View on the TOT option for CBM-XYTER (toward specs) E. Atkin, I.Ilyushchenko, A.Kluev, Yu.Volkov,...
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Transcript of View on the TOT option for CBM-XYTER (toward specs) E. Atkin, I.Ilyushchenko, A.Kluev, Yu.Volkov,...
View on the TOT option for CBM-XYTER (toward specs)
E. Atkin, I.Ilyushchenko, A.Kluev, Yu.Volkov, MEPhI
A.Voronin, SINP MSU
13rd CBM Collaboration meeting, FEE section, 12.03.09 1
Aim
To present a status view of joint team (MEPhI/SINP MSU) on the CBM-XYTER FEE specs, relevant to TOT option
13rd CBM Collaboration meeting, FEE section, 12.03.09 2
Outline13rd CBM Collaboration meeting, FEE section, 12.03.09 3
• Starting points are:- CBM XYTER wiki - internet- some experience
• Signal shape & equivalent circuit => DR• TOT option for CBM-XYTER.• Jitter. Transient noise view.• Statement of other problems• Two versions of data-driven architecture• On the way tasks & conclusions
Current pulses in strip detectors13rd CBM Collaboration meeting, FEE section, 12.03.09 4
The duration of the electron and hole pulses is determined by the time required to traverse the detector as in a parallel-plate detector, but the
shapes are very different.H. Spieler . Front-End Electronics Systems for Particle Detection and Imaging – Signal Formation and Acquisition. 2008 IEEE Nuclear Science Symposium, p.8
Equivalent detector ckt. simplified(toward lumped model)
13rd CBM Collaboration meeting, FEE section, 12.03.09 5
… accurate matching with FEE via quality microcables (up to tens cm in length) needed
CBM strips are not micro, but long transmission lines
Signal dynamic range (SDD=2)13rd CBM Collaboration meeting, FEE section, 12.03.09 6
2 mips
1 mipThreshold
Transient noise
Effectivness improvement
How many ADC bits needed?13rd CBM Collaboration meeting, FEE section, 12.03.09 7
Threshold/base line noise
(4÷6):11:(0.7÷0.8)typ
From threshold (read LSB) to 2 mips (7.2 fC max) we should foresee 4-bit range
~ 70..80% part of cluster goes to strip
Part of noisy 1 mip/thresholdLSB
(?):1
We have quite rigit specs on the noise accurate filtering needed
Other factors related to signal shape and amplitude
(?):1
Very front-end tasks13rd CBM Collaboration meeting, FEE section, 12.03.09 8
• Statistics of detector signals
• Detector should be considered as a RF structure – long transmission line
• Strips-FEE cabling (up to tens cm length) also looks like a transmission line which makes a delay and change a pulse shape
• Radiation hard environment
What does the TOT option mean for CBM-XYTER?
13rd CBM Collaboration meeting, FEE section, 12.03.09 9
TOT methodically is a type of ADC and similar to Wilkinson (dual slope) one
Pulse measurement process in Wilkinson ADC:
Three possible solutions for TOT 13rd CBM Collaboration meeting, FEE section, 12.03.09 11
Single slope TOT uses capacitor, charging by constant current source till the crossing of the signal falling edge
Direct TOT uses leading/falling edge comparator for time references
Schmidt trigger TOT (due to built-in hysteresis) uses lower threshold for the trailing edge triggering
Jitter (transient noise example)13rd CBM Collaboration meeting, FEE section, 12.03.09 12
Transient noise
Statement of other problems13rd CBM Collaboration meeting, FEE section, 12.03.09 13
• Balistic deficit • Double sided read-out• Leakage current (DC mode)
compensation versus noise • Type of shaping (CR-RCn and anti-
tail/anti-alias) both for amplitude measurements and timing
• Discriminator options (LE, CFD, ID) for timing
• Discriminator charge sensitivity• All versus long-term radiation • All versus power consumption
Dete
ctor
sig
nal fa
mily
sim
ula
tion
s n
eed
ed
Two versions of data-driven architecture
13rd CBM Collaboration meeting, FEE section, 12.03.09 14
Back-up architecture with cross-point switch is advantageous since it allows to perform a peak find function after derandomisation and therefore save power consumptionNow the derandomiser chip based on 12816 cross-point switch under development (A.Kluev). Pipeline ADC (Yu.Bocharov/A.Simakov) is expected to be one of the built-in block TOT study will trend us to incorporate front-end test structures. Prototyping late 2009.. beg. 2010
Mainstream solution is token-ring derandomisation
On the way tasks13rd CBM Collaboration meeting, FEE section, 12.03.09 15
- Direct agreements with Cadence and MG have signed for the next two years
- Europractice membership & DKs updated
- Expected are that 3 new PhD students for FEE development will be involved in the CBM FEE activity for 3 years starting from May 2009
- Other
Some references13rd CBM Collaboration meeting, FEE section, 12.03.09 16
1. S. Godowsky, M. Turala, et al. Pulse shapes of silicon strip detectors as a diagnostic tool. NIM A, 1993, Volume 326, Issue 1-2, pp. 239-242.
2. P. Allport. Silicon strip detector designs for the ATLAS experiment. NIM A, vol. 386, 1997 pp. 109–116.
3. R. Kollipara, A. Arodzero, J. Brau et al. Study of 18-cm long single-sided AC-coupled silicon microstrip detectors IEEE Trans. on NS, Vol. 42, Issue 2, April 1995 , pp.92 – 101.
4. H. Spieler . Front-End Electronics Systems for Particle Detection and Imaging . Signal Formation and Acquisition. IEEE Nuclear Science Symposium, Dresden, 2008, p.8.
5. F. Goulding, D. Landis, Ballistic deficit correction in semiconductor detector spectrometers, IEEE Trans. on NS, vol. 35, issue 1, 1988, pp. 119-124.
6. Dušan Kollár, Pulse processing and Analyses, DNP, FMFI UK Bratislava, www.dnp.fmph.uniba.sk/~kollar/je_w/el3.htm#5b
Some conclusions13rd CBM Collaboration meeting, FEE section, 12.03.09 17
- TOT option should be considered as an ADC block
- For amplitude measurements 4-5 bit (6 bit?) resolution ADC needed at lowest power consumption
- Filtering is to be studied versus jitter and time walk taking into account other system problems
- Different ways for power consumption minimizing is to be studied both at the block and architecture (system) level
- Detector signal family (for both sides) is to be studied as well as multichannel equivalent circuits