"Part II Paper" accepted (July 2005)

 

The paper "First international 26Al interlaboratory comparison - Part II" submitted for publication in Nucl. Instr. and Meth. in Phys. Res. B by S. Merchel and W. Bremser is accepted (239/3 (2005) 217-226).
online-publication (only abstract)


 

Request for results Part III (Meteorites by AMS) (March 2004)

 

Dear colleagues,

about 2 years ago, you received four samples for processing as a participant in Part II/III of the Al-26 interlaboratory comparison.

From what we learned about the organization of Part I, we decided not to ask for results every three months. We hope that this has given every participant a very reasonable time to process and measure samples and we hope that we will have results from everyone soon and we can complete the comparison. So, we kindly ask you to submit results on samples M1, M2, M3, and M4 as soon as possible.

During Part II/III of the investigation, we wish to examine the possibility that chemical processing of samples will influence results. To accomplish this, we will attempt to exclude possible errors resulting from primary sources. Therefore, everybody is asked to normalize their results to a common "standard material" and "half-life". This does not mean that we want to specify which reference material or half-life of Al-26 you should use for any future measurements; however, for this study, we must be able to use the same values to exclude errors resulting from these sources. Because everyone measured Sample B from Part I, we asked you to normalize your ratios to this sample with the value (1.350 ± 0.023) E-11 26Al/27Al. For conversation from ratio to dpm/kg-data use the half-life value of 7.05 E5 years.

Please send us as much information as possible about the chemical processing of the samples. We designed an EXCEL-Spreadsheet as a guideline for the minimum information we would like to receive. Please feel free to submit any additional information (e.g. references). If enough laboratories submit results on other radionuclides, e,g 10Be, we might ask you to send further information on these analyses later. Of course, your anonymity will again be ensured.

We hope that this part of the comparison will be - thanks to your hard work - as successful and helpful for quality assurance in the AMS community as Part I (the Part I paper has been accepted by NIMB and, therefore, can be cited in any future publications).

Thanks and best regards from Berlin, Silke Merchel


 

"Part I Paper" accepted (January 2004)

 

The paper "First international 26Al interlaboratory comparison - Part I" presented at AMS-9 and submitted for publication in Nucl. Instr. and Meth. in Phys. Res. B (Proceedings of AMS-9) by S. Merchel and W. Bremser is accepted (223-224 (2004) 393-400).
online-publication (only abstract)


 

Status Report Part III (Meteorites by AMS) (August 2003)

 

Samples were submitted to the chemistry labs in February 2002.

The labs were asked to report Al-26 activities in units of dpm/(kg meteorite).
For better comparison the results should be

  • normalized to the average ratio of Sample B of Part I: (1.350 +- 0.023) x 10 -11

  • converted from ratios to activities by using a half-life of 0.705 My.

Any further details of the applied processing, e.g. description of applied chemistry (carrier, determination of natural Al content etc.) should be reported together with results.

Chemistry and AMS measurements are still running.


 

Final results Part II (Meteorites by counting) (August 2003)

   

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Final results Part I (Al2O3) (May 2002)

   

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Sample submission Part II (Meteorites) (February 2002)

 

Dear colleagues,

finally the last sample of part II of the Al-26 interlaboratory comparison made it back to me. After the first announcement in which I informed the AMS community about this part (almost three years ago), I am able to submit the four processing samples.

This (un?)expected delay was mainly due to technical and personal problems at the counting labs, but we had also one late drop out. Fortunately, we could compensate this by three new labs well known in the metrology business (EC-JRC, Institute for Reference Materials and Measurements (IRMM) in Belgium; Physikalisch-Technische-Bundesanstalt (PTB) and the Nuclear Engineering and Analytics Rossendorf Inc (VKTA) in Germany), but this also took some extra time.

Samples

These are four meteorite samples containing natural contents of Al-26. For those who are not familiar with meteorites: The expected activities are 20-140 dpm/kg (stony meteorites) and 1-4 dpm/kg for the iron meteorite (sample M2), respectively. The samples are either crushed or metal cut. But be careful, in contrast to the first part of the comparison, these samples shall nearly represent “real processing samples“ incorporating possible real inhomogeneity. So please, take all steps you usually apply to an inhomogeneous sample!

