Muon Telescope Detector (MTD)

The MTD is a large-area and cost-effective detector at mid-rapidity for the STAR experiment at RHIC. It utilizes the new Time-Of-Flight system with precise timing, and provides excellent muon trigger as well as identification capabilities in the high-luminosity era at RHIC.

Data production


Offline software


Plots & pictures





MTD Calibration

Calibration Parameters

  • Trigger Time Windows -- limit the MTD hits to those that are within a certain window w.r.t. the central TOF clock
  • INL -- apply the Integral Non-Linearity electronics calibration (specific to the HPTDC chips) 
  • T0 -- align the timing of all the MTD channels
  • Slewing -- calibration for amplitude (time-over-threshold) depended timing effects
  • Alignment -- correct MTD/TPC alignment, using the residuals between matched TPC track and MTD hit pairs


A schematic workflow is shown here, and a detailed description can be found in Calibration Workflow. Details about the calibration procedure can be found here

Parameter Storage

  • The calibration parameters are stored in the data base
  • These parameters can also be found here

Calibration Parameters

Run19 (BES II)

Run18 (200 GeV Isobar, 27 GeV Au+Au)

Run17 (500 GeV p+p, 54 GeV Au+Au)

Run16 (200 GeV Au+Au, 20-200 GeV d+Au)

Run15 (200 GeV p+p, p+Au)

Run14 (200 GeV Au+Au)

  • Determine timing window for cosmic ray data: slides
  • Determine timing window for real data: slides
  • Compare mean and sigma of dT distributions between data and cosmic ray: mean, sigma

Run13 (510 GeV p+p)

  • Determine timing window for cosmic ray: slides
  • Determine timing window for real data: 130-149, 151-161
  • Check timing window vs. day: slides
  • Compare mean and sigma of dT distributions between data and cosmic ray: mean, sigma


 Database Tables and Handling


  • Database tables are used in every StEvent-based Maker with run-depend information ranging from electronics maps, timing windows, to calibration information, and detector status.
  • Web access to offline database browser: STAR Database Browsers

MTD database summary

  • Geometry/MTD
    • mtdTrayToTdigMapmap from the Tdigit number stored in raw data to the tray number which ranges 1-5
    • mtdTrayIdMap: map to the tray Id number in the UT database. This is the only valid way to find out which Tdigit broad has been mounted onto the tray in case some trays are moved around onsite.
    • mtdTdigIdMap: map to the Tdigit board Id from the UT tray Id. This is needed for the INL correction.
    • mtdGeant2BacklegIDMap: map to convert from the backleg ID in GEANT to that in real data.
    • mtdModuleToQTmap: mapping between MTD backleg/module to the triggering QT board.
  • Calibrations/MTD
    • mtdTriggerTimeCut: cut on the timing difference between MTD hits and trigger time recorded by THUB to reject the MTD hits that are not from the triggered collisions, i.e. pileup
    • mtdT0Offset: T0 offset for MTD calibration
    • mtdSlewingCorr: slewing correction for MTD calibration
  • Calibrations/tof
    • tofINLSCorr: the INL corrections for MTD modules resides together with the TOF parameters
For detailed defintions of MTD tables in the database, please refer to: MTD tables.

MTD operation

This page collection information regarding to the MTD operation.

MTD+TOF operation manual for detector operator and on-call experts

MTD dimuon trigger commissioning
MTD trigger map

MTD trigger algorithm
The algorithm documents can be found in
  • For QT algorithm: the link name is "Algorithm 6c - MTD (MT001->4) "
  • For DSM and TCU algorithm: the link name is "TOF Branch: TOF, MTD and PP2PP Algorithms for Beam Running"

MTD reference plots for shift crew

Offline Software

Offline Software Organization & Development


Schematic overview

An overveiw of the offline software strucuture for MTD is shown. The detailed documentation can be found here: MTD software document



Macro: for running all the standard MTD makers on StEvent or MuDst input, see MTD macro.
Access MTD information: for examples to access the MTD hit information and pid information, please refer to the function processStEvent() and processMuDst() in StMtdQAMaker.

