where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -
1055 views
Technical Discussions
T.J.J.K
T.J.J.K
05:38 Sep-27-2008
Ionization by Radiography

When radiation penetrates a material , depending on energy of radiation electrons are being ejected (Compton,Pairproduction& Photoelectric effect ).

Is this loss a permanent loss & if permanant does the loss of electrons leads to Ionization.

If Ionization happens how does the atom regain the electrons.
( The main process by which the Film is exposed is ejection electron by the radiation as it passes through the lead intensification screen, Does this lead to Ionization of the Intensification screens , Is this Ionization permanent or does it happen?)


    
 
 Reply 
 
N.Kuppusamy
Consultant, NDT Level-III Engineer
Advanced Inspection & Testing (S) Pte Ltd, Singapore, Joined Dec 2003, 34

N.Kuppusamy

Consultant, NDT Level-III Engineer
Advanced Inspection & Testing (S) Pte Ltd,
Singapore,
Joined Dec 2003
34
02:37 Sep-28-2008
Re: Ionization by Radiography
Electron loss in the material is not permanent. It immediately acquired the required electrons from the atmosphere and neighboring atom. The atmosphere replenish their lost ions from cosmic radiation.

The lead screen also replenish their electron from atmosphere when the radiant source is removed. This is called reversible reaction.

But the films made of photosensitive chemicals and they undergo photochemical reaction when exposed to photons (electromagnetic radiation).

When a film is exposed, the Silver from Silver Bromide emulsion is reduced to metallic Silver and Bromine remains in electronegative state (actually the AgBr molecule become polarized to Ag+ and Br- . This photochemical reaction is irreversible and cannot replenish its electron deficiency from atmosphere.

The development process reduces the delta Ag+ to metallic Ag and forms the latent image of the object radiographed. This latent image is fixed and unwanted Br- is removed in the fixer solution.

I learn these details 25 years before in my Level-II course.

Now I wonder how the new generation practitioners lacking this fundamental knowledge even after 25 years of advancement in technology.

Regards,
N.Kuppusamy




    
 
 Reply 
 
chris s
Consultant, qc manager
USA, Joined Apr 2007, 9

chris s

Consultant, qc manager
USA,
Joined Apr 2007
9
07:40 Sep-29-2008
Re: Ionization by Radiography
----------- Start Original Message -----------
: Electron loss in the material is not permanent. It immediately acquired the required electrons from the atmosphere and neighboring atom. The atmosphere replenish their lost ions from cosmic radiation.
: The lead screen also replenish their electron from atmosphere when the radiant source is removed. This is called reversible reaction.
: But the films made of photosensitive chemicals and they undergo photochemical reaction when exposed to photons (electromagnetic radiation).
: When a film is exposed, the Silver from Silver Bromide emulsion is reduced to metallic Silver and Bromine remains in electronegative state (actually the AgBr molecule become polarized to Ag+ and Br- . This photochemical reaction is irreversible and cannot replenish its electron deficiency from atmosphere.
: The development process reduces the delta Ag+ to metallic Ag and forms the latent image of the object radiographed. This latent image is fixed and unwanted Br- is removed in the fixer solution.
: I learn these details 25 years before in my Level-II course.
: Now I wonder how the new generation practitioners lacking this fundamental knowledge even after 25 years of advancement in technology.
: Regards,
: N.Kuppusamy
------------ End Original Message ------------

Everyone has to start somewhere. Not everyone is as endowed as you sir.


    
 
 Reply 
 
Nick Welland
Other, Quality and NDT
Aben Technical Services, Australia, Joined Oct 1999, 42

Nick Welland

Other, Quality and NDT
Aben Technical Services,
Australia,
Joined Oct 1999
42
09:34 Oct-01-2008
Re: Ionization by Radiography
----------- Start Original Message -----------
: : Electron loss in the material is not permanent. It immediately acquired the required electrons from the atmosphere and neighboring atom. The atmosphere replenish their lost ions from cosmic radiation.
: : The lead screen also replenish their electron from atmosphere when the radiant source is removed. This is called reversible reaction.
: : But the films made of photosensitive chemicals and they undergo photochemical reaction when exposed to photons (electromagnetic radiation).
: : When a film is exposed, the Silver from Silver Bromide emulsion is reduced to metallic Silver and Bromine remains in electronegative state (actually the AgBr molecule become polarized to Ag+ and Br- . This photochemical reaction is irreversible and cannot replenish its electron deficiency from atmosphere.
: : The development process reduces the delta Ag+ to metallic Ag and forms the latent image of the object radiographed. This latent image is fixed and unwanted Br- is removed in the fixer solution.
: : I learn these details 25 years before in my Level-II course.
: : Now I wonder how the new generation practitioners lacking this fundamental knowledge even after 25 years of advancement in technology.
: : Regards,
: : N.Kuppusamy
: Everyone has to start somewhere. Not everyone is as endowed as you sir.
------------ End Original Message ------------

Knowledge is not endowed, it is worked for. The loss of fundamental knowledge is not restricted to our own field; stories abound that some first-year university students are functionally illiterate, which news I find frightening.
I ascribe much of the decline to the philosophy of "teaching to the exam" where the object is to gain a qualification rather than knowledge per se.
We "stand on the shoulders of giants", but it behoves us to ensure that a cadre is educated to carry on!
Regards,
NW


    
 
 Reply 
 

Product Spotlight

Magnetic X-Ray Pipeline Crawler

Zhong Yi brand pipeline crawler is magnetic/micro-video controlled crawler with DC X ray unit inst
...
alled for checking welding of pipeline. Move steadily inside the pipeline 6''-60''diameter with speed of up to 18m/min, Max. moving diatance 5 kilometers and provide the efficient inspection of the pipeline.
>

ISONIC 3510

Very Powerful Superior Performance Extremely Portable Smart Phased Array Ultrasonic Flaw Detector an
...
d Recorder with 2 Conventional UT and TOFD Channels uniquely combines PA, single- and multi-channel conventional UT, and TOFD modalities providing 100% raw data recording and imaging. Suitable for all kinds of every-day ultrasonic inspections
>

Aerospace Systems - Automated Ultrasonic Inspection

USL are specialists in the design and manufacture of turnkey ultrasonic inspection systems for aer
...
ospace applications. From monolithic composites to complex honeycomb structures. This video shows just a few examples of what is possible, find out more at: www.ultrasonic-sciences.co.uk
>

MUSE Mobile Ultrasonic Equipment

The MUSE, a portable ultrasonic imaging system, was developed for in-field inspections of light-weig
...
ht structures. The MUSE consists of a motor-driven manipulator, a water circulation system for the acoustic coupling and a portable ultrasonic flaw detector (USPC 3010). The MUSE provides images of internal defects (A-, B-,C- and D-scan).
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window