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24/9/2010 - Radiography overexposure - Finland

This is taken from the IAEA event log.

The Incident - Radiography Overexposure (Finland) (16/09/2010)

(Note: the incident was reported to IAEA 23/09/2010)

 

On September 16, 2010 the radiation safety officer of a licensed industrial radiography company notified the Regulatory Authority of an overexposure of a gammaradiography worker. The worker was exposed by a 0.4 TBq (11 Ci) cobalt-60 source, with the dose exceeding the annual dose limit 50 mSv for radiation workers.

The incident occurred when the radiographer entered the bunker without retracting radiation source to its shielded position. The worker spent about 4 minutes in the bunker while replacing the radiography film. Inadvertent exposure came evident to the worker when he started the next exposure.

Radiographer's personal TL dosemeter was analyzed next day by the dosimetry service and a dose of 58 mSv was reported to the licensee and Regulatory authority.

The incident was a consequence of poor safety culture and maintenance of safety equipment. The radiographer and the area supervisor both realized that the radiation dose rate meter in the radiography site was out of batteries and inoperable, and hence not working. The work was started regardless relying on the alarming personal dose rate meter carried by the radiographer. Also the personal dose rate meter was rendered inoperable by battery failure before the incident, but the radiographer had carried on with the work regardless. These lapses in safety are in direct conflict with regulatory requirements for gammaradiography in Finland.

The exposure would have been avoided had the individual been following written procedures and had properly maintained radiation dose rate meter and a personal radiation alarm.

The event was classified as level 2 on the INES scale.


The incident log can be read at the following link: IAEA News (You may need to log in as a guest).

Ionactive Comment

Well, not a lot to really add here by way of comment - the text above pretty well sums up the situation, the direct cause of the exposure and the lapsed safety practice. I think it is worth adding that this could have been so much worse depending on where the next film was being set up (and therefore how close the individual was from the source).

A 0.4 TBq (11Ci) Co-60 source will created a dose rate of about 125 mSv/h at 1m. This assumes an un-collimated source; if the source was collimated then it might be less by about a factor of 10 out of line of the beam and perhaps half this value within the beam at a distance of 1m. Since this depends on the collimator we can assume it is un-collimated.

The dose he received (58mSv) and the time of exposure (about 4 minutes) suggests a dose rate of near 900 mSv/h. That would imply a distance from the source of < 40cm - this is reasonable given that he was setting up a film - presumably near the previous radiographic shot. He could have been closer if the source was collimated as indicated above.

However, it can be clearly seen that just halving the average distance from source for the same duration (i.e. < 20cm) could have produced an exposure exceeding 200mSv (and of course this heads ever upwards as the source distance is reduce further as described by the inverse square law).

If you follow this blog you will see that this type of accident (actually much more serious) has already occurred this year. Furthermore, there have been a number of incidents over the last few years that appear to show a lack of proper training, supervision and management responsibility with respect to NDT using ionising radiation. This does not say a lot for the NDT industry does it? However, we work with a number of NDT contractors / clients that have an exemplary safety record, well trained operatives and excellent management systems. Therefore this incident is actually NOT typical of the whole industry, which just goes to confirm the need for users of NDT services to ensure their chosen provider meets best practice (i.e. unlike the incident describe above !).

[Edit: two blog posts in two days, what is going on?]

17/9/2010 - Ionactive - so what have we been up to?

Looking backwards, and on to present day

OK, so this may be the longest gap ever between blog posts. It is not that I have given up, far from it, but life has been a bit of a whirl of late and blog updates have just been right near the bottom of the list. Indeed, updates of the website site has fallen short of my normal standards which is a great pity since this site, and our former effort (going back to 2001), came along before the Ionactive consultancy really took off.

During those early days Ionactive (the website) was really known for being a little different from the rest. It was one of the first independent ‘resource' based radiation protection sites that had a commercial wing, rather than a commercial site which had some info simply as a token gesture (i.e. a links page if you were lucky).

We produced a radiation protection glossary, a " It shouldn't happen to a RPA " series and a career (how to be a RPA) series. We were the first to put the elusive (at the time) Radioactive Material Exemption Orders onto the web to save the bother of thumbing through some crumbling paper copy. Indeed the Exemption Order page became so popular that the Environment Agency put a link to it from their intranet (pity we did not get any credit for that!).