BFC options/workflow

For explicit definitions, see CVS log for StRoot/StBFChain/BigFullChain.h

  • mtd -- loads all MTD chain Makers: StMtdHitMaker, StMtdMatchMaker, and StMtdCalibMaker.
    • note: it may also need to include StBTofHitMaker and StVpdCalibMaker for VPD start time information
  • mtdSim -- Simulation chain: Loads StEvent and StMtdSimMaker
  • mtdDat -- Raw data chain only: loads StMtdHitMaker
  • mtdUtil -- loads StMtdUtil (usually automaticall included, no need to explicitly call)

Useful links

STAR CVS repository:STAR CVS

STAR Doxygen pages: StRoot (doxygen)

MTD Offline Software Projects

MTD Offline Software Projects: Description & Status of MTD Software Projects

This page lists the various ongoing MTD offline development projects, with contact information and current status


  • raw data decoding, basic mapping, persistent storage in StEvent and MuDST. [done]
  • StMtdRawHit implementation, and offline INL application. [done]
  • include electronics mapping
  • INL calibration
  • StMtdHit creation (incl. MuDST)
  • people: Xinjie Huang, Xianglei Zhu, Frank


  • hit selection & sorting
  • track extrapolation
  • hit-track matching algorithm development & implementation
  • people: Chi Yang, Wangmei Zha, Bingchu Huang, Frank


  • database table design
  • algorithm development & implementation
  • StMtdPidTrait creation
  • people: Frank + TBD


  • implementation of the framework, read GEANT data and convert to basic hits. [done]
  • Fast & Slow simulation algorithm implementation
  • apply electronics mapping
  • data comparison
  • people: Shuai Yang, Ming Shao, Frank



MTD operation

Detector operation

For MTD operation, please see STAR operation

Trigger documents





More trigger related documents can be found on trigger page.

MTD HV CAEN Board (A1534) Settings.

 When installing a new board into a SY4527 mainframe, the settings on the board are configured to the previous use-so factory settings or test bench settings.  To check/configure the board, there are (at least) two ways to go about it [ CAEN HV Control Software or EPICS].

The boards used in mtd-hv are A1534s.

Easiest(?) Method:
Use CAENHVControlSoftware. so on mtd@mtd-cr, cd to /home/mtd/CAENHVControlSoftware-1.1.2/bin/
then: ./CAENControlSoftware

[This software is outdated, but does the job.]

A GUI should pop up, on the top left menu- click File->Connect.

log in to mtd-hv as admin.

and then a couple more guis should pop up inside the main GUI and look something like this: .

Then click on the parameters you want to adjust and type in the new value and carriage return.

[02/02/2016 a new board was installed into slot 5]

In this case, Board05_Chan00*.

 So here I changed:
 V0Set to 6400 for full voltage (was 0, could have set to standby if wanted instead)
 I0Set to 100uA to match the other boards(was 20uA)
 RUp to 8Vps (was 50Vps)
 RDWn to 30Vps (was 50Vps)

Everything else was the same on the board(except for V1Set & I1Set, but we do not use those--we could for standby&change the control operations a bit...).

Second Method:
Use EPICS. The commands to monitor and set the parameters through epics can be sent almost anywhere on starp that has epics running, but use mtd-cr just to be safe.

To monitor:
caget MTD:HV:Negative:5:0:v0set

v0set = the demand voltage setting
i0set = the max current setting
rampup = ramp up rate
rampdn = ramp down rate

To set:
caput MTD:HV:Negative:5:0:v0set 6400

To check to see which variables are available to read/set, you can look at (on mtd-cr) /home/mtd/MTD/HV/HVCAENx527_3.7.2/db/MTDHV.db . Use less to look at the file, we do not want to modify it!

Random tidbits:
New board installed: A1534 (neg.) ser. no. 71 board fw: 04.
Current boards(A1534s) slot(1,3,5,7);  ser no (59, 69, 71, 61); fw(3.01,3.01,04.,03.); charge(-,+,-,+)  ramp up rate: 8v.s, down: 30v/s, max current 100uA.  max V 8k.


MTD HV SY4527 Firmware Upgrade

An entry describing the steps needed to update the firmware for the MTD HV Crate(mtd-hv.starp & model: SY4527)
(install by Joey & Shuai)

MTD crate firmware: 1.0.0
FPGA firmware: 0.04 build c723

This is indicated from the tech. info. page through the CAEN HV Control Software, as indicated here:

To update the crate, the firmware(1.3.1) was downloaded from the caen website, .
The package,, was unzipped on a local directory at mtd@mtd-cr.starp
And the firmware, sy4527-5527-HVFw-1.3.1-b20150608.bin, was used to upload to the crate.

