# Presentation: 182790

## Silicon Strip Detector

- Extended status report
- Lilian Martin
- March 27th, 2006

## Detailed Items

- Hardware
- Hardware on the cone
- Hardware on the TPC wheels
- Hardware on the pole tips
- Hardware in the WAH and AB
- Hardware on the south platform
- Hardware in the DAQ room
- Hardware in the control room
- Documentation on the hardware
- Documentation on operating the SSD
- Documentation (general)

- Software and data analysis
- Online software
- StSsdDaqMaker : raw data converter
- StSsdPointMaker : hit finder
- StSvtEvalMaker : SSD global alignment
- Pedestal and noise calibration
- Gain calibration
- Simulation chain
- List of contacts

## Hardware on the cone

- Items :
**20 SSD ladders** are installed on the cone. They are attached to 4 separated sectors (2 big and 2 small sectors) . The SSD has been progressively installed (1, 10 and finally 20 ladders).
- An **electrical shield** (aluminized Mylar) separates the SSD from the IFC.
- Expertise :
- The SSD was designed and built by both the IReS and SUBATECH groups.
- The SSD structure, electronics and mechanics are described on the web.
- G.Guilloux, S.Bouvier and L.Martin are experts in mechanics
- S.Bouvier and L-M.Rigalleau are experts in the control and ADC electronic boards
- L.Martin has some knowledge on the task related to the shield installation.
- Maintenance :
- Failing ladders have been replaced several times. HV decoupling capacitances have been replaced on all ladders. For this task, the SSD has been completely removed from the cone. Maintenance on the SSD ladders has been routinely done. Dedicated tooling exist to remove and install the SSD sector on the cone.
- Failing ladders have been usually replaced and shipped back to France for repair. Two spare ladders are always available to replace ladders featuring new failure (usually on the electronic boards).

## Hardware on the TPC wheels

- Items :
**4 readout boards** read and communicate with 10 half ladders each. Two are installed on each side of the TPC and on the top of 2 SVT readout boxes (at 6 and 7 o’clock). The boards are installed in a box mechanically attached to the SVT rdo boxes. The backside of the box features a quick connector to plug an air hose for the cooling of the board.
- The rdo board is a key element since a software is uploaded in its FPGA and in the FPGAs on the adc and control boards on the ladders.
- Expertise
- The boards were designed by the electronics team at Subatech. Christophe Renard designed the board.
- Documentations : Christophe Renard has posted all the information related to his board on the web at this URL :
- Experts : Christophe Renard (Subatech) and Stephane Bouvier (Subatech)
- Maintenances
- The board has never needed any hardware maintenance during the last few years.
- The weak connection between the optical transceiver and its socket on the board has been mechanically secured.
- Several generations of rdo boards exist with minor modifications which can easily used as spares.
- The main maintenance operations were software upgrades.

## Hardware on the TPC wheels

- Items :
**20 flexible air hoses** (tygon) emerged from the cone ends (10 on each side). They go through the air partition apertures and are connected to the air manifold.
**4 air manifolds** connect the air hoses to the 4 vortec and act as a fan in-fan out for the induced air flow. They fit inside partly opened tubes attached to the SVT water hose shoe located at 4 and 8 o’clock.
- Expertise
- These elements were designed or selected by Subatech.
- A document posted on the web gives some indication on how to route the hoses.
- Experts : S.Bouvier, G.Guilloux and L.Martin (Subatech), B.Soja (BNL)
- Maintenances
- The air manifolds do not need any particular maintenance.
- The air hoses are quite soft and were collapsing when subject to small bending radius. Their path has to be carefully checked to make sure enough air flow is going through them especially at the location were they emerged from the SVT air partition. One has to carefully inspect the connection of the hose dedicated to the rdo boards since it is located into a very confined space
- Some of these hoses have been recently encapsulated into more rigid hoses (blue) with an inner radius slightly bigger than the air hose radius. Some connectors were also added in the middle of some hoses to allow quite disconnections and prevent the hose to collapse at these particular locations.

## Hardware on the TPC wheels

- Items :
**20 LV+HV power cables**** **on each side are coming from the SSD rack on the south platform and are connected to the cables emerging from the cone. 10 cables on each side carry the HV while the others are only providing LV (-2V, +2V and +5V). When reaching the STAR magnet, the cables are separated and following different paths depending on the ladder they are serving. The connectors at the end of the cables are AMP connectors and feature both male and female pins. Once connected to their corresponding cables emerging from the cone, the connections are secured using cable tights.
- Expertise
- These elements were designed or/and selected by Subatech and IReS.
- Documentations posted on the web give some indication on how the cables are routed around the TPC wheels and their specifications.
- Experts : S.Bouvier, L-M.Rigallaud  (Subatech) and D.Bonnet, F.Littel (IReS)
- Maintenances
- Usually during the shutdowns, the cables are disconnected from the cone cables and they are removed from the TPC wheels up to the magnet radius. During that time the connector may be exposed. Few times several connectors had been broken, usually the body of the connector made of plastic. They are relatively cheap and can be easily replaced.
- About 15 spare cables of various length are stocked in the STAR stock building. The shortest is long enough to reach the farest ladder.

## Hardware on the TPC wheels

- Items :
**4 slow control cables, 2 trigger cables, 6 optical fibers and 2 power cables** are equally installed on both wheels. The trigger cables are coming from the trigger rack on the south platform. They are equipped at their end on the wheel with a flat cable extension featuring two connectors and properly terminated. All the other cables are coming from the SSD rack. 4 fibers (out of 6) are used. The others are available as spares and are only routed up to the south platform (where a patch panel provides lines already reaching the daq room). The two power cables are equipped at their end with a short Y-shape extension allowing to power the two rdo boards installed on each side.
- Expertise
- These elements were designed or selected by Subatech and IReS.
- Experts : S.Bouvier, L-M.Rigallaud  (Subatech) and D.Bonnet, F.Littel (IReS)
- Maintenances
- These cables had not needed any maintenance operations so far. Two additional optical fibers have been installed and are routed up to the south platform and stored under the first floor near the trigger rack.
- Spare fibers and round to square shape adapter can be found in the SSD cabinet.

## Hardware on the pole tips

- Items :
**4 transvectors** (vortec) are installed on the pole tips to produce an induced air flow into an hose connected to 5 individual ladders. The air flow resulted on the Venturi effect produced by 120 psi compressed air liberated in the vortec volume. The flow amplitude is determined by the thickness of a shim in the vortec. Before reaching the vortec, the compressed air goes trough a filter and a manual valve allowing to reach a stable pressure of 5 bar). They are  both very close to the vortec and share a common support on the pole tips.
- Expertise :
- The system was designed by Subatech and BNL. The system has been installed by the STAR Technical Operation group.
- Documents : the SSD cooling system document is available online. The various elements (filter, gauge,...) are described on the web.
- S.Bouvier and G.Guilloux (Subatech), R.Brown and B.Soja (BNL)
- Maintenance :
- The vortec have been maintained : cleaning and shim replacement. It cost is modest and covered by the STAR maintenance budget. This maintenance has been performed by B.Soja

## Hardware in the assembly building and the wide angle hall

- Items :
**A setup (compressor, filter, tank)** is installed in the second floor of the assembly building and provide clean and dry compressed air (120 psi).
**A line** links the compressor to the vortec mixing copper pipes and flexible hoses.
**A solenoid valve and a gauge** allows to monitor and control the compressed air flow. The are read by the SVT slow control system.
- Expertise :
- The system was designed by Subatech and BNL. The system has been installed by the STAR Technical Operation group.
- Documents : the SSD cooling system document is available online. The various elements used to build the compressed air line are described on the web.
- S.Bouvier and G.Guilloux (Subatech), R.Brown and B.Soja (BNL)
- Maintenance
- The compressor had failed several times over the passed few years. A major maintenance has been done under the supervision of the STAR Operation group.

## Hardware in a rack on the south platform

- Items :
**Two CAEN power supply crates** are installed in the SSD rack and are filled with LV and HV boards. Most of the slots are filled with used boards. Three different board models are used to provide HV (typically 50V) and LV (-2V, +2V and +5V).
- The boards and the crates are controlled by the SSD slow control system.
- Expertise
- The CAEN system was chosen by the IReS group
- The specs of the crate and boards are available on the SSD web pages.
- Experts : D.Bonnet and F.Littel (IReS)
- Maintenance
- The LV boards have been erratically failing during the last runs. During the last shutdown, all the boards have been inspected and very poor thermal connections between driver components and their supports have been identified as the cause of the failure. Bad contacts have been secured and most of the others have been visually inspected.
- The number of spare elements is rather small. Only one spare board per model and no spare crate. The models used are obsolete and very expensive.

