Meeting schedule

Every second Monday at 15:30 we have a SeeVogh meeting to discuss the status of the design and production of the Barrel EMC.

The SeeVogh session named "PANDA Barrel EMC" can be accessed with the usual PANDA web password.

Meeting schedule:

• E14 7 Mar 2016 - Online Meeting

April 2019 Sunday Monday Tuesday Wednesday Thursday Friday Saturday   01 Online Meeting 02 03 04 05 06 07 08 09 10 11 12 13 14 15 Online Meeting 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Online Meeting 30

May 2019 Sunday Monday Tuesday Wednesday Thursday Friday Saturday       01 02 03 04 05 06 07 08 09 10 11 12 13 Online Meeting 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Online Meeting 28 29 30 31

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Next Meeting: Online meeting, 12-June-2017

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Minutes of Past Meetings

Meeting: March 7, 2016

Agenda

• stimulated recovery

Participants

• Bochum: Malte, Tom, Mathias, Fritz-Herbert
• GSI: Holger
• Uppsala: Pawel
• Mainz: Luigi
• Giessen: Stefan, Uli, Ben, Christoph, Valera, Rainer, René, Hans
• Groningen: Myroslav
• Bonn: Christoph

Minutes

• stimulated recovery:
  • The crystal recovery in the barrel will be realized with blue LEDs attached at the front edge of the ASIC-PCBs and shining light through the gap between the APDs into the crystal
  • radiation damage in the forward endcap part is high. The required photon flux for recovery is high and might be a crucial parameter when supplying light by fibers

Material:

• barrel-emc-evo-07032016.pdf: slides of meeting from 7-Mar-2016

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Meeting: March 21, 2016

Agenda

• capacitive coupling of HV- and signal ground for HV distribution
• alternative to low side current measurement for HV distribution
• stimulated recovery

Participants

• Bochum: Malte, Tom, Claudius, Fritz-Herbert
• GSI: Holger
• Uppsala: Pawel
• Mainz: Luigi
• Giessen: Stefan, Uli, Ben, Christoph, Till, Valera, Rainer, Hans
• Protvino: Andrey

Minutes

• The capacitive coupling of the HV- and signal ground at the very frontend part of the ASIC PCB still has to be tested in order to guarantee the function of the current measurement of the HV distribution. A larger capacitance value than the currently foreseen was suggested by Pawel, a low ESR is crucial
• an alternative to the low side current measurement on the HV distribution was proposed by Holger (see slides) featuring a high side solution with a current mirror
• stimulated recovery
  • feeding in light for recovery by fiber is crucial. A 30 Gy irradiation can be recovered in 7 h when supplying at least 10e+15 photons/s to the crystal (blue light)
  • some effects in the online recovery are still not understood (Till). A reproducible systematics of radiation damage (dose and dose rate), recovery wavelength, recovery flux and temperature is lacking
  • Malte wants to check, if the mounting of blue 0402 LEDs in the FW-EC inserts are feasible. This would solve the problems with crucial recovery light flux from fibers
  • due to the exponential characteristics of the radiation damage with time, the required recovery fluences might be large for even small radiation doses

Material:

• SP50916032113140.pdf: sketch of APD current measurements from Holger. first page: low side measurement, second page: high side measurement w/ current mirror

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Meeting: April 4, 2016

Agenda

• Reevaluation of number of ADC channels. Utilization of dual/single range FE outputs of different EMC parts
• FE electronics
• APD screening

Participants

• Bochum: Malte, Tom, Claudius, Fritz-Herbert
• GSI: Holger
• Uppsala: Pawel
• Mainz: Luigi
• Giessen: Stefan, Uli, Ben, Christoph, Till, Valera, Rainer, Hans
• Protvino: Andrey

