Project number: P04/02
Final scientific report
Final scientific report
Project Title: FADC400
LNGS Access period: February 2002 – October 2003
Group Leader: H. De Kerret: College de France Paris (F)
Researchers: H. De Kerret, M. Obolenski, A. De Bellefont, D. Kryn, J. Lamblin, G. Mention: College de France, Paris (F)
Delivered access (filled by TARI administration): 260 man-days
Final scientific report (filled by group leader):
The counting Test facility is a large volume of liquid scintillator, viewed at distance by about 100 photomultipliers. The liquid used is pseudocumene. The shape of the registered pulses in such a liquid gives informations on the nature of the inoizing particule: this effect is called Pulse Shape Discrimination (PSD). An heavier particle creates a longer pulse in the medium, due to the saturation of ionization. The use of this discrimination in very big detectors is complicated, due to all the possible instrumental effect: reflections, diffusion, etc.. which can create delayed light, and spoil the discrimination. This project wants to use new tools such as the flash adc to improve the PSD and study its link to all instrumental effects..
The 4 boards installed at the CTF took data during one year without any technical problems.
The measured quantities: charge, time,etc.. were found to be in good agreement with the classical electronics (commercial ADC and TDC).
The datas taken during this period allowed a very deep understanding of the detector. Some instrumental problems in the classical electronics have been found, which were not visible without such a tool. The way the shape of pulse depends upon the interaction point was also investigated, and is still under analysis at the College de France laboratory. This opens the path to creating new analysis tool, to fully take in account such effects.
The flash adc has also the advantage to allow continuous measurement (there is no internal dead time). This allowed precise measurements of very short radioactivities (till a few nanoseconds). An example is the measurement of bismuth 212 - po 212 - pb208 (300 nanoseconds), which was much more precise with the flash adc than with classical electronics.
Unfortunately, the use of liquid scintillator was stopped during one year at the laboratory. This delayed the measurements at the LLBF (they are just beginning) and at the Borexino detector (they are intended in about one year). This last measurement will be specially important, because it will be an actual encounter with all the problems linked to the huge size of the detector, and of the light path towards pmts.
Publications (quote also planned or in preparation) (filled by group leader):
The 400 Mhz Flash ADC (in preparation)
The Borexino electronics (in preparation)
LNGS Access period: February 2002 – October 2003
Group Leader: H. De Kerret: College de France Paris (F)
Researchers: H. De Kerret, M. Obolenski, A. De Bellefont, D. Kryn, J. Lamblin, G. Mention: College de France, Paris (F)
Delivered access (filled by TARI administration): 260 man-days
Final scientific report (filled by group leader):
The counting Test facility is a large volume of liquid scintillator, viewed at distance by about 100 photomultipliers. The liquid used is pseudocumene. The shape of the registered pulses in such a liquid gives informations on the nature of the inoizing particule: this effect is called Pulse Shape Discrimination (PSD). An heavier particle creates a longer pulse in the medium, due to the saturation of ionization. The use of this discrimination in very big detectors is complicated, due to all the possible instrumental effect: reflections, diffusion, etc.. which can create delayed light, and spoil the discrimination. This project wants to use new tools such as the flash adc to improve the PSD and study its link to all instrumental effects..
The 4 boards installed at the CTF took data during one year without any technical problems.
The measured quantities: charge, time,etc.. were found to be in good agreement with the classical electronics (commercial ADC and TDC).
The datas taken during this period allowed a very deep understanding of the detector. Some instrumental problems in the classical electronics have been found, which were not visible without such a tool. The way the shape of pulse depends upon the interaction point was also investigated, and is still under analysis at the College de France laboratory. This opens the path to creating new analysis tool, to fully take in account such effects.
The flash adc has also the advantage to allow continuous measurement (there is no internal dead time). This allowed precise measurements of very short radioactivities (till a few nanoseconds). An example is the measurement of bismuth 212 - po 212 - pb208 (300 nanoseconds), which was much more precise with the flash adc than with classical electronics.
Unfortunately, the use of liquid scintillator was stopped during one year at the laboratory. This delayed the measurements at the LLBF (they are just beginning) and at the Borexino detector (they are intended in about one year). This last measurement will be specially important, because it will be an actual encounter with all the problems linked to the huge size of the detector, and of the light path towards pmts.
Publications (quote also planned or in preparation) (filled by group leader):
The 400 Mhz Flash ADC (in preparation)
The Borexino electronics (in preparation)