BONNER SPHERES SPECTROMETER

Through the comparison between the counts detected by each sphere, it is possible to determine the incident neutron energies. These data must be processed by an unfolding code to calculate the neutron spectrum.

An accessory set is available upon request to extend the energy range up to 10 GeV.

The proportional counter is connected to a compact electronic module, housed in 2.5 cm diameter aluminum cylinder with a length of 7.6 cm, having the following main characteristics:

• Precision wide band charge sensitive pre-amplifier followed by an amplifier
• Twelve-turn trim pot to finely tune the amplifier sensitivity to the desired level to obtain a good high voltage plateau

• Discriminator circuit that produces, when a charged event is detected, a TTL pulse (width adjustable from 40 to 500 ns)
• Threshold control trim pot allowing to control the discriminator level
• Analog monitoring test point allowing direct monitoring of amplified charged events using an oscilloscope
• High performance high voltage generator, adjustable over a range of 0-2200 V
• Test point to measure and adjust the high voltage setting

The central acquisition box is based on 8-CH TTL hi speed DIO modules, a real-time processor and a reconfigurable field-programmable gate array. The central box is connected to a PC through an Ethernet cable, and is programmed to continuously acquire the counts coming from the detectors, also when the acquisition PC is off.

A user-friendly dedicated acquisition software is installed on the PC; it allows to start and stop the measurements, to modify the parameters and to visualize the saved data.