Update on LST-based IFR barrel upgrade Roberto Calabrese Ferrara University Workshop on IFR replacement, SLAC, 12/8/2002

Addressing the various issues Installation issuesBill Sands R&D issues and statusChangguo Lu Schedule and conclusions Stew Smith

Outline IFR-LST design Modular detector construction Readout methodology Electronics Gas, HV Costs

IFR-LST design Option 1: modified double-layer with a small cell (9x8mm) Readout of x and y coordinates from outside strips

Option 2: single-layer with a large cell (19x17 mm) Readout of x and y coordinates from outside strips IFR-LST design

Detector layout We are considering 38.5 mm z-strips and 42.5 mm  -strips (2  -strips (along the wire)/LST tube)  96 z-strips for each layer, total 6912 z-strips  72  -strips for the outer layer, total 4074  -strips  channels of electronics Z-strips decoupled from the chambers Chambers made with 5-7 tubes

DETECTOR LAYOUT: EXPLODED Exploded view of the composite detector chamber. The stack of layers building up the PHI strip plane is also shown exploded. The signal PCB (darker green, horizontal) goes actually on top of a portion of the strip plane with exposed strips. Signal traces on this PCB run across the strips and bring the strip signals to a connector not show in the drawing. The inner ribs are 1mm thick, while the outer ribs are 0.5mm thick. The drawing is available at

DETECTOR LAYOUT: ASSEMBLED Partial view of a detector chamber made of 5 LSTs. The actual number of LSTs in a chamber, as well as the LST type (8 cells or 7 cells), varies to accommodate to the different widths of the iron gaps. The PHI strips run longitudinally. Their width is half the width of an 8 cell Iarocci tube. Their signals are brought to a PCB-mount connector, not shown here, accessible from the front. The LSTs are glued to the PHI strip plane. Carbon fiber (or steel) strips are also glued in between (some of) the LSTs of the unit, to increase the stiffness of the chamber. //

1.b Constructive details of the composite strip plane The composite strip plane is built as a stack of the following materials in foil: PET sheet, 190um thick 50um copper foil (glued to the PET above) machined into Z strips 37mm wide and 1.5mm apart PET sheet, 250um thick (It could have holes to reduce effective ε r ) FR4 sheet, 300um thick for stiffening 18um copper foil (glued to the PET below) PET sheet, 50um thick ALLOW 50um to 70um THICKNESS FOR GLUE AT INTERFACEs 1,2,3 Servizio elettronica INFN-FE Modular detector construction ~ 1mm Side facing the LSTs Side facing the iron 2 3 1

1.c Fabrication of Z and PHI strip planes The composite strip foils will be assembled in composite strip planes of two types: -the Z type with: - Plane length = detector layer’s length - Plane width= half the detector layer’s width, for easier shipping - Number of Z strips per plane: 96 - Single strip properties: width 36.5mm; interstrip spacing 2mm; impedance ~4  -the PHI type with: - Plane length = detector layer’s length - Plane width = width of LST chamber onto which it will be glued - Number of PHI strip per plane: twice the numer of LST in the module - Single strip properties: width 40.5mm; interstrip spacing 2mm; impedance ~3.5  The full size Z strip plane will have to be assembled at the USA assembly site. The PHI strip planes will be glued on top of their associated chambers at the USA assembly site Modular detector construction

IAROCCI TUBE TUBE MATERIAL : NORYL THE TUBE IS NOT SELF SUPPORTING 30

RIB RIB MATERIAL : STEEL NUMBER OF RIBS : TO BE OPTIMIZED DEPENDING ON DETECTOR’S EFFICIENCY AND STIFFNESS REQUIRED ASSUMING A RIB OF 1 MM THICK FOR EACH TUBE, THE TOTAL LENGTH NEEDED IS ABOUT 8000 m

