Cluster flags

TPC forum post 425:

I am sending a short description of the
TPX cluster finder flags. This is more an Offline issue
but I guess this is a better group since it is a bit
technical.

1) The flags are obtained in the same way other
variables such as timebin and pad are obtained.
I understand that this is not exported to StHit *shrug*.

See i.e. StRoot/RTS/src/RTS_EXAMPLE/rts_example.C

2) They are defined in:

StRoot/RTS/src/DAQ_TPX/tpxFCF.h

The ones pertaining to Offline are:

FCF_ONEPAD           This cluster only had 1 pad.
Generally, this cluster should be ignored unless
you are interested in the prompt hits where this
might be valid. The pad resolution is poor, naturally.

FCF_MERGED           This is a dedconvoluted cluster.
The position and charge have far larger errors
than normal clusters.

FCF_BIG_CHARGE    The charge was larger than 0x7FFF so
the charge precision is lost. The value is OK but the precision is
1024 ADC counts. Good for tracking, not good for dE/dx.

FCF_BROKEN_EDGE       This is the famous row8 cluster.
Flag will disappear from valid clusters
once I have the afterburner running.

FCF_DEAD_EDGE          Garbage and should be IGNORED!
This cluster touches either a bad pad or an end
of row or is somehow suspect. I need this flag for internal debugging
but the users should IGNORE those clusters!

        -- Tonko

TPC forum post 426:

I commited the "padrow 8" afterburner to the DAQ_TPX
CVS directory. If all runs well, you should see no more
peaks on padrow 8. The afteburner runs during the
DAQ_READER unpacking.

However, please pay attention to the cluster finder flags
which I mentioned in an email ago. Specifically:

"FCF_DEAD_EDGE          Garbage and should be IGNORED!
This cluster touches either a bad pad or an end
of row or is somehow suspect. I need this flag for internal debugging
but the users should IGNORE those clusters!"

         -- Tonko

Excess current seen in 2006

The attached powerpoint file from Blair has plots of the excess current seen in the IFC East for 2006.

Modeled distortions

Modeling the Distortion

This can be seen in the following plot, where I again show the distortion to laser tracks at a radius of 60cm (approximately the first TPC padrow) versus Z in the east TPC using distored run 7076029 minus undistorted run 7061100 as red data points. Overlayed are curves for the same measure from models of a half-resistor short (actually, 1.14 MOhm short as determined by the excess current of ~240+/-10nA [a full 2MOhm short equates to 420nA difference]) located at rings 9.5, 10.5, ..., 169.5, 179.5 (there are only 182 rings).

[note: earlier plots I have shown included laser data at Z = -55cm, but I've found that the laser tracks there weren't of sufficient quality to use; I've also tried to mask off places where lasers cross over each other]

The above plot points towards a short which is located somewhere among rings 165-180 (Z < -190cm). As the previous years' shorted rings were rings 169 and 170 ( = short at ring 169.5), it seems highly likely that the present short is in the same place. More detail can be seen by looking at the actual laser hits. The first listed attached file shows the laser hits as a function of radius for lasers at several locations in Z. The dark blue line is a simple second order polynomial fit I used to obtain the magnitude of the distortion at radius 60cm, which I used in the above plot. The magenta line is the model of the half-resistor short at ring 169.5, and the light blue line is the same for ring 179.5 (the bottom two curves on the above plot). Either curve seems to match the radial dependence fairly well.

Further refinement can be achieved by modeling the exact resistor chain. We have a permanent short at ring 169.5 (rings 169 and 170 have been tied together), and have replaced the two 2MOhm resistors between 168-169 and 170-171 with two 3MOhm resistors (see the attached photo of the repair, with arrows pointing to candidate locations for shorts via drops of silver epoxy). So it is more likely that we have a 1.14MOhm short on one of these two 3 MOhm resistors. The three curves in this next plot are:

• red: 1.14MOhm short on a 3MOhm resistor at 168.5, full short at 169.5, 3MOhm resistor at 170.5
• green: 1.14MOhm short on a 2MOhm resistor at 169.5, normal 2.0MOhm resistors at 168.5 and 170.5
• blue: 3MOhm resistor at 168.5, full short at 169.5, 1.14MOhm short on a3MOhm resistor at 170.5

We can also take a look at the data with the resistor in. Here is the same plot as before with a 1.14MOhm short at the same locations, but with an additional compensating resistor of 1.0MOhm. The fact that all the data points are below zero points again towards a short near the very end of the resistor chain, preferring a location of perhaps 177.5 over shorts near ring 170. These plots do not include the use of the 3MOhm resistors, but that difference is below the resolution presented here.

