# Glossar

All · A · C · D · E · F · G · L · M · N · P · S · T · W · Z

# S

## Scintillator

A scintillator consists of a transparent material (liquid, plastics or crystal) where special substances are incorporated which emit a scintillation light flash if their atoms are excited by ionizing particles.
The transparency enables to guide the light to a photo sensor (PMT or MPPC) connected to the scintillator. More details can be found in the Wikipedia article.

The CosMO detectors consist of a plastics scintillator plate (20cm x 20cm x 1cm) where 9 fibers of 1mm diameter glued into the plate guide the light flash to the 3mm x 3mm surface of the multi pixel photon counter (MPPC).
The muon detectors at the “Polarstern”, the Neumayer III station and the Trigger Hodoscope use plastics scintillator plates (25cm x 25cm x 1.5cm) with 8 fibers of 1.5mm diameter which were originally produced for the L3-Cosmic experiment at CERN.
The LIDO experiment uses 12 liters of a liquid scintillator (EJ-321L, Eljen Technology). The main component is petroleum oil with additions of aromatic hydrocarbons and other components to produce the scintillation light.

## Silicon Photomultiplier

The Silicon photomultiplier (SiPM) is a solid-state photomultiplier which has several advantages compared to normal PMTs as small size, robustness and much lower input power (70-100 V). A disadvantage is the temperature dependence of the output signal. Therefore, long-term measurements with SiPMs should be performed at stable temperature.
Details on SiPMs are given in the Wikipedia article. The SiPM used in the CosMO detectors has a sensitive surface of 3 mm x 3 mm. It is produced by Hamamatsu and called Multi-Pixel Photon Counter (MPPC, product type S10362-33-50C).

## Sine and Cosine Functions

The trigonometric functions sine and cosine and their squares describe mainly periodic processes or the dependence of a physical quantity on the angle. The general form of the sine function is: $f\left(x\right)=a\cdot \mathrm{sin}\left(bx+c\right)+d$
$a$ - stretch/ compression along the y-axis
$b$ - stretch/ compression along the x-axis. This parameter can be determined from the period $T$: $b=\frac{2\pi }{T}$
$c$ - shift along the x-axis. For a shift in positive x-direction, c is negative, for a shift in negative direction, c is positive.
$d$ - shift along the y-axis.

For example, the cosine2 function can be used to describe the zenith angle dependence of the muon flux with the CosMO mill. In Cosmic@Web, a fit function can be inserted directly into the corresponding diagram. The notation in the online analysis tool is as follows: p[0]+p[1]*cos(p[2]*x/180*pi)**2
Where **2 stands for the power. For example, x2 is represented as x**2.

The parameters p[0], p[1] and p[2] refer to the following properties:
p[0] - minimum of distribution
p[1] - maximum of distribution
p[2] - phase