1. On behalf of the GEMs for CMS Collaboration
Status of no-stretch no-spacer GEM assembly. The NS2 Technique Method and experimental results
Laura Franconi
Andrey Marinov
Rui de Oliveira
On behalf of the GEMs for CMS Collaboration

2. Older techniques Thermal stretching and gluing. Honeycomb method:
The NS2 Technique

3. NS1 and NS2
NS1 is relaying on the elastic properties of the periphery frame
Readout PCB
GEMs
The screw is pushing the frame before the stretching.
Drift
Detector base
Readout PCB
The screw is pulling out the console
GEMs
Detector Base
Drift
The NS2 Technique

4. First prototype: the NS1 (10x10)cm2
Gain up to 3·104
Good uniformity across the entire surface
Good shape of the pulse height spectrum
The NS2 Technique

5. NS2 (30x30) cm2
The (10x10) cm2 NS2 GEM detector gave excellent results in terms of
Gain
Uniformity across the chamber, indicating that the stretching is uniform on the whole surface
These results encouraged us to build the (30x30) cm2 triple GEM detector
The NS2 Technique

6. 30x30cm GEM detector based on NS2 technique
A (30x30)cm2 GEM foil before stretching.
The same foil after the stretching, already inserted in the detector’s frame.
The NS2 Technique

7. NS2 (30x30) cm2 – The frame
The Read-out board with labels of the different sectors. Lengths of the different strips are indicated.
Strip Pitch = 0.8 cm (in all the surface)
Drift plane with the pins for the HV connections and a particular of the new Ceramic HV divider.
The NS2 Technique

8. NS2 (30x30) cm2 – Tests
Measurements of the (30x30) cm2 performed in all the sectors with 2 gas compositions:
Ar/CO2 (70/30)
Ar/CO2/CF4 (45/15/40)
Chamber irradiated with 8 keV X-rays gun
X-rays generator’s settings: 2mA, 20kV
Collimator diameter
2 mm for counts, pulse height spectra, gain calibration and rate capability
6 mm for gain stability
The NS2 Technique

9. Rate measurements
The NS2 Technique

10. Pulse Height Spectra
The NS2 Technique

11. Gain Calibrations
Good overlap of the curves relative to different sectors in the same gas composition
The NS2 Technique

12. Gain Stabilities
The NS2 Technique

13. Rate Capability
The NS2 Technique

14. Rate Capability in Time
The NS2 Technique

15. Future Plan Producing NS2 GE1/1 CMS baseline detector
The NS2 Technique

16. Thank you
The NS2 Technique