Zoom in with finer granularity between rings (every other ring short shown):

The second listed attached file shows the laser hits as a function of radius for lasers at several locations in Z for the case of the resistor in, again with magenta and blue curves for the model with shorts at ring 169.5 and 179.5 respectively.

Applying the Correction

170.5	171.5	175.5

Gene Van Buren
gene@bnl.gov

Choosing an external resistance for an IFC short

It is clear that when a field cage short is close to the endcap, it is best to add an external resistance to compensate for the amount of the missing resistance from the short as that would restore the current along the length of the resistor chain and only disrupt the potential at the last (outermost) rings instead of along the full length. A short near the central membrane would benefit less from this as restoring the proper current does restore the potential drop between each ring, but leaves almost all rings at a potential offset from the intended potential, essentially tilting the E field over nearly the whole volume.

But the question then comes as to whether we can decide on the best external resistance for minimizing the distortion, to align with the principle that the best distortion we can choose is the one which requires the least correction, in case we're not quite correcting it accurately. To answer that, the distortion modeling was run with a variety of locations for an IFC west 2 MOhm single-resistor short, and a variety of external resistances. The code to run this modeling has been attached as a tar file to this Drupal page in case there is interest to re-run it (e.g. for an OFC short).

Here are the results:

• Left: Surface plot showing the mean r-φ distortion we would get at the first iTPC pad row (radius = 55 cm) averaged over all active west-side z as a function of where the short is located ("ring of short") and how much external resistance is added.
• Right: Same but drawn as contours. The curve of interest to follow, that leads to <distortion>=0, is the one that starts near (ring,external resistance) = (110,0.0) and ends near (180,2.0), as indicated by the red markers. If the short is at ring 160.5, for example, then this curve indicates an external resistance of ~1.05 MΩ minimizes the distortions averaged over all active west-side z.

However, it may be more important to restrict the z range included in the distortion average, as most tracks of interest do not cross the inner pad rows at high z...

• Left: Similar surface plot, but restricting the average to 0 < z < 100 cm.
• Right: The curve of interest to follow in this contour plot, that leads to <distortion>=0, is the one that starts near (100,0.0) and ends near (180,2.0), as indicated by the red markers. If the short is at ring 160.5, then this curve indicates that an external resistance of ~1.25 MΩ minimizes the distortions averaged over 0 < z <100 cm.

Some additional observations:

• The curve of interest should always end close to (180.5,2.0), as that approaches the condition where the external resistance is no different than an internal resistance at the very end of the chain.
• The above is a simplification of what area should be integrated, as tracks with η ≠ 0 cross a variety of z at various radii, complicating the impact on their reconstruction. A track-by-track analysis of impact would be more meaningful, but a lot more work! The modeling shown here can serve as a rough guide to the best external resistance to use, but should not be taken as definitive for all physics.
• It is interesting to note that the model implies that a negative external resistance would help minimize the <distortion> when the short is closer to the central membrane (ring 0). A way to think of this is like having a short at both ends, such that the potentials are too high near the central membrane, and then too low near the endcap, so that the E field tilts one way in the region near the central membrane, isn't tilted at half the drift length, and then tilts the other way near the endcap, resulting in opposing distortions for electrons which drift the full length that serve to cancel each other. This could in principle be achieved by reducing the overall resistance of the Resistor box at the end of the Field Cage chain. The STAR TPC has (as of this documentation) had no persistent shorts near the central membrane that would warrant this approach.

-Gene

Other FC short distortion measurements

I considered the possibility that other measurements might help isolate the location of the short in the TPC. So, using the Modeled distortions, I modeled the effects of adding even more compensating resistance to the end of the IFC east resistor chain. Below are the results for shorts located at ring 165.5 (between rings 165 and 166), 167.5, 169.5, ..., 179.5 as indicated for the colored curves. All plots use a 1.0cm range on the vertical scale so that they can be easily compared. I had hoped that one resistance choice or another would cause more separation between the curves, giving better resolving power between different short locations. But this dependence is small, and actually seems to decrease a little with increased compensating resistance. Remember also that the last laser is at Z of about -173cm.