## Hardware in a rack on the south platform

- Items :
**Two patch panels** are installed in the SSD rack. They are used to combine the various power lines (-2V, +2V, +5V, HV, senses) coming from the CAEN crates together to power individual (half-)ladder. One panel is dedicated to the N-side ladders (East side) while the other serves the P-side ladders (West side). Their are installed in between the two CAEN crates. All input on the patch panels are equipped with fuse boards.
**40 LV cables and two HV cables**. These short cables are connected to both the power crates and the panels. They are relatively short (1.5 m long) and partly dedicated to specific power lines. The –2V cables should not be used for an other power line. The HV cables are simple flat cables.
- Expertise
- The panel and cables were chosen by the IReS group and the SUBATECH group.
- The specifications of the cables and panels are available on the SSD web pages.
- Experts : D.Bonnet and F.Littel (IReS), S.Bouvier and L-M.Rigalleau (SUBATECH)
- Maintenance
- The cables and the patch panels never needed any particular maintenance operation.
- Few spare cables and fuse boards are stored in the SSD cabinet.

## Hardware in a rack on the south platform

- Items :
- A** slow control crate **installed in the SSD rack. The crate is a WEINER VME crate remotely controled via its canbus interface. The crate is filled with several boards :
- A **processor board** (VME-167) running VxWorks OS, an **interface board** (V288 –Caenet) to communicate with the CAEN crates and an **interface board** (Corelis CVME 1149) for the JTAG communications.
- A **distribution board** is the key element for the communications with the SSD readout boards.
- Expertise
- The slow control system was designed by the IReS group.
- Some documentation on the slow control hardware is available on the SSD web pages.
- Experts : D.Bonnet and F.Littel (IReS)
- Maintenance
- The slow control hardware has been working stably over the past runs.
- A spare of each board (except the crate) is available and stored in the SSD cabinets. A spare version of the distribution board is currently in France.

## Hardware in a rack on the south platform

- Items :
- A **relay box **is installed at the back of the VME crate in the SSD rack. This box contains various relays and a voltage transformer used for the SSD control itself and the STAR interlock implementation.
- A **power supply **(Lambda)** **dedicated to the SSD readout board power is installed at the same location. Between the power supply and the rdo board power cables a fuse box has been installed in order to limit the power consumption.
- Expertise
- The slow control system was designed by the IReS group.
- Some documentation on the slow control hardware is available on the SSD web pages.
- Experts : D.Bonnet and F.Littel (IReS).
- Maintenance
- The relay box and the power supply connections have been improved and secured over the past years. P.Kuczewski who did some of these repairs has some experience on these parts.
- A spare Lambda power supply and some spare parts of the relay box are stored in the SSD cabinet.

## Hardware in the acquisition room

- Items :
- A **DAQ crate **equipped with 4 receiver boards is installed in the STAR acquisition room and is dedicated to the SSD subsystem. Each board is dedicated to a SSD rdo board.
- On the left side of the crate, **6 optical fibers **are emerging from the DAQ room floor. Half of them is directly coming from the TPC wheels while the other half is first connected to the patch panel  located near the middle of the daq crate wall.
- Expertise
- The crate and its boards was provided by the DAQ group.
- The matching table between the SSD rdo board, SSD optical fiber and the DAQ receiver boards is posted online.
- Experts : the DAQ group.
- Maintenance
- The DAQ group is maintaining the crate and the boards.

## Hardware in the control room

- Items :
- A **SUN station **(ssdsun01.starp.bnl.gov) has been installed and is dedicated to the slow control and monitoring of the SSD. The **epics software** has been installed on this machine. The VME board is booting from this machine. The VME board software dedicated to the SSD monitoring is also loaded from this machine. A Web server and a channel archiver are also running on this machine.
- A **Linux box** (ssdlinux01.starp.bnl.gov) is installed near the sun station and was originally dedicated to online monitoring of the SSD data. For that purpose, the daq disk are mounted and specific software has been maintained for online analysis or offline analysis of collected data. Recently the slow control software has been duplicated from the sun station on this machine. The slow control monitoring can thus be done from it now.
- Login conditions on these machines are explained in the SSD operation guide and/or can be obtained from the experts.
- Expertise
- The machines were brought from France and installed by the two French groups.
- Experts : D.Bonnet, L.Martin, J.Baudot
- Maintenance
- These computers are out of date but are running well since few years. Some software from the ITD has been installed on ssdsun01 to backup specific directories.W.Betts had some knowledge of these machines.