Minutes

• APD screening:
  • Setup for irradiation of APDs to be deployed in 3rd week of April
  • 1500 APDs have to be irradiated and remeasured at GSI for one complete barrel slice
  • estimated throughput for irradiation: ca 320 per week in the beginning with half-sized setup; transportation to GSI still to be planned
• FE output ranges and ADC channels
  • for the BW EMC only one gain per channel is sufficient
  • one possibility to adjust the gain of any channel is adjusting the APD gain. Everybody agreed to not use this method. To operate the APDs at the defined and measured gain/HV settings is prefered to not compromise threshold and resolution
  • the maximum energy deposit is given by gamma-gamma channel as indicated in the TDR. Higher energy deposits could be possible by hadronic channels. A distribution of deposits in dependence of theta angle for heavy targets is still missing.
  • For the theta angles with maximum energy deposits of 1 GeV and below, the utilization of only the high gain channel (HG) is envisaged. The cut in theta between single and dual range readout is still to be identified.
  • The clipping behavior of the ASIC for larger input signals was discussed. Holger explained, that the clipping comes exclusively from the output buffer stage and is not exhibiting long recovery times. The transfer characteristics of the frontend stage is linear over a far larger dynamic range.
  • With a HG amplification factor of 16 a dynamic range of up to 900 MeV can be achieved (provided all other parameters are kept at default, i.e. APD gain=150).
• FE electronics: this discussion point was postponed since Peter was absent due to illness

Material:

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Meeting: April 18, 2016

Agenda

• Reevaluation of number of ADC channels. Calculation of maximum energy deposits in the barrel
• Progress on HV distribution

Participants

• Bochum: Fritz-Herbert, Mathias, Tom
• GSI: Holger
• Uppsala: Pawel
• Mainz: n.a. (excused)
• Bonn: Christoph
• Giessen: Ben, Christoph, Valera, Stefan, Hans
• Protvino: present

Minutes

• The number of dual/single range readout channels was reiterated. Basically, two realistic options were discussed: placing the transition between dual to single range r/o at theate=90° and one at 108°
• Stafan showed the calculations of maxumum energy deposit vs. theta angle.Placing the cut line at 90 degrees would imply to handle at maximum 1 GeV signals in high gain. This would be risky since we would cut off some signals due to saturation.
• The safe solution is to place the transition before the last four modules in bw direction of the barrel (mod types 4 to 7). This corresponds to theta=108°. The max. energy deposit in HG channels would leave a 10 to 20% margin until saturation to compensate for additional gain fluctuations. This solution would lead to a usage of ADC boards in the barrel alone of 630 pcs compared to 710 pcs needed for full dual range readout.
• It was decided by all participants to fix the readout scheme to have a single range readout for the four most bw module rings (2560 crystals) and dual range readout for the remaining barrel (8800 crystals).
• It was also decided unanimously to fix the sampling frequency of the ADCs for the barrel and endcap channels to 60 MHz, since no argument could be brought up to stick to a higher frequency. On the contrary, the frequency content of the signal is well below 10 MHz, placing the chosen 60 MHz sampling rate (including the Nyquist criterion) still at a comfortable oversampling regime without any potential loss of information
• The demand for recording realistic data with the ADCs coming from the APFEL-ASICs including systematic scans was expressed. Myroslav suggested to set up another TRB board for the ADC read out of the PROTO120 in Giessen and connecting this occassion with organizing a presence workshop with all involved/interested groups. The exact date and schedule will be announced soon

Material:

• barrel-emc-evo-18042016.pdf

• sdiehl_energy_limits_for_the_PANDA_EMC.ppt

Meeting: May 2, 2016

Participants

• Bochum: Fritz-Herbert, Mathias, Tom, Malte, Cathrina...
• GSI: Holger excused
• Mainz: Luigi
• Giessen: Till, Christoph, Stefan, Hans, Lars joined us at a visit in Giessen