Also perhaps worth noting is that the 1.0MOhm compensating resistor probably helps reduce the distortions even more than an exact 1.14MOhm would. The latter causes the distortions not to change between the short location and the central membrane, but the former actually causes the distortion to re-correct the damage done between the short location and the endcap!

Compensating resistance [MOhms]	Distortion on first padrow vs. Z
0.0
1.0
1.14
2.0
4.0
20.0

---

Gene Van Buren
gene@bnl.gov

Observed laser distortions

First look

Second look: dedicated runs

No compensating resistor (run 7076029):

With 1 MOhm compensating resistor (run 7076032), which brings IFC east current to correct value within ~20 nAmps, according to 10:27am 2006-03-17 entry in Electronic ShiftLog:

Again, I looked at the distortion as seen be comparing TPC hits from the distorted runs to those from an undistorted run as I did at the beginning of this page (but this time taking distorted minus undistorted). For the undistored, I again have only run 7061100 to work with as a reference. The plots for each Z are in the second listed attached file below, where the top 6 plots are for the no-compensating-resistor run (7076029), and the bottom 6 are the same ones with the resistor in. I also put on the plots the value of the difference from a simple fit (meant only to extract an approximate magnitude) at a radius of 60cm (approximately the first TPC pad row). Those values are also presented in the following plot as a function of Z, confirming the improvement of the distortion with the resistor in place.

These plots seem to point at a short which is occurring somewhere between the lasers at Z = -145 and -115cm.

Gene Van Buren
gene@bnl.gov

Resistor box at the end of the Field Cage chain

 After ring 181, the potentials are determined by a box of resistors which sit outside the TPC. This is well documented, but at the time of this writing is not complete. This was particularly relevant during Run 9 when an electrical short developed inside the TPC between rings 181 and 182 of the outer field cage on the west end (OFCW). Shown here is a plot of the resistors:

Note that the ammeter is essentially a short to ground, while the voltmeters are documented in the Keithley 2001 Manual to express over 10 GOhm of resistance (essentially infinite resistance). The latter only occurs when the input voltage is below 20 V. The voltages at rings 181 and 182 are above 20 V and below 200 V (though actually at negative voltage), so their voltage is scaled by the shown 1.11 and 10.0 MOhm resistors to be stepped down by a factor of x10. The readings are then multiplied by x10 before being recorded in the Slow Controls database.

After Run 9, this box was disconnected and resistances were measured for the OFCW portion. Because the resistors were not separated from each other, equivalent resistances were actually measured. In the below math, R182eq refers to the resistance measured across resistor R_182, while Rfull is the resistance measured between the input to the box from ring 181 to the output for the ammeter. R111 is the combined 10 + 1.11 MOhm pair.

double R111 = 10.0 + 1./(1./1.11 + 1./10000.)
11.11
double R182eq = 0.533 // measured
double Rfull = 2.31   // measured

double pa = R111 - Rfull
double pb = R111*(R111 - 2*Rfull)
double pc = (R182eq - Rfull)*R111*R111

double R181 = (-pb + sqrt(pb*pb - 4*pa*pc))/(2*pa)
2.3614
double R182 = 1./(1./R182eq - 1./R111 - 1./(R181+R111))
0.5841

double R182b = 1./(1./R182 + 1./R111)

double Vcm = 27960.
double Rtot = 364.44   // full chain
double Inorm = Vcm/Rtot
76.720
double V181_norm = Rfull * Inorm
177.22
double V182_norm = V181_norm * R182b/(R181 + R182b)
33.724

double Rshorted = 1./(1./R111 + 1./R182 + 1./R111)
0.5286
double Rmiss = Rfull - Rshorted
1.7814
double Ishorted = Vcm/(Rtot - Rmiss)
77.097
double V181_short = Rshorted * Ishorted
40.750
double Iexcess = Ishorted - Inorm
0.377

Note that many of these numbers would be different for the inner field cages.

