X radial machine exposure parameter calculation method

X radial machine exposure parameter calculation method

Fundamental parameter determined

一、base on penetrated thickness:single wall single image=T;double walls single image or double walls double images=2T

1、≤10mm，1mm is equal to 5KV

2、10~20mm,1mm equal to 6.2KV

3、21~30mm,1mm equal to 9KV

4、31~40mm,1mm equal to 12KV

二、focal length

Each time focal length increases or decreases 100mm,voltage will increase or decrease 10KV.

三、time 

1minute =25KV

X ray machine exposure parameter is (base number);penetrated thickness T=8mm,voltage is 170KV,time is 1minute。

四、the distance of focal point to window of X ray

XXQ 2005 120 mm

XXQ 2505 150 mm

XXQ 3005 170 mm

五、calculating methods

1、when penetrated thickness increases or decreases 1mm,the voltage change is performed on basis of (一)

2、when focal length increases or decreases 100mm,the voltage change is performed on basis of (一)

3、each time the time increases or decreases 1 minute,voltage increases or decreases 25KV

For example: calculating exposure of φ219*14 pipe welded junction

The First step:make sure the type of X ray ,XXQ 2505 or XXQ3005 type;

The Second step:calculating focal length219+150=369 or 219+170=389mm

The Third step: confirm focal length and voltage variable quantity,we usually think X ray exposure normal base number as standard,namely 600mm； φ219*14 focal length is 219+150=369mm or 219+170=389mm,compare to base number ,it shorten 231mm or 211mm,then the voltage should decrease 23KV or 21.1KV。

The Forth step:when calculate penetrated thickness change,voltage variable quantity, our basic thickness is 8mm, now the penetrated thickness is 14*2=28mm。Thus this is more 20mm than basic number is 8mm,on the basis of 4 in (一) ，the compensation dosage is :20mm*8KV=160KV,because the basic number is170KV,so normal exposure parameter is 170KV+160KV-23.1KV=306.9KV or 170KV+160KV-21.1KV=308.9KV,the time is 1minute。

The Fifth step :Due to 1minute=25KV,on the basis of this ,calculating XXQ 2505 or XXQ 3005 type exposure parameter:

1、XXQ 2505：using 240KV ,its time is (306.9KV-240KV)/25KV/minute=2.68 minutes;the 2.68 minutes is need to compensate for 2.68 minutes on the basis of original 1 minute,therefore basic 1minute should be added, namely it is normal exposure time is 2.68 minutes +1minute ≈4minutes 

2、the same,XXQ3005 type:using 280KV, its time is (308.9kv-280kv)/25kv/minute=1.2minute;the 2.68 minutes is need compensate 1.2 minutes on the basis of original 1 minute,namely it is exposure time is 1.2minutes +1minute≈2.5minutes.