AARCH is a network which involves several laboratories throughout Europe that have the same aim to measure the Earth’s magnetic field in the past as it is revealed by archaeological material and contribute this way to the rescue of cultural heritage.

However, to obtain this aim through a fruitful  collaboration  of  all the network laboratories, it  is  important  that  all  of  them  “speak”  the  same language! Often, the wide range of equipment and software used by  each  laboratory,  the differences on measurement procedures  or  units  used,  make it difficult  to compare the results obtained. For this reason AARCH  team  has  started  an  inter-laboratory  calibration check, involving all the AARCH member laboratories.


Phase 1 - measurement equipment           Report available
In October 2003,  the  AARCH  team  at  Torino oversampled a Roman kiln at Canosa (southern Italy) in order  to  provide specimens  for an inter-laboratory  instrument  check.   Five cylindric specimens of standard  size  were  prepared  from  five  independently oriented bricks. The specimens were  first  measured  at  the  palaeomagnetic laboratory of the University of Torino several times in a time period  of  a month in order to check for any significant viscous magnetization  acquired. Afterwards,  the  specimens  were  sent  to  the  other  laboratories  to  be measured. Each  laboratory  was  asked  to  measure inclination, declination and intensity of the natural remanent magnetisation (NRM) and  the  magnetic  low-field susceptibility at  low frequency.

Up to now, replies  have  been  received  from  9  of  the  12  AARCH laboratories and a first discussion of the results was already made  at  the AARCH workshop 2 at Thessaloniki, in April 2004.  In  most  cases  magnetic susceptibility and  intensity  results  show  a  good  agreement  among  the different laboratories, but as far as  the  inclination and declination  results  are  concerned,  some  small discrepancies have been pointed out. Their significance  should  be  further examined when all the laboratories will  have  measured  the  specimens  and when the samples will have been remeasured at laboratory of Torino. A final discussion and interpretation of the results is planned for the AARCH workshop 3 in Madrid (March 2005).

Download the inter-laboratory calibration report phase 1 as pdf-file.

For further information contact Evdokia Tema: evdokia.tema@unito.it



Phase 2 - data analysis                               New !  Report available  New!
The second phase of the interlaboratory calibration concerns the analysis of demagnetisation data. The AARCH team at Madrid provided two data sets of thermally and of alternating field demagnetised samples from two archaeological sites. Each laboratory is asked to calculate the mean direction of both sites. The outcome has been discussed at the AARCH workshop 3 in Madrid (March 2005).

Download the inter-laboratory calibration report phase 2 as pdf-file.

For further information contact Gregg McIntosh or Gianluca Catanzariti:  gregc@fis.ucm.es, gcatanza@fis.ucm.es