DIPIX pixel detector designed in SOI technology

Measurements of DIPIX2 SensorsCZ-n, FZ-n and FZ-p

Mohammed Imran Ahmed

Supervisor:

Prof. Marek Idzik (AGH)Dr. Piotr Kapusta (IFJ)Prof. Michal Turala (IFJ)

March 16, 2012

Imran (AGH and IFJ, Krakow Poland) Measurements of DIPIX2 Sensors March 16, 2012 1 / 29

Outline

1 IntroductionCZ-n, FZ-n and FZ-p

2 Study of Pixel BehaviourSaturation Test

3 Laser MeasurementsHalo IssueOptimization of Back Voltage and Integration time

4 Measurements with Americium sourceData CleaningSignal Clusters and Energy plotsComparison of ENC and SNR for CZ-n and FZ-n

5 Conclusion

Outline

5 Conclusion

CZ-n, FZ-n and FZ-p

DIPIX is a Dual mode Integration type PIXel with reduced pixel sizeof 14 µm.Each pixel is also provided with and without CDS (Correlated DoubleSampling).Three detectors are designed in this Family of DIPIX2 (CZ-n, FZ-nand FZ-p).FZ-p sensor : Miss-handling of wafer (p-substrate is changed to ’n’instead of ’p’) result wrong implantation.Total number of pixels 256x256 divided into two regions, each with asize of 128x256 pixels.

CZ-n, FZ-n and FZ-p

DIPIX is a Dual mode Integration type PIXel with reduced pixel sizeof 14 µm.Each pixel is also provided with and without CDS (Correlated DoubleSampling).Three detectors are designed in this Family of DIPIX2 (CZ-n, FZ-nand FZ-p).FZ-p sensor : Miss-handling of wafer (p-substrate is changed to ’n’instead of ’p’) result wrong implantation.Total number of pixels 256x256 divided into two regions, each with asize of 128x256 pixels.

Outline

5 Conclusion

Saturation Test

Saturation test is to check whether the detector is capable of operating inlong run measurements (INTPIX3 was saturating).

Test Setup :

Parameters DIPIX2Environment DarkSignal NoNo. of Frames 60000Integration Time 500µsScan Time (pixel readout time) 640 ns/pixelRST time without cds and with cds 2040 ns and 2160 nsRSTV for N and P (wafer) 750mV and 1300mV

The back voltage for CZ-n = 100 V, FZ-n= 70 V.

Saturation Test

Test Setup :

Saturation Test

Test Setup :

Saturation Test of CZ-n

Figure: Saturation test of CZ-n with CDS. (3 graphs each with 20000 framesmeasured subsequently.)

Figure: Saturation test of CZ-n without CDS.

Saturation Test CZ-N Zoom

Figure: Left fig: with CDS, Right fig: without CDS

Saturation Test of FZ-n

Figure: Saturation test of FZ-n with CDS. (3 graphs each with 20000 framesmeasured subsequently.)

Figure: Saturation test of FZ-n without CDS.

Saturation Test FZ-n Zoom

Figure: Left fig: with CDS, Right fig: without CDS

Saturation Test

Summary

DIPIX is not saturating (contrary to INTPIX3) and so it may work forlong time run.

Small initial changes in number of counts may probably be reduced bymaintaining a constant temperature.

Strange oscillations using CDS. More study of CDS readout is needed.

Saturation Test

Summary

DIPIX is not saturating (contrary to INTPIX3) and so it may work forlong time run.

Small initial changes in number of counts may probably be reduced bymaintaining a constant temperature.

Strange oscillations using CDS. More study of CDS readout is needed.

Outline

5 Conclusion

Laser Setup

Laser Details

Laser Driver PDL 800-DFrequency 80 MHzModes of operation PulseLaser Head wavelength 1060 nm3D setup X,Y and Z

Laser Setup

Laser Details

Laser Driver PDL 800-DFrequency 80 MHzModes of operation PulseLaser Head wavelength 1060 nm3D setup X,Y and Z

Halo in FZ-n

Figure: Back voltage was set to a) Left fig. 10V, b) Right fig. 70V

Halo Issue

A bunch of pixels around the hit pixel(halo) having 12 to 15 % of hitpixel count is seen.

This problem is seen in all sensors. The worse is FZ-n.

Halo depends mostly on Laser Intensity (increase with intensity).

Halo in FZ-n

Figure: Back voltage was set to a) Left fig. 10V, b) Right fig. 70V

Halo Issue

A bunch of pixels around the hit pixel(halo) having 12 to 15 % of hitpixel count is seen.

This problem is seen in all sensors. The worse is FZ-n.

Halo depends mostly on Laser Intensity (increase with intensity).

Optimization of Back Voltage and Integration time

Parameters CZ-n Type FZ-n Type

Back Voltage 80V 70VIntegration Time 100µs 100µs

Table: Optimized Back Voltage and Integration Time

Optimization

The presence of halo, force us to do the scan of back voltage andIntegration time to optimize them in order to reduce halo.

Optimization is used to reduce the halo and spot size.

