Right and my understanding is that the soft x-rays are more harmful than the hard ones, so I've heard.
Bev

-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Guy Ramsey
Sent: September 6, 2019 6:26 PM
To: [log in to unmask]
Subject: Re: [TN] XRAY inspection of SMT

The filter absorbs low energy that does nothing for the image, but would otherwise be absorbed by your product.

On Fri, Sep 6, 2019 at 5:22 PM Wayne Thayer <[log in to unmask]> wrote:

> What's the difference between a filter and just dropping the power?
>
> On Fri, Sep 6, 2019 at 12:39 PM Bev Christian 
> <[log in to unmask]
> >
> wrote:
>
> > TechNetters,
> > Guy nailed it when he mentioned "Zn filter".  We (BlackBerry) just 
> > used commercial grade Al foil and that seemed to do the trick.  With 
> > regards
> to
> > 2D/3D, I would think if your 3D machine is fast enough this 
> > shouldn't be
> a
> > problem (with filter).  Comments?
> >
> > Regards,
> > Bev
> >
> > -----Original Message-----
> > From: TechNet <[log in to unmask]> On Behalf Of Guy Ramsey
> > Sent: Friday, September 6, 2019 3:24 PM
> > To: [log in to unmask]
> > Subject: Re: [TN] XRAY inspection of SMT
> >
> > We had a great discussion on this topic last year. In response we 
> > purchased a gross of little dosimeters from Landauer, and 
> > characterized
> our
> > 3D AXI.
> > The results were truly horrifying.
> > We shared our results with the manufacturer. Characterized their new 
> > machine and decided 3D AXI was not for us. We traded the machine for 
> > two upgraded AOI machines.
> > Then we evaluated x-ray equipment with new knowledge. Added a zinc 
> > filter and now do 2D x-ray at a safe and reasonable dose.
> >
> > On Fri, Sep 6, 2019 at 3:07 PM Wayne Thayer <[log in to unmask]>
> > wrote:
> >
> > > I thought you guys would get a kick out of something Analog 
> > > Devices just sent me when asked about a voltage reference chip 
> > > apparently damaged by XRAY inspection:
> > >
> > > "Given all the variables that can affect device performance, 
> > > Analog Devices, Inc. does not recommend subjecting non-radiation 
> > > hardened or tolerant devices to radiation exposure beyond normal 
> > > background
> > radiation.
> > > "
> > >
> > >
> > > Brilliant, huh? Don't XRAY ANY ADI parts unless they are the tiny 
> > > subset of the radiation hardened line!
> > >
> > > My expectation is that they would give a dosage range. Silly me....
> > >
> > > Wayne Thayer
> > >
> >
>