1. SPIROC Status : Last developments for SPIROC
Stéphane Callier, Selma Conforti di Lorenzo, Frédéric Dulucq, Gisèle Martin-Chassard, Christophe de La Taille, Ludovic Raux, Nathalie Seguin-Moreau
IN2P3/OMEGA-LAL Orsay
France

2. Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg
« Building block »
Submission of a “Building block” to test and validate new structure for SPIROC
4-Channel ASIC
New features:
New preamplifier structure based on NMOS input transistor to be less sensitive to coherent noise
Preamplifier gain tunable independently on 8 bits (minimum capacitance 6.25 fF)
Discriminator connected directly to preamp => No fast shaper => power saved
If OK, could be used in “SPIROC 3” or in “SPIROC 2c”
Submission in May 2011
Delivery in October 2011
IN2P3 Funding
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

3. Analogue signals HG Preamplifier: Gain = 32mV/pe Noise RMS = 1mV
Out_SSH_LG
100 pe (16 pC) ; Cf = 200fF
Out_PA_HG
1 pe (160 fC) ; Cf = 200fF
HG Preamplifier:
Gain = 32mV/pe
Noise RMS = 1mV
SNR ~ 32
Out_SSH_HG
1 pe (160 fC) ; Cf = 200fF
HG Preamplifier + Slow shaper
Vmax= 46 mV/pe
Noise RMS = 2,3mV
SNR ~ 20
(Reminder: in SPIROC SNR~10)
Other important remarks:
No rate effect observed
Negligible cross-talk (<1%)
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

4. Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg
Preamplifier linearity vs Cf
Preamplifier gain tunable independently on 8 bits (minimum capacitance 6.25 fF)
1/Vout vs Cf
Nice linearity observed => possibility to adjust the gain channel by channel for HG and LG
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

5. Charge measurement linearity
SSH_HG_Cf=200fF(PA_gain=100)
Dynamic: up to 5pC (~ 30pe)
SSH_HG_Cf=1pF(PA_gain=20)
Dynamic: up to 16pC (~100pe)
SSH_LG_Cf=200fF(PA_gain=5)
Dynamic: up to 80pC (~500pe)
SSH_LG_Cf=1pF(PA_gain=1)
Dynamic: up to 300pC (~1875pe)
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

6. Trigger efficiency 50% trigger efficiency charge vs threshold (Volts)
Trigger capability is down to 1/2pe (~ 80 fC) (Reminder: Trigger efficiency is down to 1/3 pe in SPIROC)
The expected 5σ (~ 30 fC) cannot be reached due to a internal coupling via the substrate
This coupling is understood and could be easily corrected in the future
50% trigger efficiency charge vs threshold (Volts)
S-curves for different injected charges (Trigger efficiency vs threshold (DAC units)
1pe (160 fC)
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

7. Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg
EASIROC (ex-SPIROC 0)
EASIROC1a -> ”light” version of SPIROC
conservative version of EASIROC
EASIROC/SPIROC x bugs corrected
Corrected « rate dependency »
Switches for Cp capacitances removed
Cp=1pF for HG
Cp=3pF for LG
Corrected cross-talk HG/LG
Default slow control setup extended
Right value for bias resistances implemented (ibm_pa_lg, ibmin_pa)
Submitted on the 2th September 2011
Delivery within few days
Should validate the correction of the two major problems on the preamps (« rate dependency » and cross-talk HG/LG)
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

8. Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg
Conclusion
New preamp structure tested in the “building block”
First measurements seem OK (Signal-to-noise ratio, linearity, trigger efficiency, etc.)
Further measurements have to be performed to validate it completely
Main advantages of this structure:
Should be less sensitive to coherent noise
No fast shaper => power saved
This new preamp is a serious candidate and it could equip a next release of SPIROC
Major bugs are understood in SPIROC 2b:
« Rate dependency » and HG/LG cross-talk
The bugs comprehension should be validated before the end of the year with “EASIROC1a”
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

9. Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg
Backup slides
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

10. Our plans for 2012-2013 : SPIROC 2c
New Chip “SPIROC 2c” submission expected in February 2012
Pin-to-pin compatible with “SPIROC 2b”
Intermediate chip before SPIROC 3 to validate number of points
1 major improvement:
Preamplifier: 3 options :
Corrected SPIROC 1 and 2 preamplifier (“Rate dependency”, HG/LG cross-talk)
New preamp tested in “building block”
Other minor modifications, corrections or improvements
Bandgap, delay box, latch on auto-gain discriminator, 4-bit DAC, etc.
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg

11. Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg
Our plans for : SPIROC 3
New Chip “SPIROC 3” submission expected in 2012 or in 2013 depending on the submission of a “SPIROC 2c” version
AIDA funding
5 major improvements:
Preamplifier: 3 options :
Corrected SPIROC 1 and 2 preamplifier (“Rate dependency”, HG/LG cross-talk)
New preamp tested in “building block”
“Klaus 2” preamplifier
New SCA management => real “zero suppress”
Channel managed independently -> Implied new digital part (see Frédéric’ talk)
SCA Depth will be reduced (from 16 to 8)
New TDC => avoid dead time
Already existed and tested in PARISROC 2
Slow control by I2C:
Developed in collaboration with IPNL
Possibility to have a “circular memory mode”
Other minor modifications, corrections or improvements
Bandgap, delay box, latch on auto-gain discriminator, 4-bit DAC, Slow control cells, etc.
samedi 24 novembre 2018
Ludovic Raux – SPIROC Status – AHCAL meeting, DESY, Hamburg