待考证的比活度数据：
Co60实际比活度约为50Ci/g(1850X10Bq/g)
Ir192实际比活度约350Ci/g，(13000×109Bq/g)。
Se75比活度约为148Ci/g(5500×109Bq/g)，

又：以下资料可能有用，有兴趣不妨看一看：
RADIONUCLIDE SAFETY DATA SHEET
NUCLIDE: Se-75 FORMS: ALL SOLUBLE
________________________________________________________________
PHYSICAL CHARACTERISTICS:
HALF-LIFE: 119.78 days TYPE DECAY: e- capture
no significant beta- ; gamma: 0.066 MeV (1.02 %)
0.097 MeV (3.41 %)
0.121 MeV (16.7 %)
0.136 MeV (59.2 %)
0.265 MeV (59.8 %)
0.401 MeV (11.4 %)
Hazard category: C- level (low hazard ) : .10 uCi to 1 mCi
B - level (Moderate hazard) : > 1 mCi to 100 mCi
A - level (High hazard) : > 100 mCi
EXTERNAL RADIATION HAZARDS AND SHIELDING:
The exposure rate at 1 cm from 1 mCi is 1985 mR/hr. (ignoring photons less than 11 KeV).
The exposure rate varies directly with activity and inversely as the square of the distance. The
mount of lead necessary to reduce the exposure rate by a factor of ten is 0.5 cm.
HAZARDS IF INTERNALLY DEPOSITED:
The annual limit on oral intake (ALI) of Se75 corresponding to a whole-body gamma
exposure rate of 500 mrem/year is 54 uCi.
DOSIMETRY AND BIOASSAY REQUIREMENTS:
Film badges and dosimeter rings are required if 5 millicuries are handled at any one time
or 1 millicurie levels are handled on a frequent (daily) basis.
Urine assays may be required after spills or contamination incidents.
SPECIAL PROBLEMS AND PRECAUTIONS:
1. When 1 millicurie is used, work behind lead shielding. Handle stock solution vials in
shields or use tongs or forceps.
2. Change gloves often and survey frequently. Smear surveys in uncontrolled areas
required.
3. Segregate wastes to those with half-lives greater than 90 days ( but not with H3 and/or
C14).
4. Dilute aqueous wastes may be disposed to the sewer system in amounts of up to 10 uCi
daily per lab.
6/90

感谢强总！

感谢强总。您这种实事求是的作风令人犹然起敬。

学习下，需要

强老师，版主说的这个问题既然知道叙述矛盾，又没有更改版本也没有声明，怎么三级考试还出这样的试题啊