External resistors to make up for missing resistance can also be added to the chain here.

Floating Grid Wire Studies

See PPT attachment for simulations of floating grid wires from Nikolai Smirnov which show that the data is consistent with two floating -190V wires in sector 8, and two floating -40V wires in sector 3 (all wires are at -115V when the grid is "open").

GridLeak Distortion Maps

 Using the code in StMagUtilities, these are maps of the GridLeak distortion.

First, this is a basic plot of the distortion on a series of hits going straight up the middle of a sector (black: original hits; red: distorted hits). The vertical axis is distance from the center of the TPC (local Y) [cm], and the horizontal axis is distance from the line along the center of the sector (local X). Units are not shown on the horizontal axis because the magnitude of the distortion is dependence on the GridLeak ion charge density, which is variable.

The scale of the above plot is deceptive in not showing that there is some distortion in the radial direction as well as the r-phi direction. The next pair of plots show a map of the distortion [arb. units] in the direction orthogonal to padrows (left) and along the padrows (right) versus local Y and angle from the line going up the center of the sector (local φ) [degrees].

One can see that the distortion is on the order of x2 larger along the padrows than orthogonal to the padrows. Also, it is clear that there is a small variance in magnitude of the distortion across the face of the sectors.

The next plot shows the magnitude of the distortion [arb. units] along the padrow at the middle of the sectors vs. local Y [cm] and global Z [cm]. The distortion is largest near the central membrane (Z=0) and goes to zero at the endcaps (|Z| ≅ 205 cm), with a linear Z dependence in between, which flattens off at the central membrane and endcap due to boundary conditions that the perturbative potentials are due to charge in the volume and are constrained to zero at these surfaces.

GridLeak Simulations

Data for STAR TPC supersector.   05.05.2005  07.11.2005
Jon Wirth, who build all sectors provide these data.

Gated Grid Wires: 0.075mm Be Cu, Au plated, spacing 1mm
Outer Sector 689 wires, Inner Sector 681 wires. Total 1370 wires per sector

Cathode Grid Wires: 0.075mm Be Cu, Au plated, spacing 1mm
Outer Sector 689 wires, Inner Sector 681 wires. Total 1370 wires per sector

Anode Grid Wires:0.020mm W, Au plated, spacing 4mm
Outer Sector 170 wires, Inner Sector 168 wires. Total 338 wires per sector
Last Anode Wires: 0.125mm Be Cu, Au plated
Outer Sector 2 wires, Inner Sector 2 wires. Total 4 wires per sector

We are most interested in the gap between Inner and Outer sector, where ion leak is important for space charge. On fig. 1 wires set is shown. The distance between inner and outer gating grid is 16.00 mm. When Grid Gate is closed, the border wires in Inner and Outer sectors have -40V, each next wire have -190V and after this pattern preserved in whole sector - see fig. 2. When gating grid is open, each wire in gating grid have the same potential -115V. Above grid plane we have a drift volume with E~134V/cm to move electrons from tracks to sectors and repulse ions to central membrane. Cathode plane has zero voltage, while anode wires for outer sector holds +1390V and for inner sector +1170V.

Fig. 1. Wire structure between Inner and Outer sector.

Fig.2 Voltages applied to Gating Grid with grid closed.

Another configurations of voltages on gating grid wires are presented on fig.3. All these voltages are possible by changing wire connections in gating grid driver. Garfield simulations should be performed for all to find a minimum ion leak.

Fig.3 Different voltages on closed gating grid (top: inverted, bottom: mixed).

This is a key for Nikolai's files: there are 4 sets of files in each set there is simulation for Gating Grid voltages on last wires. Additionally he artificially put a ground shield on the level of cathode plane and simulated collection for last-thick anode wire and also ground shield and last thin anode wire.

Setups:	Standard	Inverted	Mixed	Ground Strip	Ground Strip and Wire
Equipotentials	PS	PS	PS	PS	PS
Electron paths	PS	PS	PS	PS	PS
Ion paths (inner sector)	PS	PS	PS	PS	PS
Ion paths (outer sector)	PS	PS	PS	PS	PS

GridLeak: Gain Study

First note: the ever-present problem that our model goes to zero distortion at the endcaps, while the measured distortions do not appear to do so (though the distortion curves should flatten out [as seen in the above plots] as a function of Z near the endcap and central membrane due to boundary conditions on the fields in the TPC).

