## 3 Results and Discussion
### Test of Self-Made Cell with Reduced Background  
With the previous observation that the background coming from the small-angle scattering of the sample might play a role and that also the side of the transmitted beam might influence a proper data evaluation, a new GISANS cell design with minimized material around the sample was tested. PNIPAM microgels adsorbed on Si-block were used as a test sample.  
Figure 4 shows a photograph of the self-made quartz cell (a), its components (b) and the principal beam path for reflection and transmission. Basically, a quartz glass backplate was placed on a frame with boron containing glass for neutron absorption, both were directly glued together with the Si-block which contained at its surface the sample (PNIPAM-microgel particles). Small gaps on one side with syringe needles allowed us to fill the cell with water. The borated glass was used to reduce possible scattering by the glue at the interface between the glass layers. What is the optimum condition and material in this respect has to be studied in more detail in the future. D\({}_{2}\)O was used to increase scattering contrast to the PNIPAM microgels and avoid high incoherent contribution as could be in case of H\({}_{2}\)O.  
This cell design with its minimum surrounding opens the new possibility of measuring the dynamics of polymer systems in grazing incidence geometry by means of grazing incidence neutron spin echo spectroscopy (GINSES). Due to the instrumental setup of neutron spin echo spectrometer and very limited area for the in- and out-path for the beam usually used in an aluminium cell, currently GINSES can only be measured off-specular in \(q_{z}\) direction at \(q_{y}\)=0. With proposed cell design it would be possible to rotate the sample cell for a scan in the direction of \(q_{y}\), giving access to lateral dynamics along the interface.  
The first GISANS experiment with the proposed cell is presented in Figure 5. The left side of the detector image contained the part with the reflected beam and the GISANS scattering. On the right side of the detector (within green frame) the transmitted beam was visible. The line cut along the \(q_{z}\) direction at \(q_{y}\) = 0 is presented on the right side of Figure 5.  
Figure 4: Cell design with minimum amount of auxiliary material. (**a**) shows a photograph of the cell, the assembly is presented in (**b**). The beam path for reflected and transmitted beam is shown in (**c**).  
The line cuts of the data obtained with our cell with minimal material (black line) were compared to that of the often used design with aluminum front- and back-plates with water channels for thermalization (red line). On the transmission side, additionally the radially averaged SANS intensity of this side of the detector is presented (blue dots) with a fit of the data (cyan) with an Ornstein-Zernike model for thermal fluctuations [13, 42].  
A significantly reduced background could be achieved with the proposed new design, which was necessary for the low-intensity GISANS experiments with biological or soft matter systems and allowed us to focus only on the scattering of the desired parts of the sample.  
The self-made cell had the advantage that only a minimum amount of cell material was required, with the disadvantage that the temperature control was not possible with such a cell in the usual way done with Al cell and had to be provided by other means. For example, a thermalized air jet in the sample area, as it is used also for other \"conventional\" experiments, e.g., in Ref. [43] for the thermal control of an in-situ DLS setup.