DETECTOR’S STIFFNESS: THE HELP OF THE RIBS

GLUEING – PHASE 1 THE RIB IS GLUED ON THE TUBE’S SIDE

GLUEING – PHASE 2 THE DETECTOR’S MODULE IS ASSEMBLED

GLUEING – PHASE 3 STRIPS, GROUND, SIGNAL PCB AND INSULATOR FOILS ARE ASSEMBLED THE TOTAL THICKNESS IS ABOUT 1 MM

GLUEING – PHASE 4 STRIP PLANE IS GLUED ONTO THE TUBES

DETECTOR’S VERTICAL STIFFNESS

MOUNTING AND DISMOUNTING THE DETECTOR  THE Z-STRIP PLANE GOES IN TO THE GAP; A PROPER TOOLING KEEPS IT IN SHAPE AND PLACE  THE CHAMBERS OF THE DETECTOR ARE INSERTED ONE BY ONE FROM THE BOTTOM TO THE TOP, THE NEXT SLIDING ON THE PREVIOUS ONE  EACH CHAMBER CAN BE HELD ON BOTH EDGES, WHICH ALLOWS THE LIFTING AND THE ADJUSTMENT.  WHEN THE CORNER PIECES ARE MOUNTED THE DETECTOR DISASSEMBLY IS STILL POSSIBLE AFTER THE CENTER PIECES REMOVAL; THE PROCEDURE IS THE FOLLOWING: 1) LIFTING THE UPPER CHAMBERS 2) EXTRACT THE CENTRAL CHAMBERS  3) IN THE MIDDLE OF THE GAP THERE’S THE SPACE TO LOWER OR LIFT THE OTHER CHAMBERS AND REMOVE THEM.  THE OPERATION OF ASSEMBLY AND DISASSEMBLY NEED A TOOLING FOR HOLDING AND HANDLING THE CHAMBERS OF THE DETECTOR.

Installation of the Z strip plane unbounded to the LSTs The Z readout plane is installed first, as a whole, while the corner pieces are removed. It leans against the iron; the FR4 makes it rigid, so that it won’t fold. The Z strips are read out through connectors located at the backward end of the Z strip plane: in this way the connectors will not obstacle the insertion of the detector chambers from the forward end of the IFR Z IFR BACKWARD IFR FORWARD signal connectors

INSERTING THE Z-STRIP PLANE THE Z-STRIP PLANE SLIDES INTO THE GAP A TOOLING FOR HOLDING AND MOVING THE FOIL IS NEEDED

INSERTING THE DETECTOR - 1

INSERTING THE DETECTOR - 2

EXTRACTING THE DETECTOR

THE LAYER IN PLACE

Lowering the dead space The chambers will be built with different numbers of LST tubes. They will also use LSTs of different cell numbers to better fill the iron gaps: 8 cells Width: 84mm + 1mm ribs 7 cellsWidth: 74mm + 1mm ribs The drawings of the IFR iron allowed us to estimate the widths of the iron gaps for the layers that are to be equipped with detectors.

1.g1details of strip signal collection PCB and cabling Modular detector construction A A E D C B A)strip foil (190um PET foil facing DOWN) B)500um mono-layer PCB (on FR4) with holes, for soldering traces to strips, and signal traces running toward the connector C)200um mono-layer PCB (on FR4) : ground plane for signal traces: solid copper facing up D)composite insulating foil for the detector’s strips readout plane E)solid copper foil (50um PET, copper foil facing DOWN) d drawings by V. Carassiti:

1.g2details of strip signal collection PCB and cabling Modular detector construction The long PCB used to collect signals from the Z strips could be made in Kapton (which was quoted us 700Euro each) or could be home-made in 2 pieces of FR4 with signal traces obtained by machining the solid copper surface (100 Euro/m 2 ). The 2 pieces would have to be soldered together. Then they would have to be soldered to a third PCB that routes the signals to a suitable connector like the Robinson Nugent P50E-034P1-SR1-TG The shorter PCB used to collect signals from the PHI strips can be fabricated by the standard etching techniques. It also mounts the right angle PCB connector Robinson Nugent P50E-034P1-SR1-TG. The cable chosen is the Amphenol , “microribbon twist&flat” cable, with a 0.025” pitch, higly flame retardant and halogen free. It will be fitted with an header Robinson Nugent P25E-034S-TG. The cable cost is about 14 Euro/m. Around 200 such flat cables should fit into a 2” x 4” cable conduit

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

Front end electronics design: block diagram of the new 64 channel FEC 64x Amplifier-Discriminator 11us Digital OneShot Shift/Load Ck_Chain Data Out SHIFT REGISTER 64 x Threshold 12us Digital OneShot 11us Digital OneShot 12us Digital OneShot Shift/Load 4 x Implemented in a single high performance FPGA (Field Programmable Gate Array) from backplane to backplane from backplane 4 x input connectors for microribbon cable Estimated board power consumption: 16W A VHDL model of the logic architecture implemented in the FPGA is available ( link: )

Front end electronics design: Schematic of the front end based on Off-The- Shelf components Power dissipation: 250mW

Front end electronics design: analog simulations Simulation of the amplifier/discriminator output from a 4pC input signal (0.1mA * 40ns) Comparator threshold = 50mV dielectric thickness 0.75mm a) dielectric FOAM (ε r =1) b) dielectric PTE (ε r =3.3) c) dielectric FR4 (ε r =4.8) a) b) c)

Front end electronics design: structure of the 16-FEC crate The detector geometry outlined above produces a total of channels, divided over 786 cables (most of the ones in PHI not fully occupied) 786 / 64 = 12,28 crates Since the PHI cables are not fully occupied with signals we could gang together some of them, to better exploit the available resources. In the end 12 FE-CRATES, each hosting 16 FE cards, should be sufficient. Each crate hosts 16 NEW FECs. The 4 data output from each NEW FEC is transmitted, over the CRATE backplane, to the CRATE – IFB interface. This provides to the transmission of the 64 serial data streams toward one IFR FIFO BOARD. The CRATE – IFB also hosts: -one Clock fanout card: it receives and distributes the BaBar clock signal to the FPGAs -one DAC/ADC card with 16 outputs, to provide the threshold voltage to each NEW FE card independently.

