Download ASIC Development

Low Noise Charge Sensitive
Preamplifier Development
for the PANDA Calorimeter
Design and Measurements of the
APFEL - Chip
Peter, Wieczorek - EE
Outline
1.
2.
3.
PANDA – Experiment Overview
Design of the APFEL – Chip
Measurements of the ASIC – Performance
19.05.2008
Peter, Wieczorek - EE
1. The PANDA-Experiment
19.05.2008
Peter, Wieczorek - EE
PANDA - Experiment
PANDA
19.05.2008
Peter, Wieczorek - EE
Physical Goals
The aim of the PANDA – experiment is the better understanding of the
strong interaction as well as the structure and dynamics of hadrons
Studies of bound quarks using
p Momentum [GeV/c]
meson spectroscopie
 Bound qq – states
 Theoretical description
by QCD
Looking for exotic states
Hybrids (qqg)
Molecules
Gluons
Mesons
Glueballs (ggg)
Molecule
Mass [GeV/c2]
19.05.2008
Peter, Wieczorek - EE
Charmonium Spectra
Mass
[GeV/c2]
p Momentum
[GeV/c]
Charmonium: cc – quarks
Spectra of exicited states
Activation of all states by pp –
interaction
Search of the theoretical
predicted mesons
Detection of charged and neutral particals over the whole solid angle
19.05.2008
Peter, Wieczorek - EE
PANDA - Detector
Solenoid
Target
Myondetector
Dipol
RICH
p
STT
DIRC
EMC
19.05.2008
MVD
STT
Peter, Wieczorek - EE
EMC
HC
Electromagnetic Calorimeter
Photon detection by the
electromagnetic calorimeter
11000 crystals (Barrel)
Used scintillator material:
PbWO4
To increase the crystal light
yield the calorimeter will
operate at a temperature of
T = - 20°C
19.05.2008
Peter, Wieczorek - EE
Scintillator Material
Output Voltage
Photon

e
-

e
+
λmax = 430 nm
…..
Scintillator Crystal
Avalanche Photodiode
Readout Electronics
?
19.05.2008
Peter, Wieczorek - EE
Requirements
Noise:
ENC = 4500 e- ( ≈ 0,7 fC)
Max. input charge:
Qmax = 7 pC
Dyn. range:
10000
Event rate:
≈ 350 kHz
Avalanche photodiode:
Detector capacitance:
Cdet = 300 pF
Dark current:
Id = 50 nA at M = 50
Operation Temperature:
T = -20°C
Power dissipation:
P < 60 mW/Channel
Very compact calorimeter design
 High integration level of the readout electronics
Development of an application specific integrated circuit
19.05.2008
Peter, Wieczorek - EE
2. APFEL - Chip Design
(Asic for Panda Frontend ELectronics)
19.05.2008
Peter, Wieczorek - EE
Noise Calculations
W
Feasibility study for integrated
calorimeter readout electronics
Area ~
The dominant noise source is the
input transistor
Signal
Noise
Transistor noise is a function of
Transistorwidth W
Current Ids
Ids
Integration time 
Preselection of the free parameters:
W = 12000 µm, Ids = 2 mA and  = 250 ns
19.05.2008
Peter, Wieczorek - EE

Readout Concept
Readout is realized in three stages
First readout stage is a low noise Charge Sensitive Amplifier (CSA) based
on a folded cascode circuit
Second stage consists of a differentiator and three first order integrators
Semi gaussian pulse form
Improvement of the Signal-to-Noise-Ratio (SNR)
The last stage is an output/line driver, which can cope with a load of 10
pF || 50 kΩ
19.05.2008
Peter, Wieczorek - EE
Concept of the Readout Electronic
Charge Sensitive
Amplifier
Shaper Stage
Output Stage
-
Preamp
First Shaper
Second Shaper
Third Shaper
19.05.2008
Peter, Wieczorek - EE
Chip Overview
Used prozess:
350 nm - CMOS
Channel 1
Output Stage
Charge Sensitive Preamplifier
Shaper Stage
Channel 2
Dimensions:
3,3 mm x 3,3 mm
Pins: 64
Components:
Transistors: 4841
Capacitors: 1729
Resistors: 386
Voltage References
19.05.2008
Peter, Wieczorek - EE
3. Chip Characterisation
19.05.2008
Peter, Wieczorek - EE
PCB for the ASIC Characterisation
For the characterisation of the
ASIC a PCB was designed
Power supply (Vddc,Vddt): 3.3 V
For measurements a voltage step
ΔV injected to a coupling
capacitance
With the voltage step ΔV and the
capacitance Cin the injected input
charge can be calculated to
Qin = Cin ΔV
19.05.2008
Peter, Wieczorek - EE
Cooling
Input
Output
PT100
Cooper
Peltier Element
19.05.2008
Peter, Wieczorek - EE
For cooling an external
controlled Peltier-Element is
used
Measurements in the range of
T=-20°C up to T=+20°C could
be realized
The current ASIC temperature
is measured by a PT100
Measurement Setup (1)
Measurements are performed in
an evacuated environment
Water cooling for heat sinking
Electrical connections are done
via BNC - connectors
19.05.2008
Peter, Wieczorek - EE
Measurement Setup (2)
Defined input step ΔV by
an AWG
Power Supply
Signal Generator
AWG
Measuring the output
pulse characteristics at
Different temperatures
Different detector
capacitances
Oscilloscope
Programming
19.05.2008
PCB
Peter, Wieczorek - EE
Temperature
Controller
Output Pulse
Amplitude & Rise time
19.05.2008
Noise
Peter, Wieczorek - EE
Measured Results
Requirements:
Results at
T = - 20° C
Unit:
Noise:
4500
4456 ± 35
e-
Max. input charge:
7
7,84
pC
Dyn. range:
10000
10889
1
Integration time:
250
248 ± 3
ns
Max. event rate:
350
500
kHz
Power:
< 60
52 ± 1
mW
19.05.2008
Peter, Wieczorek - EE
Status
The developed APFEL- chip fulfills all requirements
First preliminary radiation tests have been done
Next steps
More detailed radiation tests are necessary
Readout of an array of crystals
19.05.2008
Peter, Wieczorek - EE
Thank you for your attention
19.05.2008
Peter, Wieczorek - EE