## Documentation on the hardware

- Most of the hardware information is available online on the SSD web site :
**The « Documents » page** contains links to various useful document :
- The SSD technical proposal and the SSD section of the STAR NIM paper
- The status reports presented during the collaboration meetings
- The talks/seminars given on the SSD while the SSD was under construction.
- A collection of images and pictures (the « photothèque » section)
**The « Hardware » page** contains more technical information :
- A specific document dedicated to each particular aspect (electronics, cooling,...) of the SSD
- The mechanical drawings
- Various documents (manual, reports, web pages ) on specific item.
- The documents describing the tasks performed during the shutdowns (past years section)

## Documentation on operating the SSD

- Most of the useful information to operate the SSD is also posted on the web :
- The** Operations page** contains essential information to operate the SSD :
- Various information important to the shift crew
- The updated SSD operation guide.
- A document on the SSD cooling system operation.
- A page showing typical online SSD QA histograms.
- A list of current problems
- Expert email addresses and phone numbers
- Some useful information for the experts and people allowed to play with the SSD hardware and software.
- The **Online page** contains heterogeneous information :
- Some old information on the slow control
- SSD geometry information
- A link to the page dedicated to the calibrations (pedestals, gain, alignment).
- The** DATA page** contains test results and first data taken after a shutdown :
- Pedestal and noise measurement
- Calibration results,...
- Matching tables between the ladder Id and the daq data.

## Documentation

- The SSD web site has been migrated from a web server at Lyon to the STAR web server at BNL.
- Most of the pages and documents have been transferred and should be available online.
- Few documents have been recently posted on the STAR Drupal tool accessible from the SSD page stored in the sub-system area. (http://online.star.bnl.gov/STAR/subsys/ssd/)

## Software and data analysis

**Online software**
- Some online software specific to the SSD is located on the ssdlinux01 machine. This software is useful to quickly look at online data (besides the Panitkin plots) or offline data freshly taken.
- The code is run from the /home/star/Online directory. It has been developed  from the template (special.c) provided by the DAQ group. Several histograms are produced (and saved in ps file) : pedestal and rms distributions, ladder occupancy, raw signal distributions... The code is self documented and is the same since several years.
- A large fraction of the histograms defined in this code has been recycled as specific to the SSD in the Panitkin plots.
- In order to analyze data, some daq disks are mounted (/evb01_x where x=a, b, c or d and /starevpa and /starevpb). If not, a simple mount command with the directory as an argument will mount the disk.

## Software and data analysis

**StSsdDaqMaker : raw data converter**
- Goal :
- The reconstruction of real data starts with the StSsdDaqMaker. This maker reads the raw daq data and converts them (with the help of a matrix) into a table containing a strip id and the signal value in adc count.It reads both physics data and pedestal/noise data and produces suited table
- Status :
- The code is stable and in cvs
- Know issues :
- For some ladders, an offset of one had to be introduced in the conversion matrix. Without it, the alignment plots do not show meaningful pattern. The exact reason for that offset is still not fully understood but the ad hoc correction works.
- Signals from noisy detectors/ladders are converted while they can easily be suppressed in that maker. An (existing) configuration can be used to ignore specific ladders or wafers.

## Software and data analysis

**StSsdPointMaker : SSD cluster and hit finder.**
- Goals :
- This maker reads the pedestal tables, convert them into a more suitable format and write them in a root file on disk with a filename containing the associated timestamp.
- This maker reads the real (zero-suppressed) physics tables, does the cluster finding, cluster matching, hit reconstruction and finally write them into a StEvent hit container.
- Several histograms are produced for QA
- Status :
- The code is stable and in cvs
- Know issues :
- In the cluster matching, the code does not decide yet which hit combination is the best. All possible combinations are written in StEvent. The association with the best (highest) probability must (and can easily) be selected.
- The relative gain calibration results must be integrated in the code. This is important for dE/dx capabilities and for the ambiguous hit de-convolution in a high local particle density (typically Au+Au at full energy)

## Software and data analysis

**StSvtEvalMaker : SSD global alignment.**
- Goals :
- This maker is used to improve the global SSD alignment using track to hit association. It reads StEvents containing TPC (+SVT) tracks and SSD hits, loads a given geometry and does track to hit associations based on relative distances.
- Track and hit information are stored in an ntuple which is used to identify correlations signing possible misalignment.
- Status :
- The code is stable and in a private directory (/afs/rhic/star/users/lmartin/Aligment2). Some documentation exist in the directory (README.txt).
- Results for the Cu+Cu at 62 GeV have been posted here :
- http://www.star.bnl.gov/~lmartin/Alignment/CuCu62FF/AlignmentCuCu62FF.html
- Known issues :
- The code would need some cleaning for a commit.

