GRIFFIN User's Web Toolkit
This web-based toolkit will provide useful applets to assist GRIFFIN users with planning, performing and analyzing GRIFFIN experiments.
The webpage is mirrored in two locations:
Guelph URL here
This page can be used to determine the expected detector efficiency for a particular gamma ray of interest.
Origin of the Data
The data used in this applet are Geant4 simulations of the detector performance in the geometry of the GRIFFIN spectrometer. The simulations were computed using Geant4.9.6.p02 on Scientific Linux 5.8 (32-bit architecture). These simulation results were produced in October 2013 and have not been experimentally verified at this stage.
The user can select the configuration of GRIFFIN for the setup they want to use. GRIFFIN consists of 16 HPGe clover detectors but not all detectors may be present due to ancillary detector limitations.
When the button is Green the GRIFFIN HPGe clovers simulated efficiency curve is included in the plot (Configuration options below). Click the button to remove HPGe and the button will turn grey to indicate this.
There are eight positions in the GRIFFIN support structure where LaBr3 fast scintillators can be installed for fast-timing measurements of gamma rays.
When the button is Orange the LaBr3 detector simulated efficiency curve is included in the plot. Click the button to remove the LaBr3 and the button will turn grey to indicate this.
Click the 'Save Plot' button and a png version of the plot on the screen will be downloaded to your computer. The default filename is 'efficiencyPlot.png' and the filename to be used appears to the right of the 'Save Plot' button. You can change this by clicking and editing it.
Changing the numbers which appear either side of the 'E' will change the x axis limits of the plot. These represent the lower and upper energy values.
Changing the numbers which appear either side of the 'effic.' will change the y axis limits of the plot. These represent the lower and upper efficiency values to be displayed.
The distance of the HPGe clover detector front face from the source location can be selected as 11cm (High-Efficiency Mode) or 14.5cm (Optimized Peak-to-Total Mode). Click on the number and a drop-down menu will appear, click on the value you want to select it.
The number of HPGe clovers included in the simulated performance.
- 8 = Just the eight HPGe clovers in the corona at theta=90 degrees are included
- 12 = The eight corona HPGe and four lampshade HPGe (theta=45 or 135) are included
- 16 = All HPGe included; eight corona, 8 lampshade
In beta-decay experiments involving large Q values, background in the HPGe detector can be observed from beta particles and their resultant bremsstrahlung radiation. Inserting a plastic (Delrin) absorber between the vacuum chamber and the HPGe will reduce the effect of this background, but also reduce the HPGe efficiency of low-energy gamma rays. Click on the word 'Delrin' and a drop-down menu will appear, click on the value you want to select it.
Using the Plot of the Data
- Move your mouse over the plot to display the efficiency at that energy for each of the detector systems which are active.
- Single click to set the energy in the 'Singles Efficiency' and 'Coincidence Efficiency' boxes below the plot.
- Drag and drop horizontally on the plot to zoom the x axis.
- Drag and drop vertically on the plot to zoom the y axis.
- Double-click on the plot to unzoom.