Moving forwards we then began to play around with multi-media and commissioned a load of video resource with our good friend Grallator Limited. This resource has proved quite popular both as WMV files on our own site and on the Ionactive Consulting YouTube Channel. Here is an example of the resource that has been produced - one of the best I think.



Moving forwards again we started a blog - something that was designed to be quite informal with a mixture of mostly radiation protection related material, but with the odd article on food (curry!) and progressive rock music. My family has also featured on occasions too.

We have also more recently explored using Twitter and now have an Ionactive Twitter Account, the tweets from which feature on this blog page and on the home page. One Ionactive site victim of Twitter has been our news resource pages which are rather poorly at present having not been updated for some time. However, whilst there is still a lot of triviality on Twitter, and some company intranets ban its use (and even YouTube), we feel this is the best way to get news quickly out to the masses. To get around the Twitter ban we had our webhost write a script to take our tweets and send them to our site via our host and not Twitter direct. This means that even if you cannot get onto Twitter to see what Ionactive is up to, or what is in the news, you can still read the tweets and decide to go and look at the website resource directly.

During all this period (over 10 years) the commercial side of Ionactive has grown and it has become more difficult to populate the site with new material - or indeed write the odd blog entry. These things always happen in phases though and we certainly have not given up providing new resource, it might just take a little longer to produce!

Now for something different.

Diver receives exposure above dose limits

This is taken from the IAEA event log. From time to time we feature these events as they occur, adding our own comments or observations.

The Incident - Exposure of a worker in excess of statutory annual dose limits (31/08/2010)

 

(Switzerland). On 31 August 2010 during the annual refuelling outage of the Leibstadt NPP, a diver was performing maintenance work in the fuel transfer pool within the fuel building. After completion of this work, he recovered an unidentified object and placed it into a transport basket.

While the basket was lifted, before reaching the surface of the water, an alarm of the area radiation monitor was triggered. Therefore, the basket was lowered again.

As a result of the handling of the object, the diver received a hand dose of about 1,000 mSv which is twice the statutory limit of 500 mSv. The diver had worn dosimeters on different parts of the body.


Ionactive Comment


As always we do not have a lot to go on - no other information being available. However this does sound like an avoidable incident - in an environment that one would suppose would be very carefully managed?

Let us assume that the article was handled for 10 seconds before being put into the basket. If that is the case then that would imply a contact dose rate of something like 360 Sv/h - not trivial is it? Assuming that this was held at arm's length in water and let us use Co-60 as the radionuclide for calculation purposes, then it could be that the body dose from this might have been in the region of 100 micro Sv (without water) and perhaps just over 2 micro Sv if you take the water into account.

Of course we are assuming a gamma emitter here, it could have been a pure beta (Sr-90) in which case the betas would have dominated the extremity hazard (with some brem x-rays of course). The brem may have been attenuated in the water at depth but may have been enough to set alarms going as it neared the surface - my bet is still a nasty beta / gamma emitter.

So it looks like this person got away quite lightly with respect to whole body exposure but my hunch is things could have so easily been that much worse.

RPS Training

After a few months of a quiet but steady flow of radiation protection training delegates, our September 2010 course took 25 delegates (we normally limit to 15 but there was such significant demand we organised a larger training room). Out of this total we had three delegates from Qatar Power, and one delegate from Angola (oil industry).

The total mix of delegates was fascinating, covering medical (diagnostic and therapy), security, NORM, process control, education and research. Ionising source use spanned x-ray generators, linear accelerators, a synchrotron, PET radionuclides (F-18), research radionuclides (P-32, S-35, H-3, C-14), process control and NDT radionuclides (Co-60, Kr-85, Ir-192, Se-75) and densitometry measurement (Cs-137 and Am-241/Be).

The mix of delegate types and ionising radiation sources proves to be as popular as ever and shown by some of the latest comments such as:


Eclectic group of delegates which gave a broad insight into radiation and potential risks and challenges within the workplace. Although I have been working with radiation for over 30 years, the course and content kept me attention. Will be sending more of my team on future courses ' (DA, RPS Training, September 2010)


CBRN Radiation Protection Training

I think it is going to be a little quieter on the CBRN radiation protection front as far as the Police and Fire & Rescue Service is concerned. Certainly there is less in the pipeline at the moment and I think it is fairly obvious that with tightened spending budgets there is likely to be less training in the short term.