Minutes

• Review of decisions from last meeting: cut between dual/single range r/o at theta=108°, last 4 module rings with single range r/o, this saves 80 ADCs (from 710)
• Myroslav wants to wait for the confirmation of a definite ADC sample rate until the rad hardness test of the ADC FPGAs; if successful the ADCs then could be operated at 40 MHz sampling frequency at the benefit of halving the ADC price (or the total number of ADCs?)
• Bochum TRB board could be ready to be brought to Giessen for a lab setup with PROTO120, SFP-Plugin cards are available. Giessen will consider borrowing another TRB board from another PANDA group afterwards
• APD irradiation setup was installed and connected in Giessen at the irradiation facility. Cooling down to -25°C works flawlessly. However, The change of the APDs at a cooled down setup is impossible due to massive ice and water condensation. The APD cassettes are impossible to open unless warmed up to at least +15°C
• Suggestion: Irradiation will be conducted at -25°C as planned. After the end of the irradiation, the setup should be warmed up (still in closed condition) to above dew point. After some time (still to be fixed) of dry air flushing the cassettes may be opened and the APD grids switched. After cooling down to -25°C the new irradiation cycle can be started
• Bochum (Mathias or Tom) pointed out that irradiations of APDs were done at KVI and Jülich. At the obtained fluences no significant effects were observed. A summary of the irradiations and the fluences will be provided by Bochum soon
• A time plan for the barrel slice assembly is to be worked out asap. Until the end of the year all modules (18) have to be equipped, i.e. all 1500 APDs have to be provided soon.
• A barrel slice assembly planning meeting will be announced within the next days which should take place before end of May. All involved groups should participate at this meeting and are asked to work out a preliminary schedule of their work tasks and availabilities as a basis for this meeting.
• A new prototype of a 4ch HV distribution PCB was produced and is being soldered at the moment. The formfactor of 57x55mm already corresponds to the final footprint of the backplane PCB

Material:

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Meeting: May 30, 2016

Agenda

• Barrel Slice Assembly planning, Request for work plans of participating groups
• Progress on HV distribution
• Status of APD irratiation and alternative irradiation scenario

Meeting: June 27, 2016

Agenda

• Status of Barrel Slice Assembly

Material:

• slice-planning.ods: Time table of slice assembly steps and procedures
• CAD Drawing of mounting plate with potential drill holes for PCB mounting, Nr.1:
  

• CAD Drawing of mounting plate with potential drill holes for PCB mounting, Nr.2:
  

-- HansGeorgZaunick - 27 June 2016

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Meeting: May 15, 2017

Agenda

• APD irradiation setup
• Reflectors for fiber coupling
• Backplanes
• Barrel design

Participants

among others:

• Bochum:Fritz-Herbert, Tobias
• Giessen: Stefan, Valera, Markus
• Protvino: Andrey

Minutes

• APD irradiation setup:
  

  • Andrea mentioned to Markus on the phone: reference Grid monitors only the source height. No cooling and no precise position except the height is necessary.

  • Setup will be extended soon according to these requirements. The Design is ready

• Reflectors for fiber coupling:

  • Reflective coating inside increases amount of light from fibers into the crystals by a factor of two.

  • With reflective coating, the expected efficiency for the worst case scenario (most backward region) is in the order of 0.5%.

  • Bochum will send soon the latest light pulser system to Giessen. The deposited energy equivalent of its pulses through the Reflectors need to be specified.

  • Andrey: Valeri will check if there is enough space to loop the fibers in order to avoid the worst case scenario.

• Backplanes:

  • Present form factor wont fit into the bottom of the support beam at the most forward direction due to its tapered shape.

  • The in summer available Flex-PCBs will be to short for an elevated board position.

  • Andrey asked Markus to send all present dimensions of electronics including Flex-PCBs to Valeri.

  • Giessen considers a redesign of the boards. This will take some time and the routing of all Flex-PCBs have to be known in advance.

• Barrel design:

  • Changing the barrel design into independent sectors for a better maintenance demands, among other things, an increased cryostat.

  • Presently Andrey is in contact with Novosibirsk. It is expected, that the necessary cryostat budget will increase by a factor of two.

-- MarkusMoritz - 29 May 2017

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Meeting: June 26, 2017

Agenda

• APD irradiation
• Assembly tools
• Electronics

Participants

among others:

• Bochum: Malte, Tobias
• Giessen: Markus

Minutes

• APD irradiation:
  

  • Malte mentioned, Giessen should have received some new APDs for irradiation. This is not the case so far.

