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M. Staib , M. Abercrombie, B. Benson, K. Gnanvo, M. Hohlmann Department of Physics and Space Sciences Florida Institute of Technology
M. Staib, M. Abercrombie, B. Benson, K. Gnanvo, M. Hohlmann
Department of Physics and Space SciencesFlorida Institute of Technology
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Presentation Outline
• GEM detector design for ft3 MT station
• GEM stretching and framing by IR thermal method
• Gain uniformity measurements of detectors fabricated using this new method
• Future work regarding implementation of these detectors into our ft3 muon tomography station
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Gas Electron Multiplier (GEM) Detector
V
μ-
e-
GEM foil under electron microscope (F. Sauli)
~400 V
30 cm x 30 cm triple-GEM detectors for muon tomography based on design used for the COMPASS experiment at CERN and are
operated in Ar/CO2 70:30 mixture
X-Y Cartesian readout strips 1568 strips per detector
400 μm pitch
Triple-GEM Detector for MT station
COMPASS Design
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Assembled GEM Detector
Drift Cathode
GEM foil
FR4 Spacer Frame
X-Y Readout
Nucl. Inst. and Meth. A 490 (2002) 177–203
Traditional GEM Foil Stretching
Mechanical (INFN) Thermal (CERN/FIT)
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
• GEM foils lack mechanical rigidity and must be stretched and framed before being assembled into a detector.
• Traditional methods of tensioning the foils are expensive to implement.
• Stretching must take place under clean room conditions.
Framed GEM Foil
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Low-Cost GEM Stretching Using IR Heating
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Low-Cost GEM Stretching Using IR Heating
Two 30 cm x 30 cm detectors were assembled at FIT using GEM foils tensioned by IR heating
Framed GEM Foil
30 x 30 cm2 Active Area
HV Divider Board
128
Strip
Rea
dout
Con
nect
ors
Gas In
Gas Out
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
CMS Upgrade Using GEM Detectors
Framed GEM Foil
Gas In
Potential muon upgrade at CMS using GEMs for triggering & tracking
~1 m
(A. Sharma, S. Colafranceschi)
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Scaled-up IR Array for Large Area GEM
We have scaled up our design in order to stretch foils as large as 1 m x 0.5 m
Wedge shaped drift foil for proposed CMS endcap upgrade using GEMs in the high-η region
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Temperature profile of Plexiglas stretching frame
Scaled-up IR Array for Large Area GEM
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Gain Uniformity Measurement
The gain uniformity was measured using spectra obtained from a Cd-109 gamma source.
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Why use 109Cd for Uniformity Measurements?
Copper K-line Emission
55Fe Spectrum (16 Hours) 109Cd Spectrum (1 Hour)
5.9 keV
2.9 keV
• Only about 5% of the x-rays produced by 55Fe pass through the honeycomb cover into the drift region where they can be detected.
• 55Fe measurement is very slow, impractical for a large study.
• We can observe copper K-line fluorescence from within the detector using a 109Cd source.
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Gain Uniformity Measurement
Top Strip Uniformity GEM Detector 9
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Gain Uniformity Measurement
Bottom Strip Uniformity GEM 9
No-peak Measurement
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Gain Uniformity Measurement
GEM 10 Uniformity
Top Strip Uniformity Bottom Strip Uniformity
Some problems in one corner visible on both readout axes
Outline
GEM Design
GEM Stretching
IR GEM Stretching
Characterization
Future Work
Future Work
• The GEMs assembled at Florida Tech are currently en route to CERN for use in our ft3 muon tomography station.
• We are implementing full readout of all 10 detectors (~16k channels!) and will continue characterization using complete readout electronics.
• We are working with the CMS collaboration to scale up our IR stretching method for a proposed upgrade to the muon system using large area GEM detectors.