Second note: I have not excluded sector 20 from these plots, which is partly to explain why the east half (z<0) has slightly less distortions than the west in these profile plots. In reality, east and west were about even for a normal run (distortions excluding sector 20).

Here is the z-phi plot for Low (it's almost difficult to see the distortion reduction in the z-phi (in "o'clock") plot for Half):

Third note: (though not too important for this study because we generally ignore east/west comparisons) the sectors between 1-6 o'clock already tend to show somewhat less distortion than the sectors at 7-12 o'clock, and because it is true on both halves of the TPC, it is more likely to be due SpaceCharge azimuthal anisotropy than asymmetries in the endplanes. Here are the distortions at |z|<50 for east (red) and west (blue) as a function of phi in "o'clock" where one can see the already present asymmetry, explaining why sectors 1-6 are already less distorted in the Norm run than sectors 7-12:

We have to normalize to sectors 7-12 to see the drop in distortions as it the runs are taken at different times when the luminosity of the machine, and therefore the distortion normalizations, are different. Here are the ratios from sectors 1-6 / sectors 7-12:

And the double ratios to see the drop in the Half and Low runs w.r.t. the Norm run:

These plots show ratios in the Z = 25-150cm range of about 0.86 and 0.59 respectively, or reductions of about 14% and 41% give or take a few percentage points. Data beyond 150cm tends to be poor and there's little reason to believe that the ratio really changes by much there. However, there does appear to be some shape to the data, which is not understood at this time.

Another way to calculate the difference in distortions is to take a linear fit to the slope of the distortions between z = 25-150cm. Those fit slopes are:

Low:
1-6: 0.000250 +/- 0.000019
7-12: 0.000420 +/- 0.000024
Half:
1-6: 0.000365 +/- 0.000023
7-12: 0.000433 +/- 0.000025
Norm:
1-6: 0.000401 +/- 0.000024
7-12: 0.000422 +/- 0.000023

[Half(1-6)/Half(7-12)] / [(Norm(1-6)/Norm(7-12)] = 0.89+/-0.11 (12%)
[Low(1-6)/Low(7-12)] / [(Norm(1-6)/Norm(7-12)] = 0.63+/-0.08 (12%)
Inner reduction = (11 +/- 11)%
Outer reduction = (26 +/- 11)%
Total reduction = (37 +/- 8)%

Gene Van Buren

SpaceCharge studies

 Studies of SpaceCharge in the TPC.

TPC Sector Alignment Using Particle Tracks for Run 8

TPC Sector Alignment Using Particle Tracks for Run 8

TPC group meetings 2020-

Provide link to minutes of meetings held.

Earlier minutes from during construction and commisioning can be found on https://drupal.star.bnl.gov/STAR/subsys/upgr/itpc/itpc-meetings/itpc-minutes

Started  on 10/14/2020;   but it has not been strictly kept up to date.

March 23, 2023

Friday: East side was finished
from Christian

March 16, 2023

TPC meeting March 16,2023
Present:  Gene, Tommy, Yuri, Alexei, Jim and Flemming

-Hardware
 Alexei complete East laser alignment; Laser system is now ready for upcoming run
 Next week will install ‘new’ magnetic sensors for additional monitoring.
 Q: can these be interfaced to Slow Control (Monitoring)

-    Electronics
-    The TPX s8-3 RDO issue turned out to be a network card problem in the DAQ PC. West is ok a few FEEs are masked off for run
-    East TPC should also be ready.

Gating grid tests
-    Gene is proposing that we test the effectiveness (transparency) of the GG under different beam conditions.
-    Aim to take short runs (<1 min) with 2,3,4,5kHz rate for MB data taking and similar for High lumi running later in the runs.
-    Gene will talk to Jeff on setting up run configs so it can easily be run by crew. And with JG on beam conditions.
-    The equest will be added to the TPC reafiness status

Pre run calibrations
Had long discussion on FF/RFF information that should be extracted. STAR magnet is currently wired for FF.
Yuri would like, now that Alexei has installed detector to monitor possible movement , that we switch a couple of times between FF , 0 , and RFF to see if a) there is a movement and b) if it is reproduceable. This does not need COSMIC data
It was not clear how this knowledge would translate into improved calibrations of TPC. Jim pointed out that (some) E-B mis alignment is already included in space charge distortions (static?). Gene commented that the main geometry calibration issue/uncertainties is related to the super sector to super sector alignment.
Yuri iterated that understanding if there are movements of TPC between FF and RFF will help for calibrations methods.
WWill bring the proposal up at readiness for TPC, but expect to get push back to the ‘cost’ (time, people,..) of doing multiple filed switches.

