detection plan for stein, telescope of the space mission cinema 1 august 3td 2011-diana renaud

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Detection plan for STEIN, telescope of the space mission CINEMA

August 3td 2011-Diana Renaud

August 3td 2011-Diana Renaud 2

• STEIN has 32 detectors : neutral atoms, electrons ans ions• Energy range : 2 – 300 keV (for electrons)• FOV

• Charge particle : 40° x 70°• ENA : 20° x 80°

• Energy resolution : 1 keV• Possible to generate precise particle spectra

• Dectector : Silicon Semiconductor Dectector with thin entrance window

• Noise performance of IDeF-X : possible to exploit the extremely low capacitance of these detectors

Detection plan


Detectors


• SSD: reverse-biased silicon diode (p-n junction)• Main goal : minimize the diode reverse-leakage current (due to the

generation of carriers in the depletion region)

• Minimization of the noise• High quality float-zone refined silicon

• Interests of ultra-pure SC: large depletion layers

low defect concentrations => large lifetimes

• Gettering layer during process of fabrication• Define the size of the detector

Fabrication of the detectors

Comparison of 2 devices realized with and without the gettering layer


About the fabrication of the detectors

High purity Si (n-type)

SiO2

n+ polysilicon gettering layer (~ 1m)

p+ B - implant

High purity Si (n-type)

SiO2

n+ polysilicon (100Å – 200Å)

p+ B - implant

Al Electrode

Before removing the gettering layer Final structure of the detector

•For flashing detectors: thickness of Al layer is determined by simulation and is about 900 Å


Electrical tests

Probe card Frame to maintain detectors


• Capacitance vs bias voltage

Upcoming tests

Results of THEMIS detectors

by measuring the capacitance vs bias voltage we can obtain the voltage at which the detector is fully depleted.In the case of THEMIS detector, it fully depletes by about 28 V.


• Impurities concentration measurement• We can determine the final concentration by measuring the

capacitance and then plotting 1/C² vs bias volatage

Upcoming tests


• Current vs biased voltage

Upcoming tests

This characteristic gives the leakage current for each pixel vs bias voltage


Tests with IDeF-X : • Characterization of the front-end electronics without

detectors to determine the gain and noise vs the peaking time (performance evaluation of the circuit)• Simulation of a detector

Tests with IDeF-X and detectors : • Electrical test• Test with sources for the spectroscopy : evaluation of

the performances

Upcoming test


• Further analyze the correlation between the results obtained by spectroscopy and those obtained by measurement noise (without source).• Extract the intrinsic resolution of the detector and check

that all the noise components are clearly identified.• If measurements are perfect, spectral resolution should be a

composition of the two individual components : electronic noise and the intrinsic resolution of the detector

Suggestions for the interpretation of results

FanoFWHM EENCFWHME ²²)( (theoretical value)

detection plan for stein, telescope of the space mission cinema 1 august 3td 2011-diana renaud

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