E. Baracchini - CYGNUS Gas Meeting 13th February 2020

Z scan with Fe55 on LEMON

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20 cm drift

20 x 24 cm2 readout area with 1 CMOS + 1 PMT

example of Fe55 spectrum

E. Baracchini - CYGNUS Gas Meeting 13th February 2020 �2

Z scan with Fe55 on LEMONIntegral of # of photons

from CMOS imageIntegral of PMT

signalCurrent on the

last GEM

All increasing when the source is further away from GEMs

E. Baracchini - CYGNUS Gas Meeting 13th February 2020 �3�3�3�3

from studies at CERN

E. Baracchini - CYGNUS Gas Meeting 13th February 2020

Plans & ideas

• Evaluate effect (i.e. how far from linearity?) with X-ray tube

• Evaluate the possibility of compensating by looking at the GEM2/GEM3 electric signal ratio

• Test alternative GEMs structures/stacking options (50 um,125 um, 400 um, COBRA_125)

• Try to improve light output through gas purification (we see some evidences in our data)

• ….

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E. Baracchini - CYGNUS Gas Meeting 13th February 2020

LIME prototype

PMMA vessel

PMMA frames for GEMS

2 field cage options: copper rings (see next slides) or

resistive foil (under development)

2 field cathode options:copper plate (see next slides) or mylar

foil a’ la DRIFT (under development)

E. Baracchini - CYGNUS Gas Meeting 13th February 2020

LIME status

Next steps: mount GEMs & turn it on

with cosmics

Cathode & field cage tested up to

50kV and expected currents verified

(14 uA)

E. Baracchini - CYGNUS Gas Meeting 13th February 2020

LIME next: faraday cage

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