# Presentation: 557560

## The FVTX detector in PHENIX

- Hubert van Hecke,
- Los Alamos National Laboratory
- for the  PHENIX collaboration

- Vtx (Mannel)
- Fvtx (HvH)
- RPC (Wei)
- TOF (Belmont)
- RPC gas (Wood)
- RPC (Kim)
- RPC (Meredith)
- Computing (Love)

- Forward Silicon Vertex Detector,
- one of a number of detector upgrades

## FVTX team

- R. K. Choudhury,  P. Shukla,  D. Dutta, A. K. Mohanty, Bhabha Atomic Research Centre, India; R. Pak, K.A. Drees, Brookhaven National Laboratory; H. Pereira, Saclay, France; M. Finger, M. Finger, Charles University, Prague, Czech Republic; J. Klaus, Czech Technical University, Prague, Czech Republic; P. Mikes, J. Popule, L. Tomasek, M. Tomasek, V. Vrba; Institute of Physics, Academy of Sciences, Prague, Czech Republic; B. Cole, E. Mannel, D. Winter, W. Zajc, Columbia University; J.C. Hill, J.G. Lajoie, C.A. Ogilvie, A. Lebedev, H. Pei, G. Skank,A. Semenov, G. Sleege, F. Wei, Iowa State University; Naohito Saito, KEK, Japan; T. Murakami, K. Tanida, Kyoto University, Japan; J.G. Boissevain, M.L. Brooks, S. Butsyk, G. Grim, H.W. van Hecke, J. Kapustinsky, A. Klein, G.J. Kunde, D.M.  Lee, M.J. Leitch, H. Liu, M.X. Liu, P.L. McGaughey, A.K. Purwar, W.E. Sondheim, Los Alamos National Laboratory; Hisham Albataineh, G. Kyle, V. Papavassiliou, S. Pate, X.R. Wang, New Mexico State University;** **T. Alho, M. Bondila, R. Diaz, D. J. Kim, J. Rak, University of Jyvaskyla, Finland;** **B. Bassalleck, D.E. Fields, M. Hoeferkamp, M. Malik, K. Spendier, J. Berndt, University of New Mexico, Albuquerque;  J.H. Kang, Y. Kweon, Yonsei University, Korea

## Goals of the FVTX

- Use heavy quarks (c,b) to study
-   properties of the QGP
-   q, g contributions to p spin
-   Drell-Yan
- Signal channel:
-   b->B->
-   c->D-> 
-   J/, ’-> 

- +

- -

- B,D have finite lifetimes, so they can be identified with a vertex tracker

## Separate signal from backgrounds

- Solution:
- D, B mesons travel ~1mm (with boost) before semileptonic decay to muons
- Mean ,K decay distance is much larger
- By measuring the DCA to the primary vertex, we can separate D, B decays from prompt muons and from long-lived decays from , K

- The problem: backgrounds (-> and K-> ) overwhelm the signal

## Detector Specifications

-  Need sufficient DCA resolution  (~100um)
-  Need occupancy low enough to find tracks in central AuAu events (<few %)
-  Need enough hits to reconstruct a track (>=3 hits)
-  Need to match tracks with Muon System:  = 1.2 - 2.4

## Model the detector 

- Geant-3-based simulations

- 3.750

- 12.5 cm
- 1664 strips
- 13 chips

- 2.8mm strip

- 11.2mm strip

- 75-um strips

## Other materials

- Materials that affect us:
-  - barrel silicon layers (4)
-  - support and cooling structures
-  - cabling and connectors
-  - beam pipe
-  - electronics board

## DCA resolutions

- Since the barrel pixels are // to the beampipe (orthogonal to the FVTX mini-strips, using them greatly improves phi resolution

## Occupancy

- Max track density in central Au+Au ~7/cm2

- Max. strip occupancy  ~ 2.8%

- -> choose 75 m strips

- /cm2

## Open charm, bottom signal

- Using DCA cuts, plus  and isolation cuts, we can now improve the signal/background for D,B->

## Improved resolution + background reduction

-  - better background   	  .  rejection
-  - better mass resolution
-  - separate ’

- Without FVTX

- With FVTX

## Mechanical design and prototypes

- Silicon sensor prototype from ON Semiconductor, CZ, under test at UNM

- Main unit: ‘wedge’

- Carbon backing
- Kapton HDI
- Silicon
- Readout chips

- Min To = 15oC

- Max To = 20.3oC

- Max deflection
- 10.4μm

- Heat flow studies

- Mechanical distortion studies

## Wedge -> Disk -> Cage assembly

- Mechanical design ~80% done

- Thermally conducting silicone

- Honeycomb support panel

- Wedges front and back

- Cooling inlet 15°C

- Cooling out 16.1°C

- Support cage

- 40 cm

## Readout chain

- FVTX readout chips
- ROC read-out card nearby
- FEM front-end module outside experimental hall

## 1) Readout chip (FPHX)

- Readout chip being designed at FNAL
- Derived from FPIX family of chips (BTeV), with (small) modifications
- ‘Pushes’ data to ROC - total bandwidth up to ~3.5 Tbps
- Low power: 100 W/channel, 50W total / 4 disks
- 2x13 chips per wedge, 128 channels / chip
- Total # channels: ~1.0M

## 2) ROC - readout card

-  One ROC combines data from 26 FPHX chips, send zero-supressed data to FEM over optical link
-  Download masks and thresholds to FPHX
-  Send clocks
-  Control calibration board
-  Implemented in rad-hard Actel FPGA

- prototype

## 3) FEM: front-end-module

-  FEM buffers data by beam crossing, 64 clocks deep
-  Deliver event upon LVL-1 trigger to Phenix DAQ
-  Send clocks down to IR
-  Implemented in Xilinx FPGA

## Test with prototype readout chip and ROC

- Calibration  using FPIX chips and readout cardprototype:
- Threshold / noise ~ 18:1

## Status and outlook

- Software:
-  - Simulations and analysis - in hand
- Hardware:
-   - Silicon detector prototypes undergoing tests
-   - FPHX chip being layed out
-   - HDI (Kapton interconnects) being layed out
-   - Readout electronics chain prototyped and running
-   - Mechanical design ~80% done
-   - Construction start in FY08
-   - Installation in Phenix in summer 2011

## backups

## External mount

## Acceptance

- Since the event vertex spans
- ~+-10 cm in z, we can use the barrel hits for some events.

- skip

## Can we match muon arm tracks with a FVTX track?

- 3 GeV muon:
- 75% correct match

- 9 GeV muons;
- 93% correct match

- Use the chi2 of the Kalman track fitter :

- skip