As you can imagine, it was not easy to get “enough“ meteorite material from the curators. The amount I could split to everybody is (at least):

M1 - 350 mg
M2 - 2 g
M3 - 450 mg
M4 - 500 mg

In case of “emergency“ you might apply for another portion of a sample, but from my personal experience it should be possible to do at least (!) 2 chemical separation experiments with this amount.

Results

It would be helpful if you submit (as soon as possible) a date at which you expect to measure the samples. If there is a delay, no problem, just brief me.

As results of your measurements you are asked to report Al-26 activities in units of dpm/(kg meteorite). I also ask for any further details of the applied processing, e.g. description of applied chemistry (carrier, determination of natural Al content etc.)

Other nuclides?

For not “wasting“ any material, my suggestion is that you also try to measure the other long-lived radionuclides (measurable by AMS) separable from this material, too. Please, reply if and in which nuclides you might be interested in. I guess the favourable ones will be Be-10 and Cl-36.

We may be able to recruit some additional participants (any suggestions from you?) if we include other nuclides. But this would be of course an additional task. The main task will still be Al-26, but I would rather like to collect as much data we can get from this precious material!

Concluding remarks

As most of you already know I moved from MPI Mainz to the Federal Institute for Materials Research and Testing (BAM) in Berlin in late 2000. Therefore, the website had to move, too. The URL is now: http://home.t-online.de/home/silke.merchel/26al.htm. There you will find anytime any new information (including this letter).

Please confirm the receipt of the samples. Good luck to everybody! Have fun and best regards,

Silke Merchel


 

First results Part I (Al2O3)  (May 2001)

   

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The document is password protected !

You will get the password after submitting your own results.

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Sample submission Part I (Al2O3) (July 2000)

 

Dear participants of the Al-26 interlaboratory comparison,

it’s your turn, now. Attached you will find 4 Al2O3 samples each weighing at least 10 mg. The expected 26Al/27Al ratios are of the following orders:

Sample A - 1E-10

Sample B - 1E-11

Sample C - 1E-11

Sample D - 5E-13

Please confirm the receipt of the samples and let me know when I might expect your results. Of course, I hope to get the data as soon as possible, but as a deadline I would like to set the end of this year. If you should need more time for the measurements, please let me know and I will see what we might do about it.

Just to remember: These samples belong to the first part of the comparison. The four meteoritic samples of the second part will be send to the chemistry labs as soon as the counting labs will have finished their measurements.

Best regards and thanks again for your contribution in this project

Silke Merchel


 

Second status report (June 2000)

 

Due to some technical problems of the counting labs they are still busy with the measurements of the samples. Therefore and because some of the AMS labs are not interested in the second part of the interlab comparison (the meteoritic samples), we decided to split up also in time. You will get the artificial Al2O3 samples of the first part in July and the meteoritic samples of the second part as soon as the counting labs have finished their measurements (December 2000 ?).

I will submit about 10 mg Al2O3 of each sample. If you need more material, please let me know as soon as possible. You will, of course, get information on the expected order of the ratios for the individual samples (not the exact value!) together with the samples. This information will also be available here on the web.

I hope that we can finish the first part of the comparison before the end of this year. If you have any problems with this deadline, please let me know as soon as possible, too.

Thanks again for joining the comparison.

Silke Merchel


 

First status report (March 2000)

 

At the moment the counting labs are busy with the measurement of the samples. Because high activities are needed to get good statistics we cannot split the samples. Since two additional counting labs have joined the comparison, we are delayed in submitting the samples to the AMS labs. But I think it is worthwhile to wait to get additional numbers. As soon as the counting labs have finished their measurements, the AMS and chemistry labs will receive aliquots of the samples.

Here is some additional information on how the comparison will work for the AMS labs:

There are two independent parts of the comparison.
It is your choice to join both or just the first one:

  • In the first part you will get 4 Al2O3 samples with different 26Al/27Al ratios.
    As results of your measurements you are asked to report these ratios.

  • In the second part you will get 4 meteorite samples.
    Each laboratory is responsible for its own chemical preparation of these samples.
    As results of your measurements you are asked to report 26Al activities in units
    of dpm/(kg meteorite).

If you want to join the second part and do not know how to do it yourself, you can choose:
Either you get in contact with one of the participating chemistry labs and ask them for a co-operation or you try do the chemical separation of aluminium out of the meteorite on your own.
In the latter case I can provide you with some helpful information.

