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IFR barrel upgrade:status of LST option
Roberto Calabrese
Ferrara University
10/18/2002
Outline General Overview
Standard LST Modified LST for BaBar
Issues Safety Reliability Radiation tolerance Mechanics (detector assembling, location of electronics) Electronics Manpower Cost
Status of R&D Schedule
Standard Limited Streamer Tube
Coverless version doesn’t have this PVC cover
Coverless PST chamber and E-field lines
A survey of large LST systemssystem date size
1 UA1 (upgraded muon system)
1985 0.90.9cm tubes covered 800m2 area, first large PST system used in HEP accelerator experiment.
2 NUSEX(Mt. Blanc Lab) 1986 43,000 tubes (0.90.9cm3.5m), 1,500m2.
3 CHARM II (CERN SPS) 1986 155,232 tubes (0.90.9cm3.75m), 5,820m2.
4 LVD (Gran Sasso Lab) 1988 120,000 tubes (0.90.9cm6.3m), 7,560m2. (constructed by SCARF, Houston-Northeastern)
5 ALEPH (LEP, CERN) 1990 8000 8-cell profiles (0.90.9cm7m) for barrel, ?? for end caps of hadron calorimeter.
6 DELPHI (LEP, CERN) 1990 20,000 tubes for hadron calorimeter.
7 OPAL (LEP, CERN) 1990 3482 8-cell, 900 7-cell, 3 - 7.3m long for barrel. 2304 8-cell, 0.5-2.2m long for endcap. Total 52,588 cells.
8 SLD (SLAC) 1990 10,000 8-cell modules, length varying from 1.9 to 8.6m. Covered 4500m2.
9 ZEUS barrel and rear muon detector (HERA)
1993 3600 PST with length varying from 0.7m to 10.2m. Covered 2,000m2. Noryl instead of PVC for better wire aging and less safety hazard in case of fire.
10 MACRO 1993 2.9cm2.7cm12m big size tubes. 6 supermodules, 5856 tubes/supermodule.
11 COMPASS muon wall detector
1999 1200 PST tubes
12 SMC (Spin Muon experiment at CERN)
1999 768 8-cell, 4m long chambers. Total 6144 cells.
Covered 245m2. (Constructed by SCARF, Houston-Northeastern)
13 WA98 (SPS, CERN) 1999 2 planes, each contains 19 8-cell, 1.2m long chambers. (earlier generation WA80,WA93 used PST too)
14 PHENIX muon identifier
1999 14000 8X0.9cm0.9cm(5.2 or 2.5)m tubes.
LST efficiency 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.
Test (Princeton) on the 10-chamber array with HV = 5000V, Ar/C4H10(25/75)
89.5% 90.7% 88.5% 86.4%
90.2% 93.8% 91.8% 90.5%
86.8% 92.1% 92.6% 90.2%
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
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
Possibilities to improve efficiency
Option 3: modified double-layer with a small cell (9x8mm)
Readout of x and y coordinates from outside strips
Efficiencyimprovement
Minimum path length (mm)
Comparison of induced signals in different configurations
Single layer
Double layers, back to back
Single layer with a same thickness wood spacer
Test results
Ratio(double/single) = 0.134/0.207 = 65%
Ratio(spacer/single) = 0.094/0.207 = 45%
Test with single-layer with a same thickness wooden spacer
What we can say now
Double-layer configuration smears position resolution, but this can be better than 0.5 cm
We will be able to use existing FEC if we use a preamplifier with a gain 15
Issues
Safety Radiation tolerance Reliability Mechanics (detector assembling, location of electronics) Electronics Manpower Cost
Safety
Safe gas mixture, like Ar/Iso/CO2 (2.5/9.5/88) (SLD)
Use Noryl instead of PVC: no clorine in the material
Radiation tolerance: PVC vs Noryl
From Zeus experience, Noryl tubes have much better radiation resistance Wire after 100mC/cm,
PVC tube
Wire after 100mC/cm,Noryl tube
Radiation tolerance
The expected integrated charge until 2010 for the Barrel Inner Layer is about 5mC/cm (J.Va’vra), of the same order as in Zeus, so no radiation problem is expected, but we need to build Noryl tubes.
Reliability Initial mortality
Based on past experience (Zeus, Phenix), can be kept to a reasonable value (few %) with quality control during the production, and burn-in test before installation. Depend (also) on tube length.
