Dear Hasna,

correlation is done via the Bragg law:

lambdaCu = 2* dhkl*sin(thetahkl;Cu)

and

lambdaSyn = 2* dhkl*sin(thetahkl;Syn)

for 'Cu as source' the Cu k-alpha radiation is used: lambdaCu = 1,5406A;

for the synchrotron based XRD please use the x-ray  wavelength lambdaSyn, which was set up by the monochromator for these scans.

The positions thetahkl (2thetahkl) of the XRD peaks at the theta (2theta) axis are scaled by the wavelength in use.

In "traditional" XRD using a Cu(Kalpha) source, the diffraction pattern gives the position of the diffraction peaks as a function of teta (or 2 teta), whereas when using synchrotron radiation the diffraction pattern gives the position of the diffraction peaks as a function of energy.

In both cases, the interplanar distance (d) is given by Bragg's law, as Dr. Martens explains; however, it must be adequately written:

For "traditional" XRD: 2*d*sin teta (variable)= lambda (fixed)

For synchrotron XRD: 2*d.sin teta (fixed) = lambda (variable)

as E(keV)= 12.4/lambda (Å), then

2*d.sin teta (fixed) = lambda (variable)= 12.4/E or

E*d*sin teta (fixed)=6.2 which is more frequently used.

As the value of "d" is the same in both equations, then:

lamba (fixed)/2*sin teta (variable) = 6.2/E*sin teta (fixed) or

E = 12.4* sin teta (variable) / lambda (fixed) * sin teta (fixed)

So you can transform the diffraction pattern from one technique to another.

Best regards,

Pedro

Thank you all.

P. Grima Gallardo Hi, Gallardo. so if i want to convert the synchrotron XRD data into conventional XRD (Cu K) data, what should i do? is there any suggestion? thank you.

It is very easy. You must adapt Bragg equation 2d sin(theta) = lambda for each experiment since for traditional XRD measurements lambda is fixed, whereas for synchrotron lambda is variable:

Traditional XRD: 2d sin (theta variable)=lambda (fixed) or 2d=lambda (fixed)/sin (teta variable)

Synchrotron: 2d sin (teta fixed) = lamda (variable) or 2d=lamda (variable)/sin (teta fixed). As the term 2d is identical for both expression, then:

lambda (fixed)/sin (theta variable)=lamda (variable)/sin (teta fixed)

If you have synchrotron data:

sin (theta variable)= lambda fixed/lamda (variable)/sin (teta fixed)

Lambda fixed and sin (theta fixed) are parameters of the experiment whereas lambda variable is obtained from E (variable) using the expression E(keV)=12398/lambda(Å).

P. Grima Gallardo Dear Gallardo, this really helps. And have successfully done it in highscore plus. Thank you.

Thank you, Yongtie. If you like my answer please don´t forget to recommend.

P. Grima Gallardo @ Sir, you are talking about synchrotron XRD data colleceted in energy dispersive mode. If we fix the wavelength, then we can collect XRD pattern with theta as variable (Bragg's law)

P. Grima Gallardo Dear professor:

I use the method, our experiment parameter is E=15 keV， lamda (variable) =0.82656 (Å)

while I convert the data to Cu K (1.5418 Å ) have some problem

(1.5418 Å/0.82656 Å )=fixed

theta1 is the data from synchrotron

theta2 is the purpose Cu K data

sin(theta2) = fixed * sin(theta1)

while I implement operator in arcsin( fixed * sin(theta1)) to obtain the data, the fixed * sin(theta1) may upper than 1 that are not in arcsin() domain

which parameter need to be corrected

thank you very much

Dear Lee Wei Jin ,

there is no need for a correction of any parameter. Your equation is right.

According to the wavelength in use you cannot map the whole wave length range of theta1 into theta2 when lamda2/lambda1= fixed >1 .

The restriction is:

sin(theta2 )= lamda2/lambda1*sin(theta1)= fixed * sin(theta1)

Dear Lee Wei Jin ,

just an amendment.

Another, closely related restriction arises also from the Bragg equation:

only a restricted range of wavelengths/photon energies can be used for given lattice plane distances dhkl:

lambda/(2*dhkl) =sin (thetahkl) < 1 *)

*) just a re-written from of the Bragg equation

Dear Professor Gerhard Martens ,

Thanks for your enthusiasm and explanation

let me know more about XRD data processing.

this greatly help to me

Thank you.

P. Grima Gallardo

is that possible to change traditional XRD data to Synchrotron