Assuming you have refined your standart using NPR=7 (TCH function)

1) open a new text file

2) copy the following lines (it's the irf file of one of our diffractometers):

! Resolution Function : 1

! To be used with IRESO=1 in FullProf.2k (version > 1.6)

! 2theta-min step 2theta-max

THRG 2.0 0.01 160.00

! Lambda1 Lambda2 Ratio(I2/I1)

WAVE 1.54056 1.54056 1.0

! NPROF Shape1 Shape2 Shape3

PROF 7 0.0 0.0 0.0

! S_L D_L

ASYM 0.01800 0.0180

! Uins Vins Wins Xins Yins Zins

0.005786 -0.003284 0.002932 0.012747 0.00000 0.00000

3) change the differents values of the parameters depending of the conditions acquisition (lambda, 2Theta-min, ...), and the refined parameters of your standart (U,V,W,X,Y,Z) 

4) save the file and change the Filename extension as "irf" 

best wishes,

 Thank you Dr. Lefeve for your details elaboration.

I have no Idea about standart, i am afraid. I refined my samples with Pseudo-Voigt function. Please let me know what are required to do micro structure analysis using Fullprof.  

Both diffractometer and sample contribute to the broadening of the peaks. In fact the observed profile is a convolution of the diffractometer contribution and the sample one. Therefore if you want to study micro-structure of the sample, you have to do correction of the instrumental contribution. that can be done using a standart (e.g. Al2O3, LaB6, ...) for which the refined parameters are encompassed in the irf file. Fullprof uses then this file to do the correction.

Dear

Dr. Lefevre,

I have XRD data of Al2O3. Now my task to refine Al2O3 usingTCH function and replace the parameter as you instructed?

Exactly.

1) Refine the standart which will give you the instrumental contribution

2) change the parameters in the irf file with respect those you have refined

3) You can refine the sample. In fullprof (still with TCH function) :

    a) select your irf file

    b) fix U,V,W = 0 and just refine Y (size) and X (strain)

    c) after refinement, Fullprof will create a mic file in which all information dealing with microstructure are encompassed.

best wishes,

Dr. Lefevre,

Your instructions are very helpful, very straight and easy to understand. You save my time. Many Many Thanks.

Dear Dr. Lefevre,

Sir, can I use this above irf file (what you have given) for Npr=5 ? If not then, what can I do? ....I think not...(I am beginner.)

When? I should use irf file.

Dear Krishna,

The IRF file contains parameters that account for the contribution of a diffractometer to the observed peak shape. Different instrument will contribute differently to the profile shape, hence it is recommended that you investigate the contribution of your instrument. You will have to find out the values for your instrument by running a full range for LaB6 (SRM 660). You can then deduce the IRF parameters by plotting FWHM^2 against Theta. From which you can use Caglioti's formula ( FWHM^2 = U tan^2 θ + V tan θ + W ) to deduce your IRF parameters - U, V and W.

Thanks Bidemi Fashina. It really helped a lot.

Dear Christophe Lefevre,

How do I get the values of S_L and D_L belonging to ASYM from Rietveld refinement on the XRD pattern of standard sample?

Thank you