Optimization of Back Voltage and Integration time

Parameters CZ-n Type FZ-n Type

Back Voltage 80V 70VIntegration Time 100µs 100µs

Table: Optimized Back Voltage and Integration Time

Optimization

The presence of halo, force us to do the scan of back voltage andIntegration time to optimize them in order to reduce halo.

Optimization is used to reduce the halo and spot size.

CZ-n before and after optimization

Figure: a) Left fig. Before optimization , b)Right fig. After optimization

FZ-n before and after optimization

Figure: a) Left fig. Before optimization , b)Right fig. After optimization

Laser Measurements

Summary

Halo is seen in all sensors and depends mostly on Intensity. Is itpossible that halo is caused by large charge generation disturbing theelectric field?

Optimized Back voltage and Integration time result in smaller spotsize.

Outline

5 Conclusion

Americium Radiation Data and Setup

Am-241 source is used with the activity of 10mCi(=370MBq).

The rate of incident photon is low.

Setup is placed in black box.

Radiation Data

Type Energy

Gamma 59.5KeVGamma 26.3KeVGamma 13.9KeV

Cu L x-ray 8.01KeVNp L-x-ray 17.7KeVNp L-x-ray 20.7KeV

Radiation Data

Type Energy

Radiation Data

Type Energy

Data Cleaning using CZ-n

Integration Time and Scan Time 100 µs, 640 ns/pixelBack Voltage 80 VRSTV and RST time 750 mV, 2040 nsRun Mode calib data and signal dataCalib run (dark, no source) 500 eventsAm-241 run (dark) 20000 events

Table: Parameter setting of sensor CZ-n Type

Noise cleaning

Calib data is used to remove bad pixels.

Bad frames and common mode noise are removed from both caliband Am-241 run.

Data Cleaning using CZ-n

Integration Time and Scan Time 100 µs, 640 ns/pixelBack Voltage 80 VRSTV and RST time 750 mV, 2040 nsRun Mode calib data and signal dataCalib run (dark, no source) 500 eventsAm-241 run (dark) 20000 events

Table: Parameter setting of sensor CZ-n Type

Noise cleaning

Calib data is used to remove bad pixels.

Bad frames and common mode noise are removed from both caliband Am-241 run.

Data Cleaning

Sensor = CZ-n, CDS = no, No. of frames = 20000 Am-241 and 500calib runs.

Back voltage = 80 V, IT = 100 µs, Pixel scan time = 640 ns.

Clustering

Number of pixels in a cluster depends on deposited energy.Total 4σ threshold is use to get hit pixels and these pixels are used tofind the cluster.

Clustering

Number of pixels in a cluster depends on deposited energy.Total 4σ threshold is use to get hit pixels and these pixels are used tofind the cluster.

CZ-n signal Clusters and Energy plots

ENC and SNR Results

CZ N-Type Without CDS

Region IT(µs) Noise (ADC) Signal Noise(ADC) ENC(e−) SNR 59.5KeV (ADC)

1100 4.32 4.38 86 189 815500 - - '107 '153 812

CZ N-Type With CDS

Region IT Noise Signal Noise(ADC) ENC(e−) SNR 59.5KeV (ADC)

1100 4.53 4.59 90 180 817500 - - '117 '139 810

FZ N-Type Without CDS

1100 - - '99 '164 657500 - - '109 '150 645

2100 - - '129 '126 543500 - - '144 '113 535

ENC and SNR Results

CZ N-Type Without CDS

1100 4.32 4.38 86 189 815500 - - '107 '153 812

CZ N-Type With CDS

Region IT Noise Signal Noise(ADC) ENC(e−) SNR 59.5KeV (ADC)

1100 4.53 4.59 90 180 817500 - - '117 '139 810

FZ N-Type Without CDS

1100 - - '99 '164 657500 - - '109 '150 645

2100 - - '129 '126 543500 - - '144 '113 535

Am-241 Measurements summary

1st region is the best of all sensor (ENC=86e− and SNR=189 usingAm-241 source 59.6keV), 2nd region is having lot of bad and hotpixels.

Readout with CDS give similar results.

CDS is not working for this sensor.

SNR is worse than CZ-n, may be due to halo.

Am-241 Measurements summary

1st region is the best of all sensor (ENC=86e− and SNR=189 usingAm-241 source 59.6keV), 2nd region is having lot of bad and hotpixels.

Readout with CDS give similar results.

CDS is not working for this sensor.

SNR is worse than CZ-n, may be due to halo.

Outline

5 Conclusion

Conclusion

No saturation is found in dipix2 sensors and may work for long timerun.

With laser Halo problem can be reduced using small intensity andoptimized back voltage. Halo is not seen with americium.

CZ-n is having good SNR and ENC (86e-), whereas FZ-n is worse.

Various readout issues need to be studied (e.g. CDS and pixel scantime).

Conclusion

No saturation is found in dipix2 sensors and may work for long timerun.

With laser Halo problem can be reduced using small intensity andoptimized back voltage. Halo is not seen with americium.

CZ-n is having good SNR and ENC (86e-), whereas FZ-n is worse.

Various readout issues need to be studied (e.g. CDS and pixel scantime).

Thanks

Thank you for your attention!

DIPIX pixel detector designed in SOI technology

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