## Software and data analysis

**SSD pedestal and noise calibration.**
- Goals :
- Pedestal runs are usually taken at the beginning of each store during the data taking period ie typically few times per day. The pedestal and noise values of each strip are used in the cluster finder procedure of the StSsdPointMaker. They are loaded in the InitRun of the maker from the db. The StSsdPointMaker itself is used to produce a root file containing the ped/rms values before insertion in the db.
- .
- Status :
- A complete analysis of the Run V pedestal runs has been done and results have been posted here : _[http://www.star.](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[bnl](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[.](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[gov](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[/~](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[lmartin](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[/Calibration/](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[PedAndRms](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)__[.html](http://www.star.bnl.gov/~lmartin/Calibration/PedAndRms.html)_
- This calibration was performed from the directory : /afs/rhic/star/users/lmartin/Calibration and the output files were stored in : /star/data06/SSD/pedestal_calibration/run5/AfterDaq
- Known issues :
- The very large amount of data to store in the db must be reduced. Typically, only pedestal and/or rms values that have changed by x% with respect to their previous values must be inserted in the db. Temporarily fix can be done by using a unique cut in the StSsdPointMaker (a default value in the StSsdStip object constructor).
- Existing root files are may be in an obsolete format. They should be easily reproduced using the xml files located in the dedicated directory.

## Software and data analysis

**SSD gain calibration.**
- Goals :
- Correction of the gain difference on a chip basis. Jerome Baudot had done an extensive study of the gain response of the SSD using pulser runs. It is assumed that the gain is uniform within a given FEE chip. The observed differences are of the order of few percents. This gain calibration is useful to refine the cluster charge matching results and the SSD capabilities in terms of dE/dx.
- Status :
- Jerome has posted his results here : _[http://www.star.](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[bnl](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[.](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[gov](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[/~](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[baudot](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[/](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[ssdWork](http://www.star.bnl.gov/~baudot/ssdWork_index.html)__[_index.html](http://www.star.bnl.gov/~baudot/ssdWork_index.html)_ and in the daughter pages (pulser runs and calibration).
- Known issues :
- The gain corrections are not implemented in the StSsdPointMaker. A dedicated table must be defined to store the values in the db and to be loaded by this maker to correct each adc signal on a strip basis. Pedestal and rms values must be corrected accordingly.
- Some FEE chip pulsers are not working. They thus need an other type of gain calibration. This can be easily achieved using real data and by selecting non ambiguous hits made of one strip clusters and by fitting the resulting charge P vs charge N correlations.

## Software and data analysis

**Simulation chain.**
- Goals :
- The geant description of the SSD has been recently updated.
- The simulation chain is at the moment split in three parts :
- The StSsdSimulationMaker that takes hits from gstar simulated event, generates signals on strips and mimick the daq behavior (zero suppression, compression)
- The StSsdClusterMaker that takes the simulated daq data and does the cluster finding and hit reconstruction.
- The StSsdEvalMaker that takes the various tables produced by the simulation makers and evaluation the performances.
- Status :
- The code is in cvs and has been recently cleaned by A.Kisiel.
- Known issues :
- The StSsdClusterMaker and the StSsdPointMaker are doing the same tasks on simulated and real data. They should be merged in order to be able to do embedding.
- The simulation maker assumes some homogeneous defects in the SSD. The best would be to simulated data using real data figures (pedestal and rms values for instance). Thus the code should be modified to read/load pedestal table.

## Contacts

- People involved during the construction, installation and first years of operations who are good sources of information :
- At Subatech (email = firstname.lastname@subatech.in2p3.fr):
- S.Bouvier : engineer in electronics, broad knowledge on all aspects of the SSD, specific expertise on the electronics
- C.Renard : engineer in electronics, designer of the rdo board.
- L-M.Rigalleau : technician in electronics, designed the ADC board.
- Gerard Guilloux : engineer in mechanics, designed almost each mechanical piece.
- L.Martin : physicist, broad knowledge on all aspects of the SSD.
- At IReS (firstname.lastname@ires.in2p3.fr)
- D.Bonnet : engineer in electronics, specific expertise on the module electronics, designer of the slow control system.
- F.Littel : technician in electronics, specific expertise in the cabling and the slow control hardware.
- J.Baudot : physicist, broad knowledge on all aspects of the SSD.