Cologne CATHEDRAL spectrometer
CATHEDRAL is IKP's new γ-spectrometer for lifetime measurements of excited nuclear states.
Cologne CATHEDRAL spectrometer
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Optimized for Doppler shift measurements
Measurement of Doppler-shifted γ-energies by positioning the 24 detectors in rings (blue & white). The 90° ring (red) can additionally be equipped with eight LaBr detectors for Fast-Timing.
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Optimized target-detector distance
View on the upstream hemisphere with the plunger target chamber in the center. The detectors closest to the beam direction have hexagonally shaped end caps in order to position them as close as possible to the chamber at an identical distance.
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Simultaneous RDDS and Fast-Timing measurements
View on the downstream hemisphere with the eight LaBr detectors in the 90° ring.
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High efficiency for high-precision lifetime experiments
In combination with detectors for charged particles, the high γ-efficiency allows the measurement data to be sorted into particle-γ-γ coincidences and thus high-precision spectroscopy and lifetime measurements. The picture shows an array of solar cells. This is mounted at a backward angle in the plunger target chamber.
Cologne CATHEDRAL(Coincidence Arrayat the Tandemaccelerator for High-Efficiency Doppler Recoil And LaBrfast-timing measurements) is the IKP's γ-spectrometer for lifetime measurements of excited nuclear states.
Its geometry is optimized for Doppler shift measurements, RDDS (Recoil Distance Doppler Shift) and DSAM (Doppler Shift Attentuation Method). To measure the Doppler-shifted γ-energies, six HPGe (High Purity Germanium) detectors can be placed in each of a total of six "rings". These rings are located at angles of 30°, 55°, 125° and 150° in relation to the beam direction. In addition to these 24 detectors, it is possible to mount another one at 0°. There are also a total of eight positions at 90°. These can also be equipped either with HPGe, e.g. for angular correlation measurements, or with LaBr3(Ce) detectors for Fast-Timing.
CATHEDRAL offers the possibility to perform RDDS and fast timing measurements simultaneously. The absolute γ-efficiency of the 24 "ring" detectors of 5% (at 609 keV) allows both the evaluation of γ-γ-γ coincidences and, in combination with particle detectors (e.g. solar cells), of particle-γ-γ-γ coincidences.