De/dx calibrations
Yuri pointed to the presentation at last S&C meetins that identified at FF/RFF difference between a correction that has been used previous for de/dx vs. position along wire attributed to wire to pad plane diff. See https://drupal.star.bnl.gov/STAR/system/files/RunXXI%20OO200GeV.pdf

FV raised the issue why this shows up in OO at 200 GeV which has about equal positive and negative charge tracks with opposite curvatures.

+ Run 21 dAu200 SpaceCharge
  - Babu continues to find essentially no asymmetry between east and west, despite historically seeing ~20% more in east
  - Gene sees asymmetry in the lower luminosity Run 21 dAu data, but it disappears at high luminosity
  - Recommendation from Gene was for Babu to process more high luminosity data to help investigate dependencies further

- Run 22 pp500 SpaceCharge
  - Babu has plenty of SpaceCharge work to do even without Run 22, plus his physics analysis
  - Gene has asked the PWGs to provide an additional helper to investigate possible fill-by-vill variations as seen in Run 17
  - Good to educate more people about SpaceCharge anyhow, even if Babu does find  time to work on it

+ New cluster finder
  - Tonko expects it to be not just different, but "better"
  - Tommy proposed a test with embedding to see if momentum resolution and acceptance improves as Tonko hopes
  - Yuri suggests not to focus on momentum resolution, but rather efficiency
  - Tommy will discuss with Tonko more

+ dE/dx adjustments by analyzers
  - Tommy brought up artificial, empirical dE/dx nsigma shifting by analyzers for BES-I datasets
  - Yuri says that's ok as a band-aid for older productions of iTPC era data, but that the new dE/dx model introduced last year should help avoid this
  - Tommy is willing to work on a standard version of the empirical band-aid for people to use, and no one objected

March 9, 2023

February 23, 2023

February 16, 2023

February 9, 2023

Feb 9, 2023 TPC meeting
Present: Yuri, Prahsanth, Alexei, Flemming, Tommy

--hardware
Westpole installed. #d sensor installed before and can be viewed so we can observe movement when filed is turned on, changed polarity etc.
Water leak in East laser box.  Alexei will investigate.

-    After insertion 2 bad FFEs identified. Likely due to squeezed cable. Need to ensure better pre-closure inspection for future years.

Software
  Tommy and Tonko identified one source of differences between online and offline clusters. Namely simulation of hardware asic that merged time sequences separated by just one empty timebin (below threshold) would be merged into one

Yuri reported that analysis of recent survey revealed that TPC is rotated relative to RFF.
Still needs to talk to survey group to understand coordinate systems.

Yuri reported (see meeting page) that the QA plots for pbar vs p vs pt for the period c (production nomenclature) ie. From after covid shutdown is different than before shutdown, Period “” and b .


January 11, 2023

January 4, 2023

December 21, 2022

Present: Alexei, Yuri, Guannan, Tommy, Gene, Flemming, Irakli, and myself

== Hardware
    — survey done on west but not east side
        — Alexei (currently on vacation) trying to push a little to get it done
        — found good way to put cameras for TPC movement
        — Alexei will prepare short presentation upon return == Electronics
    — inner sector RDOs on west side have been put backup by Alexei
    — but on east side some RDOs still need to be returned to proper position         — Alexei needs to talk to Tonko about east side before Tonko resumes work with RDOs on or after 1/1/23

