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MUST2
SAMURAI_2018
S3-LEB-LPC
SUPERNEMO
MUGAST
EXPAND
SCALP
GALATRON
HiCARI
VELO
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Message ID: 137
Entry time: Mon Jul 3 17:28:05 2017
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| Author: |
e748 -Thomas R, Georges V, Sébastien H |
| ExpNbr: |
e748 |
| Type: |
CHIO |
| Category: |
General |
| Status: |
Fixed |
| Target-Source: |
N/A |
| Subject: |
(Tentative) Solution to recover the CHIO: it works! |
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An interview of Th, Seb and Georges by Valérie on July 3rd.
Please indicate complements or corrections on this summary of the ionization chamber situation.
We list here the problems during the last days and the solution adopted to recover it...
The ionization chamber was not running. now it works with a modification of the capacitor connexion (see scheme +oscilloscope vizualization)
Two registered problems (for the moment, Ndlr Vlx):
I. The cables for the ChIo voltages were inverted.
First time inside the Chamber. On Thursday evening, signals with the Alpha source were correct but it appeared that
the output voltages were not correctly set.
This was solved on Friday 30th June opening the chamber and connecting again correctly INSIDE the chamber.
Secondly: it was seen today 3rd that the cables are not properly connected OUTSIDE the chamber,
they were inverted again between Anode and grid. Preamplis were burnt out.
On 4 available Preamplis (2 of 700 mV/MeV; 2 of 1 V/MeV) none remains.
We are running with one of 300 mv/MeV.
II. problem of the decoupling capacitance - off on the anode.
Possible solution could be to put the capacitance on the acceleration grid.
Same voltages will be applied, as before.
Proposed scheme (see photograph below, of the drawing made by Thomas):
________________________________ Cathode -3kV
-------------------------------- Frisch 0V
_______________________________ acceleration grid 960V <-----put capa HERE
________________________________Anode +2600 V <----capa (down! burnt out) was HERE
The electrons will be collected on the grid (if everything works well..)
See the oscilloscope view (Mtime 4µs):
- ch1 (1V) (yellow) analogic signal ChIo sent to ADC
- ch2 (50mV)(blue) PAC ChIo
- ch3 (1V) (pink) signal output of the discri
- ch4 (1V) (green) trigger LISE |
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