electronics part of ahcal calibration system
DESCRIPTION
Electronics part of AHCAL calibration system. ECFA meeting at Warszawa. Proposal for calibration system. Fast LED driver is needed for fast photodetectors… A tunable calibration light in the range 0 to 100MIP - PowerPoint PPT PresentationTRANSCRIPT
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 1
Electronics part of AHCAL calibration system
ECFA meeting at Warszawa
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 2
Proposal for calibration system
• Fast LED driver is needed for fast photodetectors…
• A tunable calibration light in the range 0 to 100MIP
• Simplification of the optical system: one LED -> one side emitting fibre, one row of scintillator tiles
• See Jara’s talk Optical part of AHCAL calibrator
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 3
Two scenarios of calibration system for EUDET AHCAL
1. Side emitting fiber for one raw, QRLed driver sitting on the side of module (endcap)
2. QRLed driver is sitting at HBU above the scintillator
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 4
Side emitting fiber version
QR driver + LED
24*3cm² area needed at the main PCB
24 fibers
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 5
Scenario with QRLed driver by scintillator
• One LED, one QRLed driver at HBU
Signals needed:
T-calib
V-calib (single ended)
power +12V
This figure is been used by Riccardo Fabbri’s talk
QRLed driver will be placed here around
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 6
Electrical block diagram of the Calibrator
QRLED 1
T-calib
V-calib
Power regulator
QRLED 24
LED1
LED24
+12V
Optical taps
- notches
- drops
# of elements compensate exp attenuation
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 7
QR LED driver, basic parameters
• Fixed pulse width 2 ÷ 10 ns
• LED is an integral part of QR driver
• Cosine waveform reduces elmag. x-talk
• PCB footprint 2 ÷ 3 cm²
• Easy power-pulsing
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 8
PIN PD response to UVLED
LED current 1V => 1A
PIN
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 9
Principal schema of QRLed driver
AA
LED
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 10
Toroidal inductors, ~ 30nH
All inductors has
Non-magnetic core
No sensitivity to external mag. field
L1L2 L3
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 11
Toroidal inductors - parameters
Inductors toroidals non magnetic core
turns L [nH] @100kHz Q @100kHz L [nH] @50MHz Q @50MHz core
L1 6 32 1.6 PE
L2 5 20 1.7 *53nH* 95 PX
L3 7 25 1.8 *56nH* 73 PX
non mag core Polyethylen PE OD = 7mm, ID = 4mm, h = 1.6mm
non mag core Pertinax PX OD = 7mm, ID = 4mm, h = 1mm
stars ** means inductors used 2.5cm terminals to measure Q @ 50MHz
it adds about 20nH to total inductance
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 12
Toroidal inductor soldered
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 13
Toroidal inductor soldered
See thickness of PCB and inductor
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 14
LED current
• Max amplitude 1A
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 15
LED current zoomed
2ns/div
1A peak
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 16
Linearity test - preliminaryQRLED linearity
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
0.0 1.0 2.0 3.0 4.0 5.0 6.0
V control
AD
C s
ign
al
SiPM
PMT
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 17
Conclusion
• Inductor has been changed from loop to toroidal structure
better magnetic isolation• 2 scenarios for calibration system
– QRLed driver at HEB (endcap) fibers needed– QRLed driver in detector on HBU no fibers
• At the next HCAL DESY meeting we would like to start the discussion about the integration
• It is a part of the EUDET task Multichannel LED calibration prototype
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 18
Backup slides
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 19
LED current• View of the LED
pulse for a middle amplitude (1.0 A)
• Measured with 1GHz voltage differential probe and 1GHz scope TDS4104 at 1Ω smd resistor
• 4ns/div 0.5A/div
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 20
In wider time scale
PIN
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 21
ECFA, JUN10, 2008 Ivo Polak, IPASCR, Prague 22
In wider time scale, increase of the amplitude
PIN 2mV/div