== Software
    — Gene mentions that Babu is still facing some issues on SC and GL
    — PWGs now prioritizing O+O
        — SC is ongoing for that but Babu needs some help from Gene
        — once that’s done will move forward with TPC dE/dx etc.
        — Irakli working on alignment, RFF seems to be converged
            — FF does not seem to be in right place in X after RFF convergence (within 100 um)
    — Yuri finished with dE/dx calibration (7.7 and 9.2 from 2020)
        — have put calibration constants from new model in dB
        — need final check with Standard Library
    — Guannan is continuing work on deep tuning of TpcRS
        — some problems observed
    — Tommy continuing with offline/online cluster comparison
        — 0.5% difference observed and must be understood

December 14, 2022
No meeting, but Yuri presented an update on dE/dx at the s&c meeting  - presentation
Electronics status presented by Tonko at analysis meeting - presentation

December 7, 2022

November 30,2022

November 16, 2022

November 09,2022

November 02, 2022
present:
Gene, Yuri, Tommy, Alexei, Chenlian Jin, Flemming
excused: Richard

Alexei; working on probes for survey.

Open questions cosmics for survey field A/B before run?

Gene: There is no progress on space charge for some BesII years: dAu, 17.6 GeV FXT
Also need for run 22
Will contact Temple.

Nhits issues solved. Will pay more attention to cluster status when selecting/counting cluster distributions

Yuri:
a) will wrap up de/dx model for higher Z. Couple of weeks.
Request that we have a presentations for model before presenting to collaboration.

b) There is interest in making common PID (de/dx,btof,etof,...) for BESII data set from Rice group. Will like to use tpc meetings and e-mail list for this activity.
Suggestions add and invite this group

October 26, 2022

October 19,2022

October 5, 2022

 August 17, 2022

Hardware update,
More on de/dx for 7.7 GeV auau
update from Alexei of TPC electronics readiness

About 2-3 weeks ago we had power dip and since I not paid attention to platform. I found some TPC VME crates and TPC FEE VME were OFF. I powered FEEs from platform(all PS have green LEDs) and control room, everything looks OK, but red LEDs on TPX PCs:   2, 24, 25-36 remained red.

August 10, 2022

minutes

July 27, 2022
Present: Alexei, Yuri, Gene, Tommy, and myself

== Software
 — some slides on current state of dE/dx model work
   — will be updated as work progresses
   — will post slides with current status (keeping in mind there is more to do)
  -- see https://drupal.star.bnl.gov/STAR/system/files/Revison%20STAR%20TPC%20dEdx%20Model.pdf

July 7, 2022
Hardware update. Survey done, Short repaired,
Software de/dx modle update
minutes

June 29, 2022
hardware update. Prepare for survey. Concern for Ar availability
software Tommy,Yuri have been comparing cluster finders offline/online
minutes 

June 22, 2022

Hardware update, survey. TPC electronic speedupgrade, repair  status
software update
minutes

June 15, 2022
Updates on survey plans
minutes

June 8, 2022
Updates on old vs. new cluster finder, simulated charge distribution from fixed target
minutes

June 1, 2022
Updates on dE/dx work, old vs. new cluster finder, simulated charge distribution from fixed target
minutes

May 18, 2022
TPC survey delay, inner sector wires, electronics update, 7.7 dE/dx work
minutes

May 11, 2022
gap measurments, 3D sensor prep work, inner sector wires, electronics update, 7.7 dE/dx work
minutes

April 27, 2022
nitrogen switchover, 3D sensor prep work, spare inner sectors, space charge corr., 7.7 dE/dx work
minutes
 
April 20, 2022
survey results, electronics status end of run, 7.7 de/dx calib done
minutes

April 7, 2022
prep for FF/RFF survey, space charge corr, updated manuals
minutes

February 2, 2022
discussion on added CF4 to TPC, methane shortage, run19 FEE status tables complete
minutes

January 12, 2022
to from run22 submitted, many RDO failures, look at skipping alt row for reco (pp500)
minutes

December 1, 2021
Analysis of shorts, laser response, tpc blower fixed
minutes 

November 24, 2021
Some results from short measurements, Open issues ahead of run, missing Vdrift for a day.
minutes

November 17, 2021
Magnetic field settings reading GG slow control layout, short discussion, variable vdriftd
minutes 

November 10, 2021
Plan for measurements for field cage short, 
minutes

November 3, 2021
West field cage short; run 19 space charge; upcoming calibration issues.
minutes