• Assembly tool:

  • Due to the limited maximum crane height, it was decided to lower both tables down. The XY Table is now revised and ready. The slice Assembly table is right now in the workshop

• Electronics:

  • Giessen has produced dummy cables with similar diameter of the designated BADE signal cables to test the size of the available window in the support beam. The Test will be done soon

  • Peter Wieczorek announced vie email, there might be news about ASIC tests, board developments, Samtec ect. on the next on-line meeting in two weeks.

  • Bochum needs to know the positions of the temp. sensor adapter boards. Their positions are not yet fixed.

-- MarkusMoritz - 26. June 2017

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Meeting: July 10, 2017

Agenda

• APDs
• ASCIs-FlexBCBs

Participants

among others:

• Bochum: Malte, Tobias, Mathias
• Giessen: Markus, Hans, Stefan, Marcel

Minutes

• APDs:

  • PSL raw data is in Bochum available.

  • Development of automated validation software is almost finished.

  • In most cases of the very few APDs which did not pass the automated validation process, it seems, that the measurement process itself has some issues.

  • Due to the availability of the raw data (before irradiation) and the lack of time, it should be considered to start irradiation of all APDs right now, even without finished data evaluation. If necessary, the corresponding APDs can be sort out after irradiation.

  • Gießen reminds again the risk of a possible shut down of the radiation facility.

• ASICS-FlexPCBs

  • Presently the devices are in the US for assembly.

  • Then they have to be equipped with missing capacitors and connectors in Giessen and finally tested at GSI.

  • It is expected, that all ASICS are ready for mounting around September.

-- MarkusMoritz - 10. July 2017

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Meeting: September 18, 2017

Agenda

• ASCIs-FlexBCBs
• APFEL-ASICs
• HitDetection -ASIC
• ADCs
• Slice assembly
• APDs

Participants

among others:

Mathias, Fritz-Herbert,Markus, Hans, Marcel, Andrey R., Holger, David, Luigi

Minutes

• ASIC-FlexPCBs:

  • It is expected, that all necessary APFEL-ASICS-FlexPCB-units will be delivered end of September.

  • After delivery 6 further weeks are needed for tests and final assemblies.

• APFEL-ASICs

  • It is not trivial to find perfect baseline working levels for differential driver. Fortunately, all ASCIS should behave very similar. Only minor adjustments have to be performed.

• HitDetection-ASIC

  • Input stage is optimized for APFEL-ASIC signals.

  • Currently a Master Student characterizes the H.D.-ASIC

  • ADC stage is already tested.

  • In 3-4 weeks the chip could be able to read out crystals

• ADCs
  • Large fraction of EMC power consumption due to 100 ohm signal cable termination. Proposal: suitable buffer with capacitor termination. This idea has to be discussed with Pavel.
• Slice Assembly

  • Assembly of super modules and first slice is expected this year.

  • So far there is no insulation between super modules and support beam available.

  • After the (test-)assembly, the support beam can be dismounted for an upgrade with insulation material.

• APDs

Everybody agreed bias during irradiation is not necessary. So far, no effects have been observed.

APD irradiation procedure needs to be discussed in detail during the forward endcap online meeting next Monday, due to new boundary conditions and the upcoming PRR.

-- MarkusMoritz - 21.Sep. 201

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Meeting: October 02, 2017

Agenda

• ASCIs-FlexBCBs
• HitDetection -ASIC
• ADCs
• Slice assembly
• APDs

Participants

among others:

Pavel, Holger, Tobias, Thomas, René, Markus

Minutes

• ASIC-FlexPCBs:

• • Announced delivery in week 40

• HitDetection-ASIC

• • GSI have now support from Mainz

  • First characterizing results promising

  • Test of analog memory will begin this week

  • Foreseen sampling freq. 100 MHz

  • Present test setup has very limited readout speed

  • Timescale: if everything works fine, there could be a full scale prototype end of next yeary

• ADCs

  • Pavel waiting for ADCs

  • Prototypes have to be tested before assembling batches

• Slice Assembly

  • VIP panels for the front insulation have been delivered today

  • Now the price for each is much cheaper than during the order for the end-cap, therefore one can consider to use these VIPs for the sidewalls of a slice test-setup.

