n-xyter for diamond detectors - gsi · nxyter chip. simulation model doesn't match exactly to...
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NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
n-XYTER for diamond detectors
Rafał LalikR.Lalik@gsi.de
UST-AGH Cracow, GSI Darmstadt
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Contents
(1) Introduction to nXYTER
(2) Overview of requirements for diamond detector
(3) Simulations
(4) Conclusions and possible future developments
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
n-XYTER: The DETNI Neutron Detector Readout ASIC
Neutron – X, Y, Time and Energy ... RFrontEnd: 128 channels Ready for different popular input signals Charge sensitive preamp and peak detector Time stamping with 1ns LSB and 2ns resolution Peak detection and analogue storage (10 bit electronic storage) Purely data driven, autonomous hit detection (self triggered) Average per channel hit rate 160 kHz with 10% dead time
(determined by pile up on slow channel)
Readout: Per channel analogue energy and digital timestamp FIFO (1ns res.) Derandomizing, specifying Token Ring readout at 32 MHz
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Input side of nXYTERWire connectionsshould be well definedbefore tests.
Photo: U. Trunk
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
n-XYTER architecture
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Analogue Signal Sequence (Test channel)
Trigger pulse
Slow channel
Fast channel
Comparator output
It really works!
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
General Purpose
nXYTER is designed to use for neutronmeasurements, but also can be used with:➔ Silicon strip detectors (STS)➔ Gas detectors (GEMTPC)➔ Other applications
Do we can use nXYTER forSingle and PolyCrystal Diamond Detectors?
Lets investigate it!
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Questions and input data
NXYTER is designed for 30 pF input (detector) capacitance. DD give us the order of 1 pF.
Questions are:
➔ signal response for so low capacitance
➔ noise
➔ Discrimination Time and TimeWalk
Tested DD has pixel configuration and 5x5 mm of total area (3 pF):
➔ 9 pixels 1.67x1.67 mm, 0.33 pF each pixel➔ 16 pixels 1.25x1.25 mm, 0.187 pF each pixel
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Simulations
Simulation model of nXYTER exist. It is very good approximation to real electrical model.
Simulations have been done by Mircea Ciobanu.
Simulations include:
➔ Simulation model of nXYTER
➔ Noise source
➔ Simulation model of detector.
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Simulation model od n-XYTER
pics and data: M. Ciobanu
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Noise parameters
0.0000000 0.0000005 0.0000010 0.0000015 0.0000020
-0.02
-0.01
0.00
0.01
0.02
0.03
Y A
xis
Titl
e
X Axis Title
noise1.dat
-0.03 -0.02 -0.01 0.00 0.01 0.02 0.03 0.04
0
500
1000
1500
2000
2500
3000
Data: Bin2_Counts1Model: GaussEquation: y=y0 + (A/(w*sqrt(PI/2)))*exp(-2*((x-xc)/w)^2)Weighting: y No weighting
Chi^2/DoF = 1110.57988R^2 = 0.9991
y0 -3.53921 ±12.47874xc -0.00071 ±0.00004w 0.01121 ±0.00011A 40.14697 ±0.45182Y
Axi
s T
itle
X Axis Title
noise1.dat
σn=5.65 mVRMS
6σn
0.00E+000 1.00E+009 2.00E+009 3.00E+009 4.00E+009 5.00E+009 6.00E+00910-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
10-10
10-9
10-8
Frequency (Hz)
Po
wer
-10000-8000-6000-4000-2000
02000
0.00E+000 1.00E+009 2.00E+009 3.00E+009 4.00E+009 5.00E+009 6.00E+009Frequency (Hz)
An
gle
(deg
)
1GHz
pics and data: M. Ciobanu
Noise model used in simulations.
