Harbin Institute of Technology, China Prof. Y. HU,1,July, 2014,Design Example,LHC-CMS (Compact Muon Solenoid) experiment in CERN: Diameter: 15 m Length: 21.6 m Detection of impact proton-proton,Harbin Institute of Technology, China Prof. Y. HU,2,July, 2014,Large Hadron Collider Experiences,Harbin Institute of Technology, China Prof. Y. HU,3,July, 2014,Proton-Proton Collision,p+,p-,Harbin Institute of Technology, China Prof. Y. HU,4,July, 2014,Electron-Positron Collision,e+e collision WW , ZZ , ZH , etc ?,Harbin Institute of Technology, China Prof. Y. HU,5,July, 2014,Silicon Microstrip detectors,Operating principle: Detector thickness 300 mm Inter-strip spacing 25 mm Strip length 10 mm Strip width 60 mm CDET = 10 pF/strip,insulant SiO2,Harbin Institute of Technology, China Prof. Y. HU,6,July, 2014,Equivalent Scheme,Charge collection for each strip: Total electrical charges: Mean current: 700 nA Equivalent scheme,Harbin Institute of Technology, China Prof. Y. HU,7,July, 2014,Electronics Readout,Schematic diagram:,Analog memory and processor,discriminator and memory,Harbin Institute of Technology, China Prof. Y. HU,8,July, 2014,Pre-amplifier Topologies,Main characteristics: Low noise High speed Low power consumption,Harbin Institute of Technology, China Prof. Y. HU,9,July, 2014,Pre-amplifiers Noise Performance,Charge amplifiers: Transimpedance amplifiers:,Cf,Cin,Cdet,idet,vout,vout,Harbin Institute of Technology, China Prof. Y. HU,10,July, 2014,Pre-amplifiers performances,Charge amplifiers: Low noise level Low operating speed Transimpedance amplifiers: High noise level Rapid operating speed,Harbin Institute of Technology, China Prof. Y. HU,11,July, 2014,Pile-up Phenomenon,The pile-up phenomenon is observed by a saturation of pre-amplifier Need a shaper,Harbin Institute of Technology, China Prof. Y. HU,12,July, 2014,Shapers characteristics,The bandwidth is optimised to increase the ratio S/N of electronics readout. Return rapidly to zero in order to avoid the pile-up phenomenon. To have a large platform in order to detect a reliable maximum,Harbin Institute of Technology, China Prof. Y. HU,13,July, 2014,Semi-Gaussian Filters (CR-RCn),Transfer function: Output for a step input: Shaping time or peaking time,Harbin Institute of Technology, China Prof. Y. HU,14,July, 2014,Noise Optimisation for Capacitive readout system (charge amplifier + shaper amplifier),Conversion gain (charge to voltage) in the charge amplifier:,Voltage gain in the shaper amplifier at t = t:,Harbin Institute of Technology, China Prof. Y. HU,15,July, 2014,Output Noise Calculation,Harbin Institute of Technology, China Prof. Y. HU,16,July, 2014,Equivalent Noise Charge (ENC) at Input (1),ENC due to channel thermal noise: ENCd total noise at output: ENCd at input: Noise optimization : Optimal noise matching between source capacitance and transistor input capacitance Use of pulse shapers with large peaking time ts,Ct: total capacitance at the input node.,B(x,y): the Beta-function, ts = nt: the peaking time of S-G pulse shaper,Harbin Institute of Technology, China Prof. Y. HU,17,July, 2014,Equivalent Noise Charge (ENC) at Input (2),ENC due to channel 1/f noise: ENCf total noise at output: ENCf at input: Noise optimization : Optimal noise matching between source capacitance and transistor input capacitance ENC is totally independent to the peaking time ts. (not to shaper amplifier),Harbin Institute of Technology, China Prof. Y. HU,18,July, 2014,Equivalent Noise Charge (ENC) at Input (3),ENC due to shot noise of detector: ENCS total noise at output: ENCs at input: Noise optimization : ENC is proportional to the peaking time of the shaper amplifier. ENC is totally independent to the charge amplifier.,The detectors shot noise:,Harbin Institute of Technology, China Prof. Y. HU,19,July, 2014,Equivalent Noise Charge (ENC) at Input (4),Total ENC of the readout system: Determination of the design parameters: A five dimensional optimisation problem, no analytical solution (W, L, ID, ts, n) Optimal input noise matching conditions for charge sensitive amplifier Optimal peaking time and order n of the pulse shaper,Harbin Institute of Technology, China Prof. Y. HU,20,July, 2014,Optimisation of Noise Performance,Optimisation of noise performance in charge amplifier Each ENC is optimised individually. Determination of input transistor dimension and DC bias conditions Optimisation of total ENCT with shaper amplfier,Harbin Institute of Technology, China Prof. Y. HU,21,July, 2014,Input Noise Matching Conditions (1),To minimise thermal noise ENCd: Minimal channel length for input transistor Large DC bias current Optimum width: Minimal ENCd-min:,Harbin Institute of Technology, China Prof. Y. HU,22,July, 2014,Input Noise Matching Conditions (2),To minimise 1/f noise ENCf: taking into account the ENCd due to the channel thermal noise