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4A - Research - INAA

A 1 g aliquot is encapsulated in a polyethylene vial and irradiated with flux wires and an internal standard (1 for 11 samples) at a thermal neutron flux of 7 x 1012 n cm-2 s-1.  After a 7-day period, to allow Na-24 to decay, the samples are counted on a high purity Ge detector with resolution of better than 1.7 KeV for the 1332 KeV Co-60 photopeak. Using the flux wires, the decay-corrected activities are compared to a calibration developed from multiple certified international reference materials. The standard present is only a check on accuracy and is not used for calibration purposes. From 10-30 % of the samples are rechecked by re-measurement.  For values exceeding the upper limits, assays are recommended.

One standard is run for every 11 samples. One blank is analyzed per work order. Selected duplicates are analyzed when enough material is submitted.    

Code 4A RES/MS is also available; elements are determined by fusion ICP/MS.

 

 

Code 4A-Research Elements and Detection Limits (ppm)

Element

Detection Limit

Upper Limit

Element

Detection Limit

Upper Limit

Element

Detection Limit

Upper Limit

Ag

2

10,000

Fe

0.01%

-

Sc

0.01

-

As

1

-

Hf

0.2

-

Se

0.5

-

Au

2 ppb

30,000 ppb

Ir

2 ppb

-

Sm

0.01

10,000

Ba

20

100,000

La

0.05

10,000

Sr

100

-

Br

0.5

5000

Lu

0.01

-

Ta

0.3

10,000

Ca

0.2%

-

Mo

2

10,000

Tb

0.1

Ce

1

10,000

Na

0.001%

10%

Th

0.1

10,000

Co

0.1

10,000

Nd

1

10,000

U

0.1

10,000

Cr

0.5

100,000

Ni

50

10,000

W

1

10,000

Cs

0.2

-

Rb

10

Yb

0.05

-

Eu

0.05

1000

Sb

0.1

10,000

Zn

10

 

 

Code 4A RES/MS Elements and Detection Limits (ppm)

Element

Detection Limit

Upper Limit

Pr

0.01

1,000

Gd

0.01

1,000

Dy

0.01

1,000

Ho

0.01

1,000

Er

0.01

1,000

Tm

0.01

1,000

 

Note:    
 Assays are recommended for values which exceed the upper limits.

 

Reference :
Hoffman, E.L., 1992. Instrumental Neutron Activation in Geoanalysis. Journal of Geochemical Exploration, volume 44, pp. 297-319.

 


Activation Laboratories Ltd. | 41 Bittern Street, Ancaster, Ontario, L9G 4V5, Canada | TF: +1.888.228.5227
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