• APDs

  • 108 Grids are now in Giessen

  • 29 of the 108 are PSL validated and have clearance for irradiation.

-- MarkusMoritz - 05.10.2017

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Meeting: October 16, 2017

Agenda

• Mechanics
• Crystals
• Front-End

Participants

among others:

David, Marcel, Andrey R., Pavel, Fritz-Herbert, Tobias, Luigi, Myroslav, Markus

Minutes

• Mechanics
  • All barrel modules between -3 and +3 will be send to Giessen this year

  • In case of a delayed crystal production a barrel version with some empty slices (without any modules) is preferable. All other solutions will lead to serious problems.

• Crystals
  • Swedisch money for SADCs will be redirected to crystal production.
• Front-End
  • Hit-Detection ASICs are considered instead of SADCs

  • Advantages and disadvantages should be discussed in a dedicated SADC/Hit-Detection-ASIC meeting.

-- MarkusMoritz - 01 Nov 2017

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Meeting: May 14, 2018

Agenda

• Mechanics

Participants

among others:

Marcel, Uli, Andrey R., Fritz-Herbert, Thorsten Erlen, Malte, Tobias, Markus

Minutes

• Mechanics

  • All parts of the modules and super modules official accepted by Giessen.

  • All temporarily imported barrel tools still sitting in Giessen. They are needed in Russia for the mass production of the accepted parts. There are ongoing bureaucracy issues between FAIR, IHEP and all involved customs. No furter barrel modules between -3 and +3 have been seend to Giessen so far.

  • The support-beam is now mounted on the first slice. It was figured out, that the design could be improved.

    • The behavior and therefore possible routing schemes of the FlexPCBs were completely unknown during its design process. Therefore, the positions of the feed troughs for the FlexPCBs are not optimal. Many FlexPCB do not go perpendicular from the super modules into the support-beam. This could cause problems with the thermal insulation, the needed airtightness and the necessary length of the FlexPCBs.

    • Furthermore, the mounting of the back-planes inside the support-beam seems to be complicated, even with longer FlexPCBs and against the background that the available space is very limited.

    • One idea was to reduce the thick bottom of the aluminium support beam down to a framework consisting only of some (thick) bars for the thermal insulation feeds. The rest of the bottom could be filled with thin plastic mounting rails or plates. This will create more space for the electronics inside, makes the FlexPCB routing much easier and has for the thermal insulation the advantage, that there is less material with good conductivity. Thorsten tries to make a rough draft of this idea.

  • Nevertheless, it was decided to try to install the insulation and connect as much as possible detectors with the present design and decide afterwards how the support-beam should be improved.

    • The needed FlexPCB length for the present support-beam design should be determined.

    • The support-beam have to be removed within the next couple of weeks for installing the cooling-pipes and insulation as far as possible.

  • There is a proposal to make the inner-side of the barrel air tight by using a large and thin cylinder.

-- MarkusMoritz - 15 May 2018

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Meeting: June 25, 2018

Agenda

• Mechanics
• Cooling
• APDs
• Annealing LEDs

Participants

among others:

Andrey R., Thorsten, Cathrina, Matthias Hans, Markus

Minutes

• Mechanics

  • The bureaucracy issues between FAIR, IHEP and all involved customs have been solved. The boxes with tools ect. arrived at IHEP.

  • In order to optimize the routing of the FlexPCBs , a test segment of the support-beam have been build in Gießen. It sits above super-module 3 and will be mounted soon.

  • It is foreseen, that the IHEP colleagues will visit Giessen at least in 2019 to teach the mechanic shop all necessary steps for the complete slice assembly

    • All drawings have to be fixed for this date and sufficient Crystals with APDs have to be ready

    • In 2018 another visit from IHEP to Giessen has to be scheduled for several reasons.