Radiation & Aviation

I have had a rather interesting aviation / radiation themed existence over the last few weeks / months. More of my personal aviation interests later. Recent client work affirmed the interesting link between ionising radiation / radioactive materials and aviation. For example we have worked on all the following links over recent weeks:

  • Depleted Uranium - Counter weights
  • Thorium - Thoriated jet engine cases
  • Cosmic radiation (a pet interest of mine)
  • Radium - luminescent Ra-226 based paint used in aircraft instrumentation
  • x-rays - the use of x-rays in airport security (including back scatter technology)
  • X-ray XRF (airframe components)


On a diet


Ok, so some of you have heard this before I know. But this is for real ... (I hear you say "Have we not heard that before"!). Seriously, fast approaching that point in my life where I have to make some changes - and health is one of them (for the better). So I am on a goal to get rid of about three stone in total. Apart from generally feeling better (I am already one stone lighter), I need to get through a medical soon (see below). Here I am after some weight loss - the pub background is entirely fake and / or it was my day off (ahem).

Mr Ramsay -  a little lighter!

...and finally - Flying

Mine in on the left!

Having also reached ‘that time in my life' I realise that running Ionactive for some considerable time has been immensely rewarding if not a little stressful (but mostly enjoyable). My time is shared between Ionactive and the family (not always as fairly as I would hope!). However, I wanted something that would be a challenge, would meet my general interests in physics, address a few fears I ‘think' I might have, and generally take me ‘off somewhere for an hour or so'.

My solution might surprise some, including many of my past training delegates who know that I generally cross my fingers when aboard commercial aircraft on my way to clients. Indeed, I do not have a love for heights and during the last holiday with the kids I was stuck at the top of the Windsor Wheel feeling none too pleased, whilst Alex and Ben were beaming from ear to ear with their mum safely on the ground.

Windsor Wheel with Ben - he likes heights, I do not!

So, my choice of flying lessons is one that even a year ago I would not have touched with a barge pole. I am aiming to get a Private Pilots License (PPL) - eventually! That depends on time available and indeed funds available. However, the few lessons I have had to date have been utterly amazing and strangely enough (or perhaps this is not so strange?), I am neither worried about heights nor indeed the flying in general. Even more strange (or perhaps not?), on a recent trip on an Airbus following a lesson, I felt no better. I therefore think being in control is all it takes to remove that anxiety completely. I use ‘control' selectively because Sue my instructor is never far from her set of controls!

Whilst I did not think this flying lark would be easy, it is in fact harder than I thought. It's not the actual control as such - if you break it down into component parts it is not that difficult, but putting it all together and multi-tasking is quite a challenge. There are also 7 ground exams to study for and complete, so that is why I have no illusions that this is a long term project / hobby. As you might note from previous posts, my kids are always getting in on the act, no sooner do I start something they want a go - see what I mean!

Alex and Ben take the controls of the PA28

Furthermore, I am finding I have to recondition my brain into dealing with controls in a way you might not expect if you just casually think about flying. For example, you might consider that the aircraft throttle might be used to make the plane go fast and slow and that the yoke / stick be used to make it go up and down (i.e forwards down, backwards up). In actual fact in a practical sense it is the other way around - you use the throttle to control rate of climb and descent and the yoke / stick to control the airspeed (so in effect you could be going ‘down' with the stick pulled back and with the nose pointing upwards).

This gets even more important if you stall - the nose will dip down quite fast and you need to push forward on the control yoke to un-stall the wings before it will fly again. There goes the ‘PULL UP PULL UP' alarm you might have seen in the movies!

As you know I am interested in novel / different training techniques - I like to think they are an integral part of the Ionactive approach to radiation protection training. Well I have found some excellent resource that has helped explain some of the concepts of flying. Take a look at the following resource which explains the stalling I mentioned above (warning - not PC!).




I think this is an excellent use of multi-media and is quite memorable.

Well enough for now, till the next time. I will leave you with a picture of the flight deck I am learning on (ahem).

Can you guess where they is?!

11/7/2010 - UP UP and Away



OK, so it has been a long time again since the last blog post. Been even busier than before - I will highlight some of the interesting radiation related topics in a later post.

Spent Saturday at the Woodcote Steam Rally near reading. What a fabulous event for all the family - whether you are into steam engines, classic cars, fairground rides, beer festivals or animals there is something for everyone.

