Atkin, E

Chernikov, V A

Goldsher, A

Kondratenko, S

Mishin, Yu

Pleshko, A

Volkov, Yu

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DEVELOPMENT OF THE PRINTED CIRCUIT UNITS FOR MILTIWIRECHAMBERSE.Atkin, S.Kondratenko, Yu.Mishin, A.Pleshko, Yu.Volkov,Moscow Engineering Physics InstituteA.Goldsher, Research Institute "Pulsar", MoscowV.Chernikov, Research Institute "Pulse Technique", Moscowe-mail: atkin@eldep.mephi.ruAbstractThe paper considers finished 16-channel printedcircuit units (PCUs), intended to read out and processpreliminary the signals of multiwire chambers. Theircharacteristics reflect the trends in mount density increase(up to 1 front-end channel per 1 cm.cub.).The PCUs are built with 8-channel ICs ofamplifier-shapers and discriminators based on applicationspecific semicustom arrays.The considered units are implemented with 4-layer PCBs measuring 90*40 mm.sq, which may besimply combined into a 32-channel unit. ICs and othercomponents are mounted by surface mount technology. The basic electrical characteristics of PCUs andICs are presented.1. INTRODUCTIONThe designers of the systems of radiation detectorsignal acquisition face the problem of reducing unitdimensions at channel number increasing. Its solutionconsists in the improvement of both the design of thePCB itself and the one of the front-end ICs, which mustcontain a greater number of channels .Further (see p.3) there are considered finished16-channel printed circuit units (PCUs), intended to readout and process preliminary the signals of multiwirechambers. The given units are a development of the PCUspresented at the 3-rd and 4-th Workshops [1,2]. ThePCUs are built with 8-channel ICs of amplifier-shapersand discriminators based on application specificsemicustom array. These ICs are described in thefollowing section.2. 8-CHANNEL ICs OF AMPLIFIER-SHAPERS AND DISCRIMINATORSThe structural diagram of a single channel ispresented in fig.1. It contains a preamp with differentialinput, main amplifier-shaper, base line restorer (BLR),comparator and output driver. On the basis of one and thesame application specific semicustom array (ASSA),manufactured by an npn bipolar technology with unity-gain frequencies above 6 GHz (at collector current 1 mA),there have been manufactured two eight-channel ICs, onecontaining amplifier-shapers and the other – thesubsequent units of the channel.In fig.2 the simplified schematics of theamplifier-shaper is shown. The schematics of thesubsequent channel part was considered earlier in [3].Standard input dynamic range makes up 5…200uA. The discriminator (high-speed comparator) outputsprovide a quasidifferential output in the GTL standard.The rest of the channel’s electrical characteristics arepresented in the table below .Transresistance, kOhm 25Input resistance, Ohm 330Shaper output rise time, ns 10Output pulse duration at base level, ns 50Shaper output full swing, V 2,5Range of comparator threshold setting, mV 10..2000Comparator rise time at C load = 5pF, ns 3Comparator fall time at C load = 5pF, ns 5Comparator propagation delay, ns 8Power consumption per channel, mW 40Supply voltage, V ±3Fig. 1. The  structural  diagram of  a  single  channelsymZIn Out1Out2Mainamplifier-shaperPreamp ComparatorOutputdriverBase linerestorerFig. 2. The simplified schematics of the amplifier-shaperThe features of the ICs are first of all the largemaximal output amplitude of the amplifier-shaper (notless than 2.5 V), allowing to use the amplifier-comparatorchannel not only for timing signal generation, but also tostore and process amplitude information. Moreover, at astandard dynamic range of 100 (from noise and up to themaximal amplitude) this allows to operate with highercomparator thresholds and thereby reduce problems withpick-up and cross-talk in a multichannel system.3. PRINTED CIRCUIT UNITSThe considered units are implemented with 4-layerPCBs measuring 90*40 mm.sq. ICs and othercomponents are mounted by surface mount technology.The unit is connected with the detector by four 10-pinFPC connectors Harwin F10. At the unit`s output a 40-pinHirose connector with a pitch of 1.27 mm is used.Two modifications of the PCU (lower oneUP25411L  and  upper  one  UP25411U),  capable  to   bejoined in a bookstand manner, forming a 32-channel unit,have been manufactured. The mount density increasesthereat up to the value of 1 front-end channel per 1cm.cub.The general view of the PCUs is presented in fig.3. At present a new modification of the ICs is prepared,having a greater input sensitivity (gain of preamp).The work is supported by the InternationalScience and Technology Center (ISTC).4. REFERENCES1. E.Atkin , Yu.Volkov, I. Ilyushchenko, S.Kondratenko,Yu. Mishin, P.Khlopkov, V.Chernikov, V.Subbotin,S.Tsvetkov,- Eight-channel PCBs for wire trackingdetectors . Proceedings of the Third Workshop onElectronics, for LHC Experiments, London, Sept.1997,463-465.2. E.Atkin, Yu.Volkov, S.Kondratenko, Yu.Mishin,A.Pleshko, 16-channel PCUs for processing signals ofmultiwire chambers. A functionally oriented semicustomarray. Proceedings of the Fourth Workshop on Electronicsfor LHC Experiments, Rome, September 21-25, 1998,CERN/LHCC/98-36, 30 October 1998,  p. 555-559.3. E.Atkin, I.Iljushenko, P.Khlopkov, S.Kondratenko,E.Kuprianov, Yu.Mishin, A.Pleshko, D.Savelyev,Yu.Volkov, V.Zhukov. Discriminator ICs for trackingand time-of-flight detectors. Same as previous,  p. 550-554.Fig. 3. The  photo  of  UP25411  PCUs  (-L and –U  modifications)InOut+-Zsym

Development of the Printed Circuit Units for Multiwire Chambers

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