Cooling

• • The pipes are nearly ready in Bochum.
  • Needed mounting clamps will be availible next week.
  • So far, no suitable cooling-machine is available. The available one can not use water-ethanol mixture.
• APDs

  • APDs will be handled in packages of 30 pieces.

  • A throughput of 250/APDs per week are intended

  • Gießen will design multipurpose boards for optimized handling during irradiation, annealing and transportation. Nevertheless irradiation and annealing can be performed without these

• Annealing LEDs

  • Six ASIC-PCBS with LEDs assembled in Mainz

  • Annealing-test-setup for crystals @ -25°C needs to be defined.

  • The following has to be checked in advance: Noise with LED pin open and pin grounded. The line could be a nice antenna

-- MarkusMoritz - 26 June 2018

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Meeting: August 20, 2018

Agenda

• Mechanics & Cooling
• Readout
• APDs

Participants

among others:

Matthias, Thorsten, Cathrina, Thomas, Markus, Hans, Luigi

Minutes

• Mechanics & Cooling

  • There is a proposal to use the fixture for the backplanes to seal the openings in the support beam bottom. Each Backplane package will get an adapter with an rubber washer. This concept has to be tested.

  • A water cut thermal insulation layer between the super-modules and the support-beam is ready. Their openings for the FlexPCBs have to be manually insulated after its installation.

  • There are concerns due to the reduced space around the target pipe. It is unclear how much space will be left for all the necessary cables coming from the downstream part of the corresponding two slices.

  • The necessary bending radius for the inner u-shaped cooling pipe on top of all super-modules within one slice seems to small to realize. An alternative solution might be needed here.

  • The dry gas flushing concept has still to be developed. So far, it is foreseen that the inlet will be in front and the outlet behind the crystals.

• Readout
  • No improvement of a square-root of two was seen by summing up the signals of two APDs in past experiments using ASIC readout. The reason might be, that a correlated noise occurred always. Proper shielding did not help.

  • In general, a digital filter, implemented in the SADCs, seems to produce very promising results.

• APDs

  • 250 APDs have been processed in Gießen according to the new procedure for the forward endcap. Conductive foam was used during irradiation and annealing (48h).

  • A first multipurpose PCB is now available and will replace in the longterm the conductive foam and the transport boxes.

-- MarkusMoritz - 22. Aug 2018

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Meeting: Sebtember 3, 2018

Agenda

• Mechanics
• Hit.Det. ASICS

Minutes

• Mechanics
  

  • A first version of the design of the Backplane adapters are ready. Gießen currently produces an overpressure test setup.

  • For the light pulser monitoring system of the most backward crystals, small prism are again considered. All other cheaper concepts delivered no promising efficiency in “getting the light around the corner”.

• Hit-Det. ASIC
  
  • Oliver analyses out-coming data form a Hit-Det. ASIC circuit simulation.

  • A revised Chip will be available end of this year.

-- MarkusMoritz - 13 Sep 2018

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Meeting: October 29, 2018

Agenda

• Mechanics
• APFEL-ASICs

Participants

among others:

Luigi, Thorsten, Fritz-Herbert, Tobias, Uli, Pavel, Markus

Minutes

• Mechanics
  • This week colleagues from IHEP are in Giessen to discuss certain design details. Those are for example: support beam design, colling, mounting of the backplanes
  • On wednesday Thorsten from Bochum will join the discussion.
  • First tests of the backplane adapters with an overpressure are promising. Currently different sealing materials are tested.

• APFEL-ASICs
• ​New PCBs with packaged ASICs and annealing LEDs are available in Mainz.
• They were tested within a small test setup consisting of a full read out chain attached to a crystal and a light pulser (fiber) inside an aluminium box.
  
  • First data taken with the following LED configuration: LED connection open (A), short (B), connected to voltage supply (C).
    • Only one of the two APDs showed a slight increase of noise in case of (C).
    • The pulse height spectra showed no differences within statistical fluctuations.
    • Reproducibility will be checked.
  • The electro magnetic compatibility should be checked for (A),(B),(C). It is yet unclear if the LED could be an additional antenna. Giessen has access to an emc chamber at the university of applied sciences.

