Weblims     OWA     Home     Contact Us    

Actlabs
Back to Home


21 of 150    Prev    Next     

1D & 1D Enh - INAA

Determining rock types, alteration patterns and levels of pathfinder elements are key for the geologist to assess exploration potential. Actlabs’ "Au+34" (Code 1D) is a cost effective multi-element approach to Au, PGE and base metal exploration.  Code 1D Enhanced with enhanced detection limits is also available.

INAA (Instrumental Neutron Activation Analysis) is an analytical technique dependent on measuring gamma radiation induced in the sample by irradiation with neutrons. The primary source of neutrons for irradiation is usually a nuclear reactor. Each activated element emits a "fingerprint" of gamma radiation which can be measured and quantified. Routine multi-element analyses by INAA are performed on practically any material from the smallest sample which can be weighed accurately to very large samples.

The sample is encapsulated in a polyethylene vial and irradiated with flux wires, standards and blanks at a thermal neutron flux of 7 x 10 12 n.cm-2 s-1.The samples are measured the next day for the induced Au-198 photopeak at 411.8 KeV. Samples are compared to a calibration developed from multiple international reference materials. 

 

A 30 g aliquot, if available, is encapsulated in a polyethylene vial and irradiated along with flux wires at a thermal neutron flux of 7 x 10 12 ncm-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. Duplicates are analyzed when samples are provided.

Code 1D (Au+34)  Elements and Detection Limits (ppm)

Element

Detection Limit

Upper

Limit

 

Element

Detection Limit

Upper Limit

 

Element

Detection Limit

Upper Limit

Ag

5

100,000

 

Hf

1

500

 

Se

5

10,000

As

2

10,000

 

Hg

1

1,000

 

Sm

0.1

10,000

Au

5 ppb

30,000 ppb

 

Ir

5 ppb

10,000 ppb

 

Sn

0.05%

10%

Ba

100

500,000

 

La

1

10,000

 

Sr

0.1%

40%

Br

1

1,000

 

Lu

0.05

1,000

 

Ta

1

10,000

Ca

1%

50%

 

Mo

5

10,000

 

Tb

0.5

1,000

Ce

3

10,000

 

Na

0.05%

10%

 

Th

0.5

10,000

Co

5

5,000

 

Nd

5

10,000

 

U

0.5

10,000

Cr

10

100,000

 

Ni

50

10,000

 

W

4

10,000

Cs

2

10,000

 

Rb

30

10,000

 

Yb

0.2

1,000

Eu

0.2

2,000

 

Sb

0.2

10,000

 

Zn

50

100,000

Fe

0.02%

75%

 

Sc

0.1

200

 


Code 1D Enhanced (Au+34) Elements and Detection Limits (ppm)

Element

Detection Limit

Upper

Limit

 

Element

Detection Limit

Upper Limit

 

Element

Detection Limit

Upper Limit

Ag

5

100,000

 

Hf

1

500

 

Se

3

10,000

As

0.5

10,000

 

Hg

1

1,000

 

Sm

0.1

10,000

Au

2 ppb

30,000 ppb

 

Ir

5 ppb

10,000 ppb

 

Sn

0.02%

10%

Ba

50

500,000

 

La

0.5

10,000

 

Sr

0.05%

40%

Br

0.5

1,000

 

Lu

0.05

1,000

 

Ta

0.5

10,000

Ca

1%

50%

 

Mo

1

10,000

 

Tb

0.5

1000

Ce

3

10,000

 

Na

0.01%

10%

 

Th

0.2

10,000

Co

1

5,000

 

Nd

5

10,000

 

U

0.5

10,000

Cr

5

100,000

 

Ni

20

10,000

 

W

1

10,000

Cs

1

10,000

 

Rb

15

10,000

 

Yb

0.2

1,000

Eu

0.2

2,000

 

Sb

0.1

10,000

 

Zn

50

100,000

Fe

0.01%

75%

 

Sc

0.1

200

 

 

 

 

 

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
Search | Privacy | Contact Us | News RSS | Login