[ RadSafe ] Baggage Inspection X-ray Systems
mark.ramsay at ionactive.co.uk
Mon Jul 31 23:27:46 CDT 2006
Morning from the UK
It depends to some extent where you are in the world with respect to the standards.
In the US you have the US standard 1020:40 - Performance Standards for Cabinet X-ray Systems. These can be found at the following link.
You will note these are quite old (revised 2005) but are still valid. For example they state that the exposure at 5cm from any surface will be less than 5 microSv/h (Apprx conversion). They also include very direct instruction like, for example, 'The insertion of any part of the human body through any port into the primary beam shall not be possible.'
If you are in the UK (as I am). Then we turn to the Ionising Radiations Regulations 1999 (IRR99). In many ways this is far less prescriptive then the US standard - more 'goal setting' one might say. However its clear in Regulation 8 (Restriction of Exposure) and Regulation 31 (Duties of Manufactures, suppliers etc...) that exposures must be ALARP (as low as Reasonably Practicable). Furthermore, since one does not want to operate the equipment in a Supervised or Controlled Area then there are some specific exposure limits to be employed.
A guide to the UK legislation can be found on our site at the link below:
IRR99 does allow for a 'Generic Authorisation' for x-ray equipment but this does not apply directly to x-ray systems used for security scanning. However the basic info contained in the GA and in Regulation 8 is what we (in the UK) apply to x-ray screening equipment when we carry out a critical examination (under Regulation 31). For example one performance standard would be:
1) provide safety devices, as referred to in 1(a), which for routine operations should be configured so that the control system will ensure that an exposure:
(a) cannot commence while any relevant access door, access hatch, cover or appropriate barrier is open, or safety device is triggered;
(b) is interrupted if the access door, access hatch, cover or barrier is opened; and
(c) does not re-commence on the mere act of closing a door, access hatch, cover or barrier; or
With respect to exposure on the outside of the enclosure we would work to a limit of 1 microSv/h. Note this is from a dose rate that is 'averaged at a point over a minute'. Dose rate is an important defined term since it is true that the instantaneous dose rate at a point near the curtain will be higher than this value as the baggage goes through.
We can also turn to the EU Directives such as the Euratom Basic Safety Standard (Council Directive 96/29/Euratom). A link to this can be found below:
There is nothing very specific in the above legislation but the principles are still valid.
Hope this has been of some use.
Mark Ramsay MSc, MSRP
Radiation Protection Adviser
IonActive Consulting Ltd
mark.ramsay at ionactive.co.uk <mailto:mark.ramsay at ionactive.co.uk>
07841 435377 (mobile)
0871 7333945 (fax)
IonActive Consulting Ltd
7 Farmers End
From: radsafe-bounces at radlab.nl on behalf of Borisky, Michael (Civ, ARL/ADLO)
Sent: Mon 31/07/2006 18:45
To: radsafe at radlab.nl
Subject: [ RadSafe ] Baggage Inspection X-ray Systems
Can someone direct me to the standard that specifies the Health Physics
requirements for baggage inspection X-ray systems like RAPISCAN,
DYNASCAN, etc, that use a belt to carry the item to be inspected through
an X-ray inspection area? I'm most interested in seeing what leakage
monitoring and interlock/warning system testing and inspection
requirements are specified. Thanks!
ARL Radiation Safety
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