I think the highlight for my sons Alex (6) and Ben (3) was a helicopter ride - I was amazed how calm but excited they were about it - handled the event really well with smiles all around. Not sure same could be said for mum watching the three of us take off into the sky - but her smiles returned as soon as we were safely back on the ground!


Here we have Alex and Ben undertaking a few last minute safety checks.




And we are off !




Alex takes the co-pilot position and attends to the navigation:




Ben takes the back seat with Dad - the headphones a tad too big I think!



Amazing trip indeed - all 6 minutes of it!

Oh, and not once did I consider the cosmic radiation dose rate at height - although at 1000-2000 feet I was not going to see much difference from ground level background anyway!

 

2/6/2010 - RPA News, Views, Bays, LNT and Stuff



Work Rate

Not been keeping this blog up to date as much as I would like - it is not that it is a bind or pain, rather it is because I feel quite exhausted much of the time and simply do not have the energy to write. Part of this is to do with the rate of work - it is true that the last 6 months or so have been slower than I would have liked (despite the economy apparently being on the way up), but recently it has gone mad and work has arrived all in one go. Whilst this is welcome it does mean that the weeks / months are now a whirl of travel, assessments, critical examinations, training and similar. Training is really growing and this always takes a lot of preparation time.

I'm not sure if this sudden surge has been caused by clients all deciding they need advice / training at the same time, or if this is indicative of a release of resource after perhaps keeping the belts tightened for the last year or so. Compliance work (i.e statutory Radiation Protection Adviser related) has not relented, but I think discretionary spend (i.e certain training, radiation project related work and similar) has in part taken the back burner.

Indeed, we have slowed the pace of our site radiation protection resource - particularly our radiation protection animations. However, I am pleased to report that things are moving again and we recently released some new ‘linac bunker' related training material (featured below). We have new stuff in the pipeline including industrial radiography bunker animations and some resource on recent industrial radiography accidents (more news about this to be released in this blog soon).

Risk Perception



Regular readers of this resource will know I am quite interested in risk perception - something that is very evident when working with ionising radiation. It has interested me somewhat in the unfolding events regarding volcanic ash. I have had my own travel plans disrupted by ash and have closely followed the media and its reporting style. I recall there have been two specific stages where the allowable concentration of ash has been increased - I believe the current limit is 4mg of ash per cubic metre of air. Whilst there is obvious public concern, I have been interested to observe that there appears to be a general acceptance of these levels by the public - I guess they want to ensure they can still go on their summer holidays!?



The interesting thing to note is their acceptance of the regulatory authorities' view that the level of ash is ‘safe'. I wonder if the same acceptance would be afforded if the nuclear industry were to suggest doubling of their emissions from major establishments (on the basis that the new levels were ‘safe'). I am sure there would be a swift backlash - and I cannot help thinking that this is partly because those that protest are not ‘immediately affected' by the limit rise (unlikely 1000's of holiday makers who are potentially affected by ash concentration limits).

This comparison between ash limits and radiation limits can be extended to consider the ‘science' behind those limits. My understanding is that the ash limits (at the extreme end) are based on ‘deterministic evidence' (i.e. where evidence has shown that certain concentrations have shut down jet engines). At the lower end the limits have been set based on ‘discussions' between airlines and their engine manufactures. There certainly has not been enough time to carry out a rigorous analysis of the ash concentration in order to define a limit that comes under the concept of ‘as low as reasonably achievable'. However, despite rigorous analysis of similar concepts related specifically to ionising radiation exposure, there appears to be no improvement in the general public's view with respect to radiation safety. It seems that volcanic ash will always be more palatable than ionising radiation exposure (despite average natural exposures being significantly larger than average occupational exposures!).

If the Icelandic volcano was to really start spewing its content, I wonder how far ash concentration acceptance would go before the general public said ‘enough was enough'. I believe it might be subject to the concept of Stochastic Effect (and therefore related to an acceptable risk ...). Or ... would it be related to Deterministic Effects and related to a threshold effect (we know that 2000 mg of ash per cubic meter of air WILL stop jet enginers!).