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Step Pulse Response➔ 1 fC Step Pulse response
➔ CDET
= 1, 2, 4, 8, 16, 32, 64 pF
S-voltage vs. timePZ-voltage vs. timeE-voltage vs. time
pics and data: M. Ciobanu
Noise
0 10 20 30 40 50 60 700
500
1000
1500
2000
No
ise
[e]
CDET
[pF]
E PZ S
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Step Pulse Response
1 fC Step Pulse response pics and data: M. Ciobanu
E-out
PZ-out
S-outCDET=1pF CDET=30pF
Sensitiv. tPK tR Slope[mV/fC] [ns] [ns] [V/μs]
Eout 9.95 9.09 1.49 24.5 0.5 10.2 16.3 0.71PZout 9.63 6.61 1.03 11.4 0.44 6.2 17.6 0.88Sout 103.9 89.67 11.6 18.3 6.1 10 13.8 7.4
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Electrical noise
1 fC Step Pulse response pics and data: M. Ciobanu
1pF Sensitiv. Noise (500ns) Slope σT
[mV/fC] [mVRMS] [e] [V/μs] [ps]Eout 9.95 0.290 182 16.3 18PZout 9.63 0.289 188 17.6 17Sout 103.9 0.856 52 13.8 62
30pF Sensitiv. Noise (500ns) Slope σT
[mV/fC] [mVRMS] [e] [V/μs] [ps]Eout 9.09 1.472 1012 0.711 2070PZout 6.61 1.396 1320 876 1590Sout 89.7 11.49 800 7.11 1640
Adjust input serial noise as to obtain shaper equivalent outputnoise of 800 ENC corresponding to nXYTER performance.
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Electrical noise
pics and data: M. Ciobanu
CDET=1pF CDET=30pF
1 MIP = 22000 e (0.3mm Si) = ~ 3.5 fC
with noise
without noise
The response to Si equivalentcurrent generator (0.8 MIP)
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Discrimination Time
pics and data: M. Ciobanu1 MIP = 22000 e (0.3mm Si) = ~ 3.5 fC
Cdet = 1 pF Cdet = 30 pF
2 4 8 16 32 64 128 2560
1
2
3
4
5
6
7
LE
Dis
crim
inat
ion
time
[ns
]
Qinp [fC]
E PZ S
1 2 4 8 16 32 64 128 2560
5
10
15
20
25
30
LE D
iscr
imin
atio
n tim
e [n
s]Qinp [fC]
E PZ S
Discrimination time for two extreme cases: Cdet = 1 pF and 30 pF
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Time Walk
pics and data: M. Ciobanu1 MIP = 22000 e (0.3mm Si) = ~ 3.5 fC
Cdet = 1 pF Cdet = 30 pF
Time resolution for two extreme cases: Cdet = 1pF and 30pF
2 4 8 16 32 64 128 256
0.025
0.05
0.1
0.2
Tim
e r
eso
lutio
n [n
s]
Qinp [fC]
E PZ S
1 2 4 8 16 32 64 128 256
0.0625
0.125
0.25
0.5
1
2
4
8
Tim
e r
eso
lutio
n [
ns]
Qinp [fC]
E PZ S
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Future developmentIn next step we can start to do tests
with existing/being developednXYTERs boards, ie.
nXYTER GEMTPC board.
Advantages:
➔ 2 nXYTER chips on board.
➔ Very short connection (~10mm) on middle channels –low input capacitance!
➔ ADC (10 or 12bits) on board.
➔ Existing ROC – we can automate the measurements process.
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Conclusions
➔ Simulations works and gives us very interesting informations about data proceedings on the nXYTER chip. Simulation model doesn't match exactly to nXYTER electrical schematic – but is very good approximation.
➔ Simulated noise on fast shaper output is 52 EMC (for 1 MIPS input signal and 1 pF detector capacidance) – excelent S/N ratio!
➔ Signal processing is very fast – of the order of few ns.
➔ It looks like nXYTER is very good readout chip for Diamond Detectors, maybe even better than for Silicon Detectors ;)
➔ Beware! It is very important to keep total input capacitance (pixel+connection cables) lower than 1 pF – for 16 pixels detector (5x5 mm) suggested is 0.8 pF of total input capacidance.
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Contact
➔ Rafał LalikAGH-UST Cracow, Faculty of Physics and Applied Computer ScienceGSI Darmstadt - DetectorlaborR.Lalik@gsi.de
➔ Christian J. SchmidtGSI Darmstadt - DetectorlaborC.J.Schmidt@gsi.de
➔ Mircea CiobanuGSI Darmstadt - DetectorlaborM.Ciobanu@gsi.de
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
References
➔ Mircea CiobanuIs a Shaper Amplifier needed in the time branch after a CSA?
NoRHDia Workshop 2008, GSI Darmstadt, June 10th 2008
Questiontime
Thank you for your attention.
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