1. Same geometry, but different size of the rim
RUI: SAME WEIZMANN GEOMETRY
WEIZMANN
With rim
PARAMETERS:
Diameter = 0.3 mm
Pitch= 0.7 mm
Thickness = 0.4 mm
Gas: Ar/CO2 – 70/30
Without rim
RUI: WITHOUT POLISHING
RUI:CHEMICALLY POLISHED
THGEM: same geometry

2. Before and after the chemical polishing
REMARKS: different aspects of the rim after the two different treatments!
THGEM: same geometry

3. THGEM: Electro-chemical polished
PARAMETERS:
Diameter = 0.3 mm
Pitch= 0.7 mm
Thickness = 0.4 mm
Rim = 0 mm
Gas: Ar/CO2 – 70/30
GEOMETRICAL CONFIGURATION
THGEM
DRIFT
ANODE
Thickness
6.5 mm
5mm
A picture taken by the microscope: it’s to remark the rim after the electro-chemical polishing. For a best quantification of the rim it’s convenient to cut and to observe the cross-section avoiding the optics effects present in the current picture.
THGEM electro-chemical polished

4. Current measurement setup
Back view of the picoamperometer
Glass box – N2 is flushing
input
HV source
Triaxial cable
floating
REMARKS: it’s not visible, but there’s an internal connection (“meter-connection”) in the black “HV input” activated by selection on the picoamperometer before starting the measurement
Grounded to CERN ground

5. Current measurement (behaviour)
∆V= 1KV applied to the electrodes
THGEM electro-chemical polished

6. Current measurement (total data)
First 2 values ~ 2nA
During the initial 30 seconds there are some fluctuations maybe due to the stabilization of the voltage on the instrument and/or some external causes which perturbed the measurement (very sensitive to the movements around the setup)
THGEM electro-chemical polished

7. Induction scan & its energy resolution
Working conditions:
Edrift=2 KV/cm
∆V=1.475 KV
THGEM electro-chemical polished

8. Drift scan & its energy resolution
Working conditions:
Einduction=3 KV/cm
∆V=1.475 KV
THGEM electro-chemical polished

9. Strange behaviour for the energy resolution
Working conditions:
Einduction=3 KV/cm
∆V=1.475 KV
THGEM electro-chemical polished

10. Scan voltage and rate capability
Einduction=3.5 KV/cm;
Edrift=1.5 KV/cm
∆V=1.475 KV
Source collimated
1.Voltage Scan
2.Rate capability
THGEM electro-chemical polished

11. THGEM electro-chemical polished
Gain estimation
∆V=1.475 KV, G~1550
∆V=1.45 KV, G~950
∆V=1.425 KV, G~590
∆V=1.4 KV, G~360
∆V=1.375 KV, G~220
Einduction=3.5 KV/cm;
Edrift=1.5 KV/cm
Source collimated
THGEM electro-chemical polished

12. THGEM electro-chemical polished
Time measurement
An example of the spectrum acquired
pedestal
Pulse test
Some problems with the fit (black spikes)
Possible explanation: variation of the temperature
THGEM electro-chemical polished

13. THGEM: kapton multilayers & chromium (103Å thick)
NO ELECRICAL CONNECTION  NO CHARACTERIZATION
PARAMETERS:
Diameter = 0.5 mm
Pitch= 0.8 mm
Thickness = 0.6 mm
Rim = 0 mm
Gas: Ar/CO2 – 70/30
Zoom
THGEM: kapton substrate chromium layer

14. THGEM: kapton multilayers & copper (5 μm thick)
PARAMETERS:
Diameter = 0.5 mm
Pitch= 0.8 mm
Thickness = 0.6 mm
Rim = 0 mm
Gas: Ar/CO2 – 70/30
GEOMETRICAL CONFIGURATION
THGEM
DRIFT
ANODE
Thickness
6.5 mm
5mm
THGEM: kapton substrate 5μm Cu

15. THGEM: kapton substrate 5μm Cu
Current measurement
Jumps due to the changing of the range
∆V= 1KV applied to the electrodes
THGEM: kapton substrate 5μm Cu

16. Comparison of 2 spectrum with different source collimation
Einduction=3.5 KV/cm;
Edrift~1.5 KV/cm
∆V=1.71 KV
THGEM: kapton substrate 5μm Cu

17. THGEM: fibre glass with asymmetric rims
side A
side B
PARAMETERS:
Diameter = 0.3 mm
Pitch= 0.7 mm
Thickness = 0.4 mm
RimsideA = 0.1 mm
RimsideB = 0.03 mm
Gas: Ar/CO2 – 70/30
GEOMETRICAL CONFIGURATION
Some garbage
THGEM
DRIFT
ANODE
Thickness
6.5 mm
5mm
THGEM asymmetric rims

18. Current measured Voltage on
Voltage off and cables disconnected from the instrument
Voltage off
Voltage off
THGEM asymmetric rims

19. The charging-up movie: reading from the bottom electrode
Einduction=4 KV/cm;
Edrift~1 KV/cm;
∆V=1.18 KV;
Collimated X-Ray source (~ 1 mm of diameter);
The smallest rim (30μm) is on the top of the THGEM
Local effect next step THGEM submitted to the cleaning procedure done by Rui
THGEM asymmetric rims

20. THGEM: fibre glass without rim
PARAMETERS:
Diameter = 0.3 mm
Pitch= 0.7 mm
Thickness = 0.4 mm
Rim = 0 mm
Gas: Ar/CO2 – 70/30
GEOMETRICAL CONFIGURATION
THGEM
DRIFT
ANODE
Thickness
6.5 mm
5mm
THGEM without rim

21. Gain estimation of this THGEM for ∆V=1.35KV is ~300
Rate capability
Averaging the current plateau and plotting vs the X-Ray current
Gain estimation of this THGEM for ∆V=1.35KV is ~300
THGEM without rim

22. Induction scan, its energy resolution & comparison with the behaviour of THGEM electro-chem. pol.
Edrift~1.5 KV/cm
∆V=1.35 KV
Rate= 1.6 KHz
Collimated source
Gas flux: 5l/h
Working conditions
Same working conditions except for the gas flow into the chamber of the THGEM electro-chem. polished was higher (8l/h) and the drift field value
THGEM without rim

23. Drift scan, its energy resolution & comparison with the behaviour of THGEM electro-chem. pol.
Einduction~3 KV/cm
∆V=1.35 KV
Rate= 1.7 KHz
Collimated source
Gas flux: 5l/h
Working conditions
Same working conditions except for the gas flow into the chamber of the THGEM electro-chem. polished was higher (8l/h)
THGEM without rim

24. Consistence between pulse height spectra and current measurement always from the anode
THGEM without rim

25. Position scan before and after time stability measurement
An example of the spectrum
Collimated source 0.2 KHz
Same working conditions:
Einduction~3.5 KV/cm
Edrift~1.5 KV/cm
∆VSTD=1.35 KV
∆VELECTRO=1.45 KV
Rate= 0.84 KHz
Collimated source
THGEM without rim