October 27, 2021
TPC electronics status (Tonko), Laser West repaired, 19.2 GeV space charge nearly complete.GG slow control.
minutes

October 20,2021
hardware status, GG driver, calibration update(Yuri) see slides 
minutes

October 13, 2021
hardware status, cosmic request for run22 startup
minutes

September 22,2021
9.2 TPC space charge cal completed,
Embedding issue for FXT Xianglei discussed. 
minutes

September

September 8, 2021
brief meeting ; hardware cathode control
minutes

September 1, 2021
minutes

August 25, 2021 
NMR status, laser progress
de/dx short term time dependence, helpers for calibration
minutes

August 18  no meeting

August 11, 2021meeting link
agenda: hardware, calibration and software update

December 9, 2020
Agenda:
-hardware status
- software
--- alignment progress 
--- https://drupal.star.bnl.gov/STAR/system/files/he34embedding4th.pdf
--- AOB

meeting link: https://drupal.star.bnl.gov/STAR/event/2020/12/09/tpc-weekly

December 2, 2020
agenda hardware status
meeting link and minutes : https://drupal.star.bnl.gov/STAR/event/2020/12/09/tpc-weekly

November 18, 2020
agenda:
hardware - SF4 tests; laser system
software; 3He efficeincies, track splitting - see talk on meeting event page
aignment progress

meeting place: https://drupal.star.bnl.gov/STAR/event/2020/11/18/tpc-weekly

November 6, 2020
Discussion points:
TPC power cables
Installation of Gating Grid reinstallation
Presentation on 3He efficiencies
Clusterfinder offline vs online
meeting place  https://drupal.star.bnl.gov/STAR/event/2020/11/04/tpc-weekly

October 28, 2020
Discussion points:
hardware: TPC gas investigation; electronics repair
software: GG turnon effects 
meeting place  https://drupal.star.bnl.gov/STAR/event/2020/10/28/tpc-weekly

October 21, 2020
Discussion points:
hardware: gating grid driver
software: Super sector alignment procedure
meeting page https://drupal.star.bnl.gov/STAR/event/2020/10/21/tpc-weekly

October  14, 2020
Discussion points
Hardware: TPX sector 13,14 powersupply cable repairs
Software:  Super sector alignment procedures 

meeting page https://drupal.star.bnl.gov/STAR/event/2020/10/14/tpc-meeting
minutes available on that page

TPC performance

 Documentation on performance of the TPC
 

• Run 15 200 GeV p+Al Hit Errors
• Run 15 200 GeV p+Au Hit Errors
• Run 15 200 GeV p+p Hit Errors
• Run 14 (200 GeV Au+Au) TPC Hit Errors
• Run 14 (15 GeV Au+Au) TPC Hit Errors
• Run 13 TPC Hit Errors (days 74-128) and Run 13 TPC Hit Errors (Days 129 -161) (pp510)
• Run 12 Cu+Au TPC Hit Errors
• TPC hiterrors Run12 U+U 193 GeV
• Run 12 pp510 hit errors
• Run 12 pp200 (before dE/dx calibration)
• TPC Hit Errors (Run11 Au+Au 27 GeV)
• Hit errors for Run11 Au+Au 200 GeV dataset
• TPC Hit Errors (Run11p+p 500 GeV)
• TPC Hit Errors (Run 9), both pp500 and pp200, and re-calibrated TPC hiterrors Run9 p+p 200 GeV RFF
• TPC Hit Errors (2008) (pp200, not certain it was Run 8 or an earlier dataset)

• TPC Pt and DCA resolution

error_xy = sqrt([0]+[1]*((200.-y)/100.)/(cos(x)*cos(x))+[2]*tan(x)*tan(x))
error_z  = sqrt([0]+[1]*((200.-y)/100.)*(1.+tan(x)*tan(x))+[2]*tan(x)*tan(x))

error_xy->SetParameters(0.0004,0.0011513,0.01763);
error_z ->SetParameters(0.00093415,0.0051781,0.014985);

error_xy->SetParameters(0.0012036,0.0011156,0.063435);
error_z ->SetParameters(0.0026171,0.0045678,0.052361);

TPC speed upgrade 2022

TPX high rate test

• Discussion of test plans
• Discussion of test results
• Attached is a slide of the anode currents