Thank you @Vladimir Dusevich, @Alan F Rawle.

I think BSE is good method if there are only two elements present in the alloy system. Since Be percentage is quite low, through the contrast in images qualitative information can be obtained.

As far as ESCA/XPS is concerned, since Be sensitivity is low (4 Be 1s 0.059), i think it is difficult to obtain its spectrum in presence of Copper (and oxides).

If it's only Be and Cu, then quantify the Cu, say, by a wet chemical route, and estimate the Be by difference.

Please find attached a ppt file which describes analytical methods applicable for Be. ICP-MS seems to be the most sensitive:

https://www.aiha.org/aihce07/handouts/rt251ashley.pdf

Thank you @Alan F Rawle and @Gyorgy Banhegyi.

However,

I want to know about any instrument/spectroscopic technique which can distinguish Be element on the copper surface without degrading the CuBe component.

I don't want to weigh the total Be content in the CuBe component. I just need to differentiate Cu and Be on the surface itself.

It should be similar like EDS where at any point on the surface itself we can show elemental spectrum.

(Unfortunately EDS doesn't resolve the elements having low At. no. )

If Be concentrated in some second phase in Cu matrices, you can use BSE signal in SEM. BSE by itself cannot identify elements, but it can nicely highlight phases with lower mean atomic number. with pretty good resolution.

OK, so now the rules of the game change....So go for ESCA/XPS (or Auger) for the surface itself remembering that the top 5 - 10 ionic layers will be fully oxidized and there'll be preferential concentration of one of the elements at the surface due to chemisorption induced segregation.  Do we now require the bulk composition?  OK, then argon ion etch the top layers. Note: XPS detects all elements with an atomic number (Z) of 3 (lithium) and above....

Well depending on the ability of the alloy to dissolve, spectrophotometric determination of beryllium using the Chrome Azurol S as reagents. Other reagents are also available.

Spectrophotometric determination of beryllium in bronzes with chrome azurol S

Eskinja, I.; Grabaric, Z.; Grabaric, B.S.

Mikrochimica Acta; ISSN 0026-3672; Worldcat; CODEN MIACA; v. 2(5-6); p. 443-450

Thank you @Vladimir Dusevich, @Alan F Rawle.

I think BSE is good method if there are only two elements present in the alloy system. Since Be percentage is quite low, through the contrast in images qualitative information can be obtained.

As far as ESCA/XPS is concerned, since Be sensitivity is low (4 Be 1s 0.059), i think it is difficult to obtain its spectrum in presence of Copper (and oxides).

Hi

Try to use the wavelength dispersive spectroscopy (WDS).   The WDS is known technique   for chemical analysis of elements with 6 or less atomic number.   Therefore, a combination of the back scattering electron (BSE) imaging , as Vladimir has suggested, and the WDS could work to not only image the Be-Cu compound by the BSE but also it can quantify  the Be in the Be-Cu compound by the WDS. 

you can think about XPS or LIBS (laser induced breakdown spectroscopy)