How can I properly attribute unpublished data gathered by someone else when using it in my masters thesis? I am currently writing my master's thesis. The project is a cooperation of the lab of my university supervisor, where I am writing the thesis, and a research institute, where I am employed part-time as a research assistant.
My thesis work involves analyzing measurements that were taken from someone else who is affiliated with the research institute. The measurements are not part of a public dataset and, as far as I know, will not be published. The data is not being reused from previous work, but was measured for this project.
I want to explicitly state in my thesis that taking these measurements are not part of my thesis, but I am unsure how to do this properly. Throughout the majority of my work, the data is used, so I would like to avoid mentioning its origin each time. It would of course make sense for me to acknowledge the contribution of the person who conducted the measurements, but I do not think this is sufficient.
The reason I am asking about this is that in order to submit my thesis, I am required to sign a form stating 'I am the sole author of this document and did everything myself, unless stated otherwise', which I believe is quite common. For other documents, a citation would be appropriate. However, I believe this case is different because there is no formal document accompanying the dataset.

How can I sufficiently state that the data used throughout my thesis was not measured by me, and at which point in the thesis should I do so?
Is it sufficient to mention the origin of data once, such as in the introduction?
Should I write a section (perhaps in the appendix) where the measurements are described in detail, including who conducted them?


Related Questions:

How to write the data section when data is reused from a previous work? (different, because it is about re-using data from a previous paper of the same author)
How to use data from a colleague who retired in my thesis without commiting fraud or plagiarism (The person who gathered the data is suggested as a co-author, which is not allowed for my master thesis)
In my opinion, stating in the introduction &quot;the data were taken in the such and such experiment prepared and run by A.Becede&quot; would be enough. It's not unusual to analyse data from someone else's experiments, especially at MSc level.
Just as a tip, in my field when we cite something unpublished, we cite it as:
&quot;A.Becede - private communication&quot;
or
&quot;courtesy of A.Becede&quot;.