Update on HV cables The HV cable is now defined: the KERPEN code is a 37 conductor HV cable, compliant to SLAC safety standards and particularly suited for this application, since, with the detector segmentation shown above, the number of HV channels required per layer reaches just the value of 37. We have then one cable per layer, 12 per sextant. Each cable has a cross section area of about 1.3cm 2 (1.3cm in diameter)

Gas system Mass flow control system. New mixing station in existing gas shack. Main gas transport pipe system. It should be possible to use existing pipes (spares). Final gas distribution and bubbling system. The current bubbler boxes can be reused. We assume all the tubes in a layer with a single in/out. Safe gas mixture, like Ar/Iso/CO 2 (2.5/9.5/88) (SLD)

Individual HV connectionsN.4152 HV distributed channelsN.1038 Worste case rate (2 Hz/cm 2 )Hz6400 Max chamber current AA 0.64 Typical rate (0.2 Hz/cm 2 )Hz640 Max chamber current AA 0.06 HV system Each chamber is connected through individual conductors up to the distribution crates. The HV system has to provide: Regulated HV up to 5 kV Current monitoring Overcurrent protection Number of channels and maximum current per channel:

These requirements are satisfied by CAEN SY546, a commercial system developed for the LVD experiment at the "Gran Sasso" laboratory. SY546 consists in a crate hosting 8 A548 HV boards. Each board has one HV regulated power supply which feeds 12 output channels. The current flowing in each distributed channel is individually monitored and alarm thresholds can be set for each of them. Electrical characteristics of the distributed channels: max. output voltagemax. output currentmonitoring resolution 6 kV5-10 µA5 nA The system can be interfaced to the Detector Control system via the usual CAENET-VME module already used in BaBar. HV system

Update on cost estimates: assumptions Double layer LST; 8 cells and 7 cells types; each layer with a separate HV 96 strip (36mm strips) in the Z direction; 2 strip per LST in the PHI direction Z strip plane installed and readout as a whole; readout from backward side of IFR Modular detector construction; readout from the forward side of the subdetectors 12 active layers An EXCEL spreadsheet is available to help determining the costs of the proposed apparatus, “ numerologia712.xls” ( link:

Update on cost estimates: assumptions Total number of 8-cell LSTs: 1866 Total number of 7-cell LSTs: 210 Total number of HV channels: 4152 Total number of Z strips : 6912 Total number of PHI strips : 4074 Total number of signals: Total number of microribbon flat cables: 786 Total number of FE CRATEs (16 NEW FE cards per CRATE): 12 Total number of NEW FE CARDS: 192 (12288 channels) Total area of Z /PHI strip plane [m²]:

Update on cost estimates Tubes:  30 K$ (setup)  405 K$ ( 195 $/tube x 2076 double layer tubes) Total cost tubes 435K$ (using single layer tube this cost would be about 300K$) Strip readout planes 215 m 2 /sextant x 6 sextant x 70 $/m 2 = 90 K$ Signal collection (PCB’s) inside iron 18 K$ Total cost readout planes 108 K$ Grand total chambers 543K$ (double layers); 408K$ (single layers)

Update on cost estimates Strip planes (includes glueing the ribs aside the LSTs) Total cost of Z /PHI readout strip plane [Euro]:90318 of which labor is (80%) [Euro]: 72255

Update on cost estimates PCBs for strip signal collection Total cost of Z strip PCBs [Euro]: 13320of which labor is [Euro]: 9990 Total cost of PHI strip PCBs [Euro]: 4425of which labor is [Euro]:

Update on cost estimates HV cables including soldering of terminations Total cost of KERPEN HV cable [Euro]: 2695 Total cost of GND return LV cable [Euro]: 7473 Total cost of terminating KERPEN HV cable [Euro]: of which labor is [Euro]: Total cost of terminating LV cable [Euro]: of which labor is [Euro]: 8304

Update on cost estimates Signal cables including crimping of headers Total cost of microribbon flat cables [Euro]: Total cost of microribbon connectors [Euro]: add labor for crimping [Euro]: 6288

Update on cost estimates Electronics Total cost of electronics [Euro]:

. TDC system: 20 K$ HV system 11 SY546 systems with 87 A ch Active boards SY546 Main: 3300 $ A CH Active: 1400 $ Tot: 3300 x x 87= $ 11 Distribution boxes = $ Total HV system : 168 K$ Update on cost estimates

Total cost gas system 50 K$ DAQ, cooling no expected cost Grand total detector 955 K$  1090 K$