[Clas12_rich] May 23th Meeting Minutes
Marco Mirazita
Marco.Mirazita at lnf.infn.it
Fri Jun 3 08:38:41 EDT 2016
Hi George,
in the last days I was busy with the dry run of the ERR presentations
and I didn't have much time to follow the discussions regarding the RICH
gas systems. I realized now that the numbers that are circulating might
be not the right ones.
It is my fault and I apologize for that.
I would make here a summary of the present status of the two systems, as
far as I understood till now.
If there no objections from your side, I consider the numbers that I'm
quoting here as the ones for which we should ask for approval to Bob and
Saptarshi.
We will have time when the RICH will be ready for testing to refine the
parameter of the systems.
1) Cooling system
1.1) Tests in Frascati
We used a mockup of half of the electronic package, heat load 200 W,
cooling system with air flow 100 l/min, air temperature 20 C.
We sent the air flow inside the module using one rilsan tube with 8 mm
external diameter, with a series of small diameter (~1 mm) holes.
The tube must be not too big diameter to avoid heating of the air inside
it.
The holes must be small, to have sufficient velocity of the air to
efficiently cool down the whole volume.
Our gas system was made by a compressor, then a manometer to adjust the
air flux and a fluximeter.
With 100 l/min of air flow, the pressure at the manometer was 0.6 atm.
Just for test, we run also with 200 l/min flow and the pressure was 1.35
atm.
1.2) Cooling system of the RICH
We expect a heat load of 500 W. From the Frascati tests and having some
safety factor, we will need for cooling 300 l/min.
We will send the cooling air inside the RICH using two 8 mm diameter
tubes, one per each side of the RICH module.
Thus, comparing to the Frascati data, we roughly will have 3 times
more air flow but also two tubes instead of one.
As a non expert, I guess we should expect on each side of the RICH cooling
system ends a pressure not much bigger than what we had in Frascati.
Please correct me if I'm wrong on this point.
The exaust will be removed with 6 large diameter tubes.
The maximum capacity of the two compressors has been chosen so that, in
case of failure of one of the two, the other will be able to supply the
necessary cooling air to TWO RICH module.
The system design we have now, with your updated components to sustain
the large maximum flow capacity of the compressors, seems to me correctly
dimensioned to our needs and self consistent.
Why you said in the email below that "This design issue with the RICH is
the limiting factor for electronics air cooling flow and should be
analyzed further." ?
Could you please provide us the drawing of the cooling system with the
updated components?
2) Nitrogen system
One RICH module is about 5 m3 and we foresee one refill per day, which
means about 3.5 l/min.
To avoid contamination in the RICH from external atmosphere, we want an
overpressure of 0.5 mbar. Speaking with Sandro, it seems it could be
further reduced, but, unless strictly