Proposal for LST-based IFR barrel upgrade

1. Proposal for LST-basedIFR barrel upgrade Roberto Calabrese Ferrara University Workshop on IFR replacement, SLAC, 11/14/2002

2. Outline • General Overview • Layout geometry • Performance • Readout methodology • Electronics • Gas, HV, DAQ • Costs • Other presentations

3. General overview • The entire project is driven by the allowed space • The intrinsic efficiency of a standard LST tube is about 90%. • This is due to dead spaces in the LST tubes. • Efficiency is too low for our purposes. Not enough space to put 2 standard layers.

4. Possibilities to improve efficiency(given the allowed space) • Option 1: single-layer with a large cell (19x17 mm) Readout of x and y coordinates from outside strips

5. Possibilities to improve efficiency • Option 2: double-layer with a small cell (9x8mm) Readout of x coordinate from wire and y coordinate from outside strips

6. Possibilities to improve efficiency • Option 3: modified double-layer with a small cell (9x8mm) Readout of x and y coordinates from outside strips

7. Detector layout: segmentation of a detector layer Z strip signal collection PCB PCB for cable connectors Z strip signal collection PCB Z strip readout Layer of LST Ф strip readout Ф strip signal collection PCB (a similar one in the opposite corner) PCB for cable connectors Servizio Elettronico INFN Ferrara

8. Detector layout: details of strip signal collection PCB Servizio Meccanico INFN Ferrara

9. Performance • Expected efficiency about 96% • Position resolution better than 3 mm (z) for standard LST better than 9 mm () We do not need such a resolution and we can increase the strip width, thus decreasing the number of channels (  MC simulation)

10. Detector layout: questions • How many strips? • resolution, cost, space • How many chambers/layer ? • installation, cost

11. Detector layout: answer to the questions • We are considering 4 cm z-strips and 4.3 cm -strips (2 -strips (along the wire)/LST tube) • 96 z-strips for each layer, total 6912 z-strips • 74 -stripsfor the outer layer, total 4572 -strips • About 11500 channels of electronics • 2 chambers/layer (remove only one corner block at the time), but the number of z-stripsdoubles (more cables, but same number of electronics channels) or we need to decouple z-strips from the chambers

12. Readout methodology • Only digital readout of strips • Time measurements could be implemented: • OR of 16 discriminated pulses • Time resolution about 16 ns ( using BaBar reference clock) • Implemented with FPGA

13. Electronics • FEC gain depends on the shape of the signal  FEC ampli cannot be used • Existing FEC: to be modified if we want to use them (when?)  the baseline is to use new electronics

14. Front end module design : block diagram of the NEW 96 channel (1 view of 1 layer) FEC Threshold 96x Amplifier-Discriminator Cost per channel inclusive of: -components -PCB -crate&power supply 10 € / channel Servizio Elettronico INFN Ferrara 12us Digital OneShot 11us Digital OneShot 12us Digital OneShot 11us Digital OneShot 96 x 6 x Shift/Load Data Out 6 x Ck_Chain SHIFT REGISTER 6 x Shift/Load To the Active Patch Panel ahead of the FIFO Board Implemented in a single high performance FPGA (Field Programmable Gate Array)

15. Front end module design : schematic of the front end based on Off-The-Shelf components Power dissipation: 250mW Servizio Elettronico INFN Ferrara

16. Front end module design : analog simulations, effect of strip capacitance and impedance b) a) Simulation of the amplifier/discriminator output from a 4pC input signal (0.1mA * 40ns) Comparator threshold = 50mV dielectric thickness 0.75mm a) dielectric FOAM (εr=1) b) dielectric PTE (εr=3.3) c) dielectric FR4 (εr=4.8) c) Servizio Elettronico INFN Ferrara

17. Gas system • mass flow control system • main gas transport pipe system (existing) • final gas distribution and bubbling system. We assume all the tubes in a layer with a single in/out • Safe gas mixture, like Ar/Iso/CO2 (2.5/9.5/88) (SLD)

18. HV, DAQ • Each tube has a separate HV connection ( 2 for a double layer tube) • Possibility to use a commercial HV system for LST available from CAEN (SY546 mainframe + 12 channel boards A548), 150 $/channel • DAQ • No change, all signals are FEC-like

19. Costs: assumptions • double layer LST with 8mm cells; each layer with a separate HV; each ground returning separately through a measuring resistor • 96 strips (40 mm strips) in the z direction; 2 strips per LST in the  direction • 2 chambers/layer (double the number of z strips signals) • 12 active layers

20. Costs (I) • Tubes: • 30 K$ (setup) • 450 K$ ( about 200 $/tube x 2280 double layer tubes) Total cost tubes 480K$ (using single layer tube this cost would be about 300K$) • Strip readout planes 240 m2/layer x 6 layers x 50 $/m2 = 72 K$ Signal collection (PCB’s) inside iron 18 K$ Total cost readout planes 90 K$ • Grand total chambers 570K$ (double layers); 390K$ (single layers)

21. Costs (II) • Total cost of signal flat cables 146 K$ (outside iron) 15 K$ (inside iron) • Total cost of signal flat cable connectors 28 K$ • Total cost of electronics 115 K$ • Service panels 4 K$ • Total cost of LV ground wire 5 K$ • Total cost of LV plugs 4K$ • TDC system 20K$ (optional) • Total electronics + cables 322 K$ (maximum); 171 K$ (minimum)

22. Costs (III) • Total cost of HV wire 23 K$ • Total cost of HV banana plugs 9 K$ • Total cost of HV power supply+distributors 170 K$ • Total cost of mass flow control system 11 K$ • Total cost bubbling system 4 K$ • DAQ, cooling no expected cost • Total this page 217 K$ • Grand total detector 780 K$ 1100 K$

23. Addressing the various issues • R&D issues and status Changguo Lu • LST experience and production issues Mario Posocco • Installation issues Livio Piemontese