To upload the firmware to the crate, there are two possible methods(at least).  Uploading via webserver or usb stick.  Uploading via webserver was used for this upgrade.
This was done by going to the Upgrade Firmware menu.  This should be accessible through the crate's web configurator.  In this instance, the CAEN HV Control Software was used to access the web configurator.
To get there, click on the "Settings" button located on the left menu in the image listed below:

Once clicked there, go to the "Upgrade Menu" on the top and select "Firmware Upgrade"
Here, select to upload the firmware bin file.
Once done, you should see the message: "Update Done!" in a green box as indicated in the image below:

Turn off the crate.
Wait 30 seconds.

At this point, make sure everything trying to talk to crate is turned off.   Eg: CAEN HV Control Software, HV IOCs, etc.  [Do not worry about the ethernet cable itself]
We do not want to mess with the crate while it is installing the new firmware.  (no inadvertent power reset, etc.)

Turn on the crate.
Wait 10 minutes for the installation to be complete.  [Do not touch/access until 10mintues have passed.]

Check that the installation is complete.
One can check the tech. info. page(or the web configurator's sidebar) and see that it was successful:

Note: the firmware version is mis-reported via this version of the CAEN HV Control Software, but it correctly reported through the web configurator.

The crate firmware has now been updated with the FPGA firmware.
firmware: 1.3.1
FPGA firmware: 0.06 build d910

PicoDst production

The page collects information about the PicoDst productions. The MTD information is integrated into the Berkeley PicoDst structure developed by Xin. Here are some useful links about the structure and details of the PicoDst:
Xin's webpage
CVS repository
Documentation of PicoDst structure

MTD PicoDst production list 

Data set Trigger Vertex selection & Event cuts  Track cuts Event/Track filter PicoDst production code & Storage   





Run 2013
pp @ 500 GeV

Di-muon: 430103, 430113
Single-muon: 430101, 430111
e-mu: 430102, 430112, 430122 
Vertex selection: select the primary vertex that has at least two associated primary tracks matched to MTD hits, otherwise the default primary vertex is used.

  • ! (Vx==0 && Vy==0 && Vz==0)
  • |Vz| < 2000 cm
  • |Vr| < 10 cm
  • RefMult >= 0   



  • Global tracks
  • 0 <= flag <= 1000
  • pT > 0.1 GeV/c
  • nHitsFit >= 15
  • nHitsFit/nHitsPoss > 0.52
  • gDCA < 10 cm 

Library: SL15e_embed

Code in CVS






Run 2014
AuAu @ 200 GeV


Di-muon: 450601, 450611,
450621, 450631, 450641
Dimuon-30-hft: 450604
Dimuon-5-hft: 450605, 450606
e-mu: 450602, 450612,
450622, 450632, 450642
Single-muon: 450600, 450610,
450620, 450630, 450640



Vertex selection: select the primary vertex that is within 3cm of VPD,
otherwise the default primary vertex is used. 


  • ! (Vx==0 && Vy==0 && Vz==0)
  • |Vz| < 1e4cm
  • |Vr| < 1e4 cm
  • RefMult >= 0   
  • Global tracks
  • 0 <= flag <= 1000
  • pT > 0.1 GeV/c
  • nHitsFit >= 15
  • gDCA < 10 cm  


Save only electron and muon candidates.

Electron PID: |nσe|<3.0 
EMC match && pT>1.5 GeV/c

Muon PID: match to MTD


Library: SL15e_embed

Code in CVS






 Run 2015
 @ 200 GeV 


Dimuon: 470602, 480602, 490602
e-mu:  470601, 480601, 490601
single-muon: 470600, 480600, 490600


Vertex selection: default vertex

  • ! (Vx==0 && Vy==0 && Vz==0)
  • |Vz| < 1e4cm
  • |Vr| < 1e4 cm
  • RefMult >= 0   



  • Global tracks
  • 0 <= flag <= 1000
  • pT > 0.1 GeV/c
  • nHitsFit >= 15
  • gDCA < 10 cm 



