Re: chirper

[Ted de Castro <tdc@XRAYTED.COM>]

Respectfully - I think you have it backwards.  We are not looking for a

"blue light special" - we are looking for a cost effective device that

does what we need for safety and not a lot of what we don't need - or

can do without if it means affording fewer of these devices.  Being cost

effective is no crime!



In any event - in your example below - the person works in the 20 mR/hr

field for 25 minutes and never has any indication at all that he was in

any sort of field at all.  IF he had been there for 30 minutes - or

moved closer to hit the 30 mR/hr alarm point THEN - AFTER having gotten

to those levels he would know.  This says working in 20 mR/hr for 25

minutes and getting 8.3 mR is OK - that is NOT ALARA.



The chirper on the other hand would let him know he is in a field the

WHOLE time he is in the field BEFORE he gets to 10 mR or 30 mR/hr.  This

gives him the opportunity to adjust his position or time to lessen the

chirp rate or total accumulated exposure - THIS is ALARA.



I work in an area where waiting until 10 mR is too late.  In all cases

there are near background areas very close by and no NEED to work in a

field of even a few mR/hr - IFF you know the field is there.  Since

these fields are transitory - knowing they are there as SOON as they are

encountered is the key to ALARA.



William V Lipton wrote:

> 

> I'll need some help in understanding your statement that, "The

> alarming device is after the fact.  The chirper is an ongoing monitor

> that is on the radiographer..."

> 

> If the dose rate from the shielded source is 20 mR/hr, and I set the

> alarming ratemeter to alarm on 30 mR/hr OR 10 mR integrated dose, it

> seems that, assuming the ratemeter is working and worn properly and

> the person responds properly to the alarm, this WILL prevent an

> overexposure.  It will also tell me if the radiographer is not

> practicing ALARA in handling the source, even if he does not receive

> an overexposure.

> 

> Chirpers are ok; alarming ratemeters are :  (1) a lot better, and (2)

> required by the NRC.

> 

> So let's stop looking for the Blue Light Special on chirpers, and talk

> about how we can get the regulators and licensees to take radiography

> hp seriously.

> 

> The opinions expressed are strictly mine.

> It's not about dose, it's about trust.

> Curies forever.

> 

> Bill Lipton

> liptonw@dteenergy.com

> 

> 

> AndrewsJP@AOL.COM wrote:

> 

> > I...

> >

> > All these devices will not do what a chirper will do, and that is

> > prevent an overexposure.  The alarming device is after the fact.

> > The chirper is an ongoing monitor that is on the radiographer.

> 

> ...

> 

> > John Andrews

> > Knoxville, Tennessee

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