Akshata Pattanshetti

Open, dead pores adsorb nitrogen in a porous material. Closed pores do not adsorb nitrogen. Your device measures adsorption by reducing dead pore volume. You need to set the adsorption start point correctly.

It is unusual for there to be no measurement points because of failure to reach equilibrium. Very often this failure would come from leaks of gas or of air.

Do the samples show forever increasing or decreasing adsorption, or cell pressure, in the trend data ?

Do you hear the valves opening and closing continuously, while the instrument tries to obtain the target pressures ?

Are you sure there is no problem with the o-rings which you are using for the cells, and that the outgassing of the samples is good?

It might be useful to discuss with your supervisor or the owner of the instrument about using the very good "SystemCheck" maintenance function of the BELSORP software. This performs a "Health check" of many of the functions of the instrument.

First you must verify the pressures of the Helium and Nitrogen supplies to the instrument, then the SystemCheck procedure can be started. There are instructions in the manual. Follow the instructions given on the screen.

If there is any leak, or other problem with the instrument, then this function will normally show it in the file that is created - it may be called "Operation test" for your BELSORP-mini-II. Depending on what it indicates, maybe some intervention or cleaning is necessary. If there are no problems found, then maybe try a measurement with empty cell, and/or with a reference sample.