-- MarkusMoritz - 30 Oct 2018

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Meeting: January 21, 2019

Agenda

• Mechanics
• Serial-Adapter-ASIC
• Cooling

Participants

among others:

Minutes

• • Mechanics

    • Proposal for Backplane mounting inside the sup.beam: use on bar perpendicular to the beam instead of individual Backplane adapters. Could result better sealing of support-beam openings. The design would need a couple of hours manpower.

    • A team from IHEP will visit Gießen in mid of February to test and modify a new support beam design. They bring soft mock up plates for first tests and further modifications if necessary. After this Gießen will produce stiff segments of the support beam bottom according to the outcome of the visit. With those, a full assembly including backplanes will be tested once more.

    • During the IHEP visit, the bending of the slice will be measured in the xy-turning table as well. As preparation, the mounting of the technological beam will be tested in advance by Gießen.

Serail-Adapter-ASIC

• • • Tests are promising so far. All functions seems to work except the DAC. The following solutions have been discussed

      1. use dig-converter external → not enough space on backplane

      2. create luck up tables for each DAC → very resource intensive

      3. new iteration of DAC → prototypes could be available in August

      4. switch to current DAC instead of one which regulates Voltages

    • Option 3 was in favor of everybody in the end

  • Cooling System

    • Fitting of pipes with larger diameter will be evaluated. The cooling liquid flow could be not sufficient with the present diameter

-- MarkusMoritz - 25 Jan 2019

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Meeting: February 4th, 2019

Agenda

• Mechanics
• Cooling
• APDs
• Electronics

Participants

among others:

Thorsten, Andrey, Fritz-Herbert,Markus, Hans, Luigi

Minutes

• Mechanics
  • Concerning the scheduled visit of a Group from IHEP to Giessen there have been some open questions raised which should direct addressed via Email to Valeri Ferapontov (not present). Those were for example:
    • In the drawings of Technological beams are some kind of brackets drawn to fix this beam to the xy-turning table. Are those necessary? They are not existing at the present beam.
    • Currently there are M18 bolts available for fixation in Giessen. Are they sufficient? Thicker ones have to be ordered.

  • Giessen got an nice offer from the company Hexagon to measure the slice deformation during rotation. The IHEP Group likes to join the measurements. Therefore, it is being tried to settle the 18. February or the 15. February for those measurements.

  • There will be an installation workshop at GSI in two weeks. There is in principal nothing new to show from the barrel side. Nevertheless one should clearly communicate again our point of view, that a barrel upgrade will be a very complicated and dangerous task.

  • For the barrel assembly inside the experimental hall one day per slice will be needed minimum. It is unknown or not predictable how time consuming all the cables and houses would be.

• ​Cooling

  • Measurements showing that any sealing material, like rubber or foam, won't be good enough to close the openings in the support beam for the FlexPCBs with the current backplane-adapter design against the inner overpressure of each slice. An alternative solution could be glue. Loctite (Henkel) offers a silicon based glue, formulated for nuclear plants. It has to be tested, if the adhesive force could destroy the FlexPCBs during dismounting for example. Nevertheless, it has to be discussed which criteria could lead to such a need later on. The risk of destroying other detector components, independent of using glue or sealing material, is very high. This topic should be discussed during the upcoming assembly workshop at GSI.

• ​APDs

  • Giessen like to get at least 9 matched pairs from the current screening procedure from Bochum to assembly another prototype for several tests. 25 pairs would be the ideal case. Realistic time frame for delivery might be 1-3 weeks.

  • Concerning the transportation of all remaining APDs from PSL to Gießen, Andrea wants to get in contact with Markus end of this week.

• ​Electronics

  • The Samtec delivery of signal cables with an ultra low cross-section arrived at Giessen

  • The announced delivery time of 45 ordered SADCs in Nov. '18 amounts 17 weeks.

-- MarkusMoritz - 05 Feb 2019

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Meeting: March 4th, 2019

Agenda

• Mechanics
• Cooling
• Serial Adapter ASIC
• PANDA Prototype Test
• SADCs
  

Participants

among others:

Thorsten, Andrey, Fritz-Herbert, Hans, Pawel, Holger, Markus

Minutes

• Mechanics
  • A Team form IHEP visited Gießen recently for a next iteration of the support beam design and to perform stiffness tests of the whole slice.
    • By using a full set of dummy sheets representing the full support beam bottom, it was figured out, that the design reached not yet the an optimum state during that visit.
    • According to those findings another design iteration was showed and discussed in this online meeting, which still have some issues.
      • The Backplanes have an even numbers of sockets for the FlexPCBs. This causes an alternating left-right arrangement of the Connectors on the FlexPCBs. The slice has an odd number of crystal rows, so there have to be one row which do not follow the left-right pattern. At the moment this bachelor row is put in the middle region. It seems, that this position demands a special backplane sandwich with half of its size due to space problems. Such a backplane can not be realized, because there are a couple of components necessary independent of the number of attached FlexPCBs. A shift of this bachelor row to the most downstream area will be investigated.
      • Above the Modules 2-3-4, there is at on place not enough space for one row of backplane sandwiches. Here, the boards are overlapping with the boards of the next rows. A complete but slightly rearrangement of all backplane positions will be investigated.
    • The stiffness and dimensional stability was measured in the assembly room inside the XY turning table by an hired external metrology company. A couple of rotating positions have been investigated. The analysis is expected within the next working days.
  • There was again the question if we have to use the existing preseries support beam for all test and to try to adapt as good as possible all the electronics for this or if there will be a modified support beam, even for the first slice.
    • Gießen is designing all electronics and fixation adapters with respect to a modified support beam as it will be used later on for the barrel.
    • The workshop of the University Gießen can create further segmented support beam mock ups until the redesign process is finished. IHEP will provide drawings.
    • IHEP will discuss internal this tuesday if they can provide a new (final) support beam for the first slice. Nevertheless they need 16 support beams at IHEP to test the assembly of the barrel.
  • A delivery of alveoles and a couple of further mechanic parts like inserts to Gießen is scheduled for this May.
• Cooling
  • In order to start the mass production of supermodule plates, thermal insulation feets and redesigned support beams the mechanics have to be tested together with the cooling.
  • So far the mechanical design should be fine concerning the boundary conditions for the cooling . The cooling is or will be designed around the existing design. There should be no changes necessary.
  • New cooling pipes with respect to an increased coolant flow are currently produced in Bochum. It is expected, that those will be ready end of this week.
• ​Serial Adapter ASIC
  • All features of the first Version have been tested now. They seem to be fine except a bit-shift in its answer and a nonlinear DAC was observed.
  • Holger will try to reproduce such behaviors in the Simulation.
  • The next iteration submission deadline will be in April.
• ​PANDA Prototype Test
  • There will be a beamtime in May at MAMI Mainz
  • The full readout chain of the barrel will not be ready until this date, therefore Mainz will provide a backward-endcap-testmatrix.
  • It is foreseen to damage the crystals with the accelerator to study the response function and the annealing dynamics with the LED on the APFEL-ASIC.
  • In order to quantify the dose of the crystals Gießen will provide a set of crystals with individual LY loss vs dose curves. With the application of the light pulser system the accumulated dose can be obtained.
  • Nevertheless, Bochum will provide Gießen a set of characterized APDs for a future Prototype with the full and hopefully final readout chain of the barrel.
• ​FlexPCBs
  • During the redesign process of the support beam it was figured out, that all FlexPCBs are long enough or even to long. A final statement can only be given after the support beam has reached the final design status.
  • Mainz orders 700 FlexPCBs until end of this year for the backward endcap. It was pointed out, that this order should be done complete independent from the barrel.
• SADCs
  • The current order of SADCs have been produced with a not suitable design for the APFEL ASIC. They will be send back to the producer for modification.

-- MarkusMoritz - 05 Mar 2019