Phenix QC procedure (http://www.phenix.bnl.gov/WWW/muon/muid/muid/accept.html)
only about 20 wires (over 56000) dead as initial mortality
Long term failure rate 1% in 6 years (Zeus) Less than 5% in 10 years (LEP experiments) 4%(endcap), up to 11%(barrel) in 10 years in SLD
(11% mainly due to mechanical problems during installation)
Mechanics
A detailed study of all aspect of mechanics has to be done: Every chamber must fit in the 22 mm available space Detector assembly and installation Location of FE electronics Routing of cables
A working committee has been setup, which includes mechanical engineers from Princeton (Bill Sands, Richard Fernholz) and Ferrara (Vito Carassiti)
Electronics
Different options under study, depending on the use of existing FEC
Aims: Use as much of present RPC electronics as possible,
allowing for smaller chamber pulse. Fit all FE electronics in “accessible” location (not behind
iron slabs) Cost evaluation for December Coll. Meeting
(preliminary estimation for November?)
Front End for the BaBar IFR upgrade:option 1 (Angelo Cotta Ramusino)
Each strip is equipped with a front end preamplifier realized with
Components-Off-The-Shelf (COTS).
The preamplifiers will have fixed gain.
The preamplifiers will have differential outputs and
will drive the output signals on micro-ribbon twisted pair cables.
The differential signals will be handled by COTS-based differential receivers; these may be equipped with a step-programmable gain stage
The single ended output from the receiver cards is then fed to the FECs, all relocated into minicrates outside the iron
IRO
N
Front End for the BaBar IFR upgrade:option 2 (Angelo Cotta Ramusino)
Each strip is equipped with a front end preamplifier based on one of the various amplifier/discriminator ASICs designed for HEP applications
The dynamic of the IFR detector must be matched to the ASIC’s one (by means of a passive network ahead of it)
A new programmable module, ICB-like, must provide the threshold voltage for the front end ASIC
The ASIC will drive the output signals (LVDS level) on micro-ribbon twisted pair cables.
The ASICs outputs will be handled by LVDS differential receivers whose single ended output is then fed to modified FEC (skip the preamplifier
stage) all relocated into minicrates outside the iron
IRO
N
Front End for the BaBar IFR upgrade:option 3 (Angelo Cotta Ramusino)
Each strip is equipped with a front end preamplifier based on one of the various amplifier/discriminator ASICs designed for HEP applications, with a passive adaptor to match
its dynamic range to the IFR detectors’ one.
The LVDS signals are locally converted to single ended LV-TTL and fed to a Field Programmable Gate Array (FPGA) which implements the storage and readout functions now
performed by the monostables and the shift register of the FEC
The ICB must provide the threshold voltage for the front end ASIC as well as the BaBar High Speed Clock needed by the FPGA. (not needed if the serial readout clock from the IFB is continuous because the FPGA can then recover a 4x clock from it by means of an internal
PLL circuitry).
One FPGA could replace one or more FECs
Only the power and the serial CLOCK, SHIFT/LOAD and DATA lines must cross the iron boundary.
COST and RADIATION HARDNESS are under evaluation.
IRO
N
Front End for the BaBar IFR upgrade: option 3Storage and output section of FPGA
16x INPUT STRETCHER
Dual Port RAM1024 * 16bit
WritePtr
ReadPtr
OR 64
Shif
t R
egis
ter
64x
1us
win
dow
~16u
s ra
nge
11us
late
ncy
OR 64
Shif
t R
egis
ter
64x
Shift/LoadCk_Chain
Data OutSHIFT REGISTER
16 x
Manpower
At present: USA: Princeton Univ., Ohio State Univ.? INFN: Ferrara, Padova, other IFR groups
Include more institutions to reach a reasonable size for the system ( especially needed for the installation, commissioning, operation)
Cost
13 planes with double-layer tubes Cost about 510 K$
10 planes with single-layer tubes + 3 planes with double-layer tubes Cost about 340 KS
We are working on a better estimate
Future R&D
16 tubes (options 2 and 3) have been ordered to Pol.Hi.Tec. Test different configurations Test with safe gas mixture Test with BaBar IFR electronics
Tubes at Pol.Hi.Tech.
View of the
HV decoupling
circuit
Tubes at Pol.Hi.Tech.
View of the
double layer
end-cap
Pol.Hi.Tech.
Large assembly
hall available
Schedule
Jan.15, 2003 Decision Apr.15, 2003 Order Jul.15, 2003 1st tube Aug.15, 2003 Start assembling Jan.15, 2004 Last tube Jul.1, 2004 Start of installation of 2 sextants
Time scale for addressing issues Nov. 15, 2002
Preliminary results with double-layer prototypes Preliminary estimation of electronic cost
Dec. 14, 2002 Preliminary results with full size (4m) double-layer prototypes Preliminary results of aging test (10mC/cm) Conceptual design for assembling into modules Conceptual design for installation Decision on electronic options Preliminary results of MC simulation with a real detector Definition of QC procedure