Observations on the Chernobyl Disaster and LNT



On a similar risk theme I came across this paper ‘Observations on the Chernobyl Disaster and LNT' by Zbigniew Jaworowski (Central Laboratory for Radiological Protection - Poland). For those that have a problem with the LNT (linear nonthreshold hypothesis), this paper is a dream and is clearly well written with succinct descriptions of the evidence. The abstract is as follows:

The Chernobyl accident was probably the worst possible catastrophe of a nuclear power station. It was the only such catastrophe since the advent of nuclear power 55 years ago. It resulted in a total meltdown of the reactor core, a vast emission of radionuclides, and early deaths of only 31 persons. Its enormous political, economic, social and psychological impact was mainly due to deeply rooted fear of radiation induced by the linear nonthreshold hypothesis (LNT) assumption. It was a historic event that provided invaluable lessons for nuclear industry and risk philosophy. One of them is demonstration that counted per electricity units produced, early Chernobyl fatalities amounted to 0.86 death/GWe-year), and they were 47 times lower than from hydroelectric stations (~40 deaths/GWe-year). The accident demonstrated that using the LNT assumption as a basis for protection measures and radiation dose limitations was counterproductive, and lead to sufferings and pauperization of millions of inhabitants of contaminated areas. The projections of thousands of late cancer deaths based on LNT, are in conflict with observations that in comparison with general population of Russia, a 15% to 30% deficit of solid cancer mortality was found among the Russian emergency workers, and a 5% deficit solid cancer incidence among the population of most contaminated areas.

The paper can be downloaded from the following link: Chernobyl & LET

(The above link will take you to the main page, to read the paper just enter 'Zbigniew Jaworowski' in the search box and then download the paper for free). 

The paper is hosted by the International Dose-Response Society website - this website deals with hormesis (a dose-response relationship characterized by low-dose stimulation and high-dose inhibition).

I am not an advocate of hormesis in ionising radiation exposure (not enough data) and I do not think LNT can be dismissed out of hand (there is plenty of evidence over many decades to suggest that this relationship is plausible). Furthermore, international recommendations and local legislation applies dose limits that must not be ignored - over time these may be amended but for now they are the law.

Medical Radiotherapy Bay - Training Resource



As noted above we have finally got some of our new linac radiotherapy bay resource released. This resource was originally conceived as part of a bespoke radiation protection course incorporating a shielding design module. What you see below is a 3-d walk through ‘a typical' radiotherapy bay - key features included are the shielding design (primary and secondary), active signage, last person out and confirm buttons, emergency stops and cameras.

To compliment this training we have also included some resource by the OU which shows an actual guided tour though a similar bunker.

 


The OU resource which is clearly related is shown below:



Cosmic Radiation and Se-75

Some of you might think I have a hang-up regarding cosmic radiation since I have written about this on several occasions - I do not. I accept it exists and that the UK Ionising Radiations Regulations 1999 (IRR99) does not include it as an occupational hazard. However, despite using cosmic radiation exposure as a comparator when looking at occupational exposures, there is nothing quite like sitting ‘in it' and taking some measurements to really reinforce the point.

I am aware that the monitors I use are not ideal but it is interesting to note that since I have been taking measurements the values have been consistent across a range of detector types (NaI, ion chamber and GM) - and they are similar to reported values too.



So, I set off yesterday for a 1 hour flight and recorded a peak dose rate of 6 micro Sv/h and 37,000 feet. Taking into account the climb and descent, my EPD accumulated value of 3 micro Sv was about right.

Upon arriving at the client site we rigged up a 10 Ci (370GBq) Se-75 source for some scatter profile measurements for a new open top industrial radiography bay (this bay is massive in plan and 5m high). Part of this process involved ‘stressing the bay' - this is my slang for setting up unusual and rare (and indeed normally non-compliant) situations to provide dose estimates to a critical person outside the bay. Instantaneous dose rates ranged from 1- 10 micro Sv / h (this varied with height and with distance from the bay external shielding wall). At ground level maximum dose rates were 5 micro Sv/h - similar to that experienced at 36,000 (but of much lower energy).

The average length of the shots was 11 seconds - therefore whilst the instantaneous dose rates were higher than background, the value of microSv-in-any-one-hour was much lower. Indeed, at ground level we determined that at full pelt the bay could not be used more than 30 times in any one hour - leading to an accumulated exposure time of about 9% of one hour. Therefore the possible accumulated dose in that hour was 0.45 micro Sv, or about 15% of that received during the one hour flight - this of course can be written as 0.45-microSv-in-any-one-hour. This itself over estimates the exposure by some margin since the instantaneous dose rates described above were worse case rather than those achieved by following best practice.

Explaining these findings to workers on the shop floor who have been watching the measurements needs to be undertaken with care. Using the comparison with flying can be helpful but the ‘unseen' radiation is not always taken as read. Hence the measurements and pictures taken as I fly - showing pictures of instruments in use during a flight, and which can be compared with those used in the bay assessment, can be quite a powerful training tool!

Radioactive Sweets

Oh Yes - fancy Barium Black Cherry, Plutonium Pear, Radium Raspberry Lemonade, Strontium Strawberry, or Uranium Yellowcake? Here they are:



Words fail me - but you can find out more at this link: http://tinyurl.com/2ww8uxg

And finally

My friend outside my office!

 

 

30/5/2010 - Contamination of 6 workers

This is taken from the IAEA event log.

The Incident - Contamination of Six Workers (26/05/2010)

(Note: the incident was reported to IAEA 28/04/2010)

 

(France). Six workers participating in the task of unblocking a high activity radioactive source of cobalt-60 (1.25 TBq) were contaminated in Feursmetal premises (Feurs, Loire). The Co-60 source was blocked since May 7 in the guide tube of a gammagraphy device which was located in a hot cell of the Feursmetal company.

A first recovery operation was carried out unsuccessfully, on 10 May, under the responsibility of Feursmetal and with the assistance of technical teams of the device manufacturer Cegelec. ASN conducted an initial inspection on 12 May to verify the adequate implementation of provisions for radiation protection.

On 26 May, a second operation was carried out by Feursmetal and Cegelec with the support of the French Institute for Radiation Protection and Nuclear Safety (IRSN) which provided specific robots to retrieve and secure the radioactive source. The guide tube section in which the source was blocked had been cut on both sides by the robot but, during this operation, the source was damaged and its content spread. This damage was detected when the robot came out of the hot cell for and triggered the contamination survey.

The 6 workers (2 IRSN, 2 CEGELEC and 2 FEURSMETAL) in charge of the recovery operation were contaminated.

The workers were treated by the specialized medical unit of the EDF St. Albans NPP for proximity reasons and this unit confirmed their internal contamination (anthropogammametry result : contamination between 50kBq and 100kBq). The level of contamination will be specified by the ongoing radio toxicological analysis, after doses reconstructions.

Two inspectors from ASN are on site since May 26 evening.

ASN has provisionally classified this incident at level 2 on the INES scale.


The incident log can be read at the following link: IAEA News (You may need to log in as a guest).

Ionactive Comment

Wow something has really gone wrong with this job. Co-60 sources used in industrial radiography are ‘special form' material which means they are robust in all reasonably foreseeable events (i.e. will not disperse their content).

Co-60 sources will normally be constructed using cobalt metal pellets confined within a welded titanium and stainless steel capsule (probably double or triple welded capsules). Therefore in order to create some level of contamination the robot noted in the above incident report must have chopped the source directly.

Even then, I am surprised that a personal intake of contamination has occurred - even a chopped source would, in my view, result in several mangled pieces and perhaps some level of tiny filings or similar (depending how the cut was made). These would generally be insoluble and not directly respirable - even if taken into the body by ingestion I would probably expect them to go through and out the otherside (where they would of course deliver a local dose on their way).

The actual levels of contamination (kBq range) seem quite modest which is also interesting given the specific activity of the source material (i.e. even a very small piece of source would be expected to be highly active).

As always we have limited information - but the fact that the Co-60 source was catastrophically breached, and that this contamination was transferred to the workers reveals a significant breakdown in work controls and planning.

Also, by my simple calculations, the dose rate from a 1.2 TBq unshielded Co-60 source would be about 368 mSv/h at 1m, dropping to 14.5 mSv/h at 5m. Using 5cm of portable local lead shielding would drop these to 26.5 mSv/h (1m) and about 1mSv/h (5m). OK, so these dose rates are still significant from an occupational worker point of view, but I wonder if working on a larger piece of the guide tube outside the cell would have been better? At least then a cut could be made which would not have damaged the source?!

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This is the company blog of Ionactive Consulting Limited, a Radiation Protection Adviser consultancy. Visit here often to read our views on radiation protection and related matters. You can contact our director and RPA directly at mark.ramsay@ionactive.co.uk

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