Sigma 130Ci 관리 매뉴얼

1.3

At 1m per Ci (37GBq)

At 1ft per Ci (37GBq)

Ytterbium-169

0.125R/hr

1.25mSv/hr

1.3R/hr/Ci

13.0mSv/hr

Selenium-75

0.203R/hr

2.03mSv/hr

2.2R/hr/Ci

22.0mSv/hr

Iridium-192

0.48R/hr

4.80mSv/hr

5.2R/hr/Ci

52.0mSv/hr

Cobalt-60

1.30R/hr

13.0mSv/hr

14.0R/hr/Ci 140mSv/hr

Selected attenuation data
Material

Approximate

Approximate half value thickness

material

inches(mm)

density

Ytterbium-169

Selenium-75

Iridium-192

Cobalt-60

Concrete

2.35g/cm

3

1.140 (29.0)

1.180 (30.0)

1.700 (43.2)

2.400 (61.0)

Aluminum 2.65g/cm

3

–

1.100 (27.0)

–

–

Steel

7.80g/cm

3

0.170 (4.3)

0.315 (8.0)

0.512 (13.0)

0.827 (21.0)

Lead

11.34g/cm

3

0.047 (1.2)

0.039 (1.0)

0.200 (5.1)

0.500 (12.7)

Tungsten

17.80g/cm

3

–

0.032 (0.8)

0.130 (3.3)

0.310 (7.9)

DU

18.70g/cm

3

–

–

0.050 (1.3)

0.270 (6.8)

Operating distance
The distance between the remote control and the exposure head is determined by summing

the length of the remote control conduits plus the total length of source guide tubes used,

and normally should not exceed 47ft (14.2m).
Standard remote controls:

25ft (7.6m), 35ft (10.7m), 50ft (15m).
Standard source guide tubes (projection sheaths):

7ft (2.1m) set of three source guide tubes: 21ft total (6.3m).
NOTE
The total length of source guide tubes utilized must be shorter in length than the remote

controls to ensure the source assembly will project into the working position.
e.g. When using 25ft (7.6m) remote controls, a maximum of three

7ft (2.1m) source guide tubes can be used with a combined length of 21ft (6.4m).
Conversely, when using 35ft (10.7m) remote controls, a maximum of four

7ft (2.1m) source guide tubes can be utilized.
When using 50ft (15m) remote controls, a maximum of six 7ft (2.1m) source guide

tubes can be utilized. This limitation is due to the weight and friction of remote control

cable length.