Save only muon candidates

Muon PID: match to MTD 


Library: SL16c

Code on RCF: /star/u/marr/mtd/PicoDst/Run15/StRoot/StPicoDstMaker/

Storage: /star/u/marr/data02/PicoDst/Run15_pp200/PicoProd


 Run 2015 pAu @ 200 GeV

Dimuon: 500602
e-mu: 500601
single-muon: 500600 


 Vertex selection: closest to VPD vertex



  • ! (Vx==0 && Vy==0 && Vz==0)
  • |Vz| < 1e4cm
  • |Vr| < 1e4 cm
  • RefMult >= 0   
  • Global tracks
  • 0 <= flag <= 1000
  • pT > 0.1 GeV/c
  • nHitsFit >= 15
  • gDCA < 10 cm 


Save only muon candidates

Muon PID: match to MTD  

 Library: SL16c

Code on RCF: /star/u/marr/mtd/PicoDst/Run15_pAu200/StRoot/StPicoDstMaker/

Storage: /star/u/marr/data02/PicoDst/Run15_pAu200/PicoProd


Plots & pictures

 MTD plots, pictures and photos

Plots can be downloaded in the attachment or the corresponding link.

Physics plots

Performance plots

Physics projection



Sketch of a cosmic ray traversing MTD

Mechanical pictures



Installation photos

Production afterburner

 The MTD afterburner mode allows new or alternative calibration parameters to be applied on MuDst files. Usually, the MTD hits and PidTratis are modified to relfect a better understanding of the MTD performance. These makers should be run before users' analysis makers.


Run13, pp 500, second part (day 130-161)

The following makers need to be run to select and calibrate MTD information:

// libriaries

// setting up chain and MuDST/DB Makers
StChain *chain = new StChain("StChain");
StMuDstMaker *muDstMaker = new StMuDstMaker(0,0,"",fileList,"MuDst.root",nfiles);
St_db_Maker *dbMk = new St_db_Maker("db","MySQL:StarDb","$STAR/StarDb","StarDb");

// initiate MTD hit maker to apply trigger time window cut used to reject background hits
  StMtdHitMaker *mtdHitMaker = new StMtdHitMaker("mtdHitMaker");

// match maker needs to be re-run everytime hit maker is re-run
  StMagFMaker *magfMk = new StMagFMaker; 
  StMtdMatchMaker *mtdMatchMaker = new StMtdMatchMaker();

// Use calibration maker to apply the calibration parameters
  StMtdCalibMaker *mtdCalibMaker = new StMtdCalibMaker("mtdcalib"); 


MTD publications


Measurements of inclusive J/psi suppression in Au+Au collisions at \sqrt{sNN} = 200 GeV through the dimuon channel at STAR Link
Measurements of the transverse-momentum-dependent cross sections of J/psi production at mid-rapidity in proton+proton collisions at \sqrt{s} = 510 and 500 GeV with the STAR detector Link


Muon identification with Muon Telescope Detector at the STAR experiment NIM


Calibration and performance of the STAR Muon Telescope Detector using cosmic rays NIM 


Multigap RPCs in the STAR experiment at RHIC NIM


Performance of a new LMRPC prototype for the STAR MTD system NIM 


Perspectives of a mid-rapidity dimuon program at the RHIC: a novel and compact muon telescope detector proposal arXiv JPG


New Prototype Multi-gap Resistive Plate Chambers with Long Strips arXivNIM


Quality assurance

 This page collects the QA plots for data production


  • 20180615: Run17_pp510_picoDst
  • Issue 1
    • I ran my QA code on the picoDst files, and found an issue with the production. Only about 30% of the events survived the standard vertex selection cuts, i.e. |vz_TPC| < 100 cm and |vz_TPC - vz_VPD| < 6 cm. I think the reason for such a low vertex cut efficiency is that the default vertex is selected for picoDst files as the option "PicoVtxDefault" was used. However, given that these events were triggered with the VPD coincidence condition, it is better to use the option similar to that used for the standalone picoDst production, namely "PicoVtxMode:PicoVtxVpdOrDefault TpcVpdVzDiffCut:6", which selects the vertex closest to the VPD vertex. Therefore, a reproduction of the picoDst files will be needed by using the chain option mentioned above.
    • Jerome: At this stage, I suggest (request) we finish what we have ongoing and do not start new production wave of picoDSTs. The incoming format change (being discussed in a few forum) makes moving forward
      for all scheduled samples not optimal.
    • Reference: