Check Source | Automess


Check source 6706

Check source 6706 with lead container 6706-1, nuclide Cs-137, activity 333 kBq ±10%, version in accordance with (currently withdrawn) DIN 44427. The Check source requires a handling permit because its activity is above the 10 kBq exemption limit.

The Check source together with the respective emitter holder is suitable for many of our devices to extend the calibration period.

Why an activity of 333 kBq? This is historically justified in the German Radiation Protection Ordinance (StrlSchV) from 1965. It states that the exemption limit for Cs-137 is 10 µCi (370 kBq). In order to stay below this exemption limit and because the activity of the test source is tolerated at 10%, the nominal activity was long ago set to 90% of the exemption limit of 10 µCi at the time, i.e. 9 µCi or 333 kBq (mathematically correct one would actually have had that activity set to 370 kBq/1.1 = 336 kBq, but there is still a small additional safety distance of 3 kBq).

Check source 6707

Check source 6707 with stainless steel container 811.1, nuclide Cs-137, nominal activity 333 kBq ± 10%. The Check source requires a handling permit because its activity is above the 10 kBq exemption limit.

This Check source is only designed and suitable for checking the Szintomat 6134A(/H). It has the shape of a cylinder, the round end faces of which each have a collar with which the Check source can be placed on the 6134A(/H) instead of the protective cap. One of these faces is made of grey material, and the other is black like the body of the cylinder. The radioactive preparation is located inside the cylinder directly behind the centre of the black face. The distance of the preparation from the scintillator therefore depends on the orientation in which the Check source is placed. As a result, the 6134A(/H) can be exposed to two well-defined dose rates, which differ by a factor of 10 (7 µSv/h and 0.07 mSv/h). For the old 6134A, this Check source is approved to extend the validity period.

Nuclide and activity (Cs-137 and 333 kBq) are the same as for type 6706, so what has been said for type 6706 applies to the use of the Check source.

Check source 6708

Check source 6708 with alpha and beta radiation, 1 kBq Am-241 + 2 kBq Sr-90, activity tolerance each ±30%. Particularly suitable for control measurements on the contamination detection probes 6150AD-k and 6150AD-17. The total activity is below the exemption limit (10 kBq for both Am-241 and Sr-90), which makes handling much easier.

Instructions for handling, especially for transport

When dealing with Check sources, certain requirements of the Radiation Protection Ordinance (StrlSchV) must be observed, please see the data sheet on this.

Even if you have purchased a test source according to an older StrlSchV, new obligations may arise from the StrlSchV from 2001, in particular the leak test, see the information sheet on this.

The dispatch of Check sources can be a dangerous goods transport. If you have no experience with the transport of dangerous goods, we strongly recommend that you commission a suitable forwarding agent to do this. Even then, as the shipper, you are not yet released from obligation because you are responsible for packaging and the accompanying documents. For this purpose, we would like to send you some carefully compiled but non-binding information that is restricted to our Check sources, which we have taken from the following regulations: The ADR is a European agreement on the international carriage of dangerous goods by road and the RID is a regulation on the international carriage of dangerous goods by rail. In the case of air freight, the IATA (International Air Transport Association) dangerous goods regulations apply. These regulations contain exemption limits for the total activity per shipment. If these exemption limits are not exceeded, they are not radioactive substances within the meaning of the regulations and are therefore not dangerous goods. The exemption limits of the nuclides occurring in our Check sources are:

Instructions for handling, especially for transport
Nuklid Last revised 2013: Exemption limit according to StrlSchV, ADR and IATA
Cs-137 10 kBq
Sr-90 10 kBq
Am-241 10 kBq

The fact that the exemption limits are identical according to all three regulations StrlSchV, ADR and IATA is certainly no coincidence, but it does not change the fact that each of these regulations defines the exemption limits themselves. If these exemption limits are exceeded, but do not exceed certain multiples (“A1/A2 levels”) of the exemption limits, shipping can be carried out as an “exempted package” (designation according to ADR) or “excepted package” (designation according to IATA). Such an excepted package contains dangerous goods that are so well packaged that they are relatively safe to transport. Despite the confusing term “excepted”, they are still dangerous goods!

The transportation of excepted packages is simplified in accordance with ADR/IATA and does not require approval in accordance with section 17 (1) number 2 of the StrlSchV. ADR and IATA make certain almost identical claims to an excepted package.

According to this, our Check sources, if their activity is at all above the exemption limit, can be transported as “UN2910 radioactive substances, excepted package – limited amount of substance” (to exceed the “A1/A2 levels”, one would need hundreds or even thousands of Check sources) . In addition to the limited quantity, there are some other requirements for the exempted package:

  • The dose rate must not exceed 5 µSv/h at any point on the outer surface of an excepted package. To do this, it can make sense to place a physically small radioactive substance in the middle of a larger box. For the Check source 6706, we recommend packaging it in such a way that each outside of the lead container is at least 5 cm away from the outside of the packaging. Doing so meets this requirement with a clear safety margin.
  • Under routine conditions, the package keeps the radioactive content enclosed and the inside of the package is labelled “RADIOACTIVE” in such a way that when the package is opened there is a visible warning of the presence of radioactive substances.
  • The package must meet the general requirements for safe packaging.
  • However, there are no special building, testing or approval regulations for the packaging of excepted packages.
  • The non-adherent contamination on the outside of a package must be as low as possible and must not exceed the following limits under routine transport conditions:
    4 Bq/cm² for beta or gamma emitters as well as low-toxicity alpha emitters
    0.4 Bq/cm² for all other alpha emitters
    As our Check sources 6706 and 6707 are leakproof, they cannot lead to contamination, neither of the package nor at all, as long as they are not damaged.
  • Each shipping item is clearly legible on the outside and permanently marked with an identification of the sender and the recipient.
  • Each free shipping item is clearly legible and permanently marked on the outside with the four-digit UN number, which is preceded by the letters “UN”, in our case with “UN2910”. The official name of this UN number, namely “radioactive substances, limited amount of substance”, is not required on the outside of excepted packages. If the package is repackaged, the outer packaging must also carry this label.
  • All (external) markings must
    a) be clearly visible and legible,
    b) withstand the weather without significantly impairing its effectiveness,
    c) IATA only: present themselves with colour contrast to the background; To do this, the “UN2910” marking must have red and white diagonal hatching on the edge. Of course, it is convenient to also use such particularly easily recognisable stickers for shipments sent other than by air freight

The following information is required in the documentation (accompanying documents):

  • Number and description of the packages, as well as the total quantity of the dangerous substances as gross or net mass (e.g. 1 box, total gross mass 3 kg) per UN number
  • Name and address of sender and recipient.
    However, you should not enter this remark if you have the dangerous goods transported by third parties and do not know what else this third party carries in your vehicle. Only the third party can know whether the exemption limits set out in subsection ADR have been exceeded and must then act accordingly.

The following additional information in the accompanying documents (not on the outside of the packaging) is not required for excepted shipping items, but is also not harmful:

  • The number of the class of the dangerous goods, that is 7.
  • Name or symbol of each radionuclide (e.g. Cs-137).
  • A description of the physical or chemical form (e.g. test emitter 6706).
  • The maximum activity (e.g. 370 kBq).
  • Reference to measures that may have to be taken by the carrier (e.g. “No special measures are required for loading, stowing, transport, handling and unloading.”).

You can find a proposal for a blank accompanying document with the minimum requirements here. You can find an example of the accompanying paper we use with details that go beyond the target here.

If a shipment contains radioactive material below the exemption limit, this could lead to unjustified commotion if the shipment is checked during transportation. To avoid this, the ADR expressly permits the inclusion of a corresponding declaration in the transport documents, e.g. “NO CLASS 7 GOODS”. This enables the sender to make it clear that they are not radioactive substances within the meaning of the ADR. An example of the explanation we use for this purpose can be found here.

Other countries, other customs...

As discussed above, there are some international similarities with regard to the exemption limits. Of course, there are also national particularities. Let’s take Switzerland as an example. Switzerland is not a member of the EU, but it has close economic ties with the EU. Nevertheless, other exemption limits apply in Switzerland (called authorisation limits there):

Nuklid Exemption limits from 96/29/EURATOM and its successors 2013/59/EURATOM Licensing limits of the Swiss Radiation Protection Ordinance, as of 1 January 2012
Cs-137 10 kBq 700 kBq
Sr-90 10 kBq 60 kBq
Am-241 10 kBq 0,2 kBq

Surprisingly, this means that our Check sources in Switzerland are classified in exactly the opposite way to those in the EU:

Check source Within the scope of 96/29/EURATOM or its successor 2013/59/EURATOM In Switzerland
6706, 6707 registration required free
6708 free subject to approval due to Am-241

There are probably many more examples to be found. However, we do not wish to attempt to compare all countries in the world with regard to their exemption limits. We just want to remind you that despite all “globalisation” nobody is spared having to worry about regulations in their own country.

Check source with other radionuclides?

Of course, it would be desirable to use Check sources whose activity is below the exemption limit. Then Cs-137 fails as a candidate because 10 kBq is not sufficient to cause a sufficiently large display on the measuring device. Alternatives are Ba-133 (HWZ 10.5 years) and Eu-152 (HWZ 13.5 years).

For both of these nuclides, the exemption limit according to StrlSchV and ADR is 1 MBq (as of 2010). From a technical point of view, Eu-152 is more suitable (larger HWZ, larger average photon energy). With 1 MBq Eu-152, you would have a rather powerful test emitter that generates a dose rate of slightly more than 17 µSv/h at a distance of 10 cm. Without shielding in a small package, this test emitter would not even meet the requirements for an excepted package, even though it is not a dangerous good because it does not exceed the exemption limit. This sounds a bit contradictory. In 2006 we examined the possibility of using Eu-152 instead of Cs-137 and sent the result of our considerations to our supervisory authority with a request for comment. Unfortunately, our supervisory authority has not made a binding statement on this. So it cannot be ruled out that handling below the exemption limit is not quite as free (think, for example, of the general principle of dose reduction from Section 6 of the StrlSchV). Under these circumstances, we decided not to switch to another radionuclide because this change would have required a great deal of organizational effort (addendums to all PTB-approved control devices), which would then have been unsuccessful in the end.

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