This is important:
Due to my role as the “independent organiser” of this comparison, I cannot help you to do the chemical separation in practice!

Thanks again for joining the comparison.

Silke Merchel


 

First announcement

 

Dear colleagues,

as you have probably heard already some AMS labs recently found out that there are some discrepancies in the 26Al data among different labs. Therefore, we decided to initiate an interlaboratory comparison.

For this purpose we invite you to participate in this project. This comparison will however be of value only if most of the AMS labs working with 26Al will take part in the exercise. So, please help to improve the quality of data of the whole 26Al community. Needless to say, we will guarantee the personal anonymity by using codes for the participating laboratories.

Here are the details. We will have a suite of 8 samples to measure: 4 synthetic standard type materials (Al2O3) and 4 processing samples (meteorites). Each of the latter ones will be analyzed in advance by six counting laboratories. All AMS laboratories will be responsible for their own chemical processing of these samples. If there is more than one chemistry laboratory involved preparing samples for your AMS facility who wants to take part in the comparison we can submit additional processing samples. Please fill in the application form and send it back to me as soon as possible. Electronic submission is also possible.

Looking forward to hearing from you and best regards, 

Silke Merchel


Preliminary list of participants

 

Counting labs  
 

   

Dirk Arnold
Physikalisch Technische Bundesanstalt, Braunschweig
dirk.arnold@ptb.de

Giuseppe Bonino
Dipartimento di Fisica Generale, Torino
cane@ph.unito.it

Ulrich Herpers
Nuklearchemie, Köln
ulrich.herpers@uni-koeln.de

Gerd Heusser
MPI Heidelberg
Gerd.Heusser@mpi-hd.mpg.de

Mikael Hult
EC-JRC, IRMM, Radionuclides Metrology, Geel
mikael.hult@cec.eu.int

Matthias Köhler
VKTA Rossendorf e.V.
matthias.koehler@vkta.de

John F. Wacker
Pacific Northwest National Laboratory, Richland
john.wacker@pnl.gov

       
   

AMS labs

 
 

     
Marc Caffee
PRIMELab
mcaffee@physics.purdue.edu

L. Keith Fifield
ANU Canberra
lkf103@nucvs7.anu.edu.au

David Fink
AMS-ANTARES
fink@ansto.gov.au

Koichi Kobayash,Hiroyuki MATSUZAKI
Micro Analysis Laboratory, Tandem Accelerator [MALT], Tokyo
hmatsu@malt.rcnst.u-tokyo.ac.jp

Peter W. Kubik
ETH Hönggerberg, Zürich
kubik@particle.phys.ethz.ch

Florian Kubo
TU München  (Part I only)
fkubo@ph.tum.de

Toni Wallner, Alfred Priller
VERA-Laboratory, Wien
alfred.priller@univie.ac.at

Albert Zondervan
Institute of Geological & Nuclear Sciences (GNS), Lower Hutt
A.Zondervan@gns.cri.nz

   

Chemistry labs
(if different from AMS)

 
 

     
Elisabetta Boaretto / Aaron Kaufman
Weizmann Institute of Science, Rehovot
elisa@wis.weizmann.ac.il

Mike Bourgeois
PRIMELab
bourgeois@primelab.physics.purdue.edu

Ulrich Herpers
Nuklearchemie, Köln
ulrich.herpers@uni-koeln.de

Greg Herzog
Rutgers University
herzog@rutchem.rutgers.edu

Hisao Nagai
Nihon University, Tokyo 
hnagai@chs.nihon-u.ac.jp

       
   

AMS labs
 "who will measure
samples in the future"

 
 

     
Elisabetta Boaretto / Michael Paul
Weizmann Institute of Science, Rehovot
elisa@wis.weizmann.ac.il

Klaas van der Borg
Robert J. van de Graaf Laboratorium, Utrecht
K.vanderBorg@phys.uu.nl

Jorge Fernandéz-Niello
TANDAR Lab, Buenos Aires
fniello@tandar.cner.gov.ar

Bob Finkel
CAMS, Lawrence Livermore National Laboratory
finkel1@llnl.gov

Douglas J. Donahue
Tucson
DJD@physics.arizona.edu

Ragnar Hellborg
Lund
ragnar.hellborg@nuclear.lu.se

Göran Possnert
Ångstrom Laboratory, Uppsala
Goran.Possnert@Material.uu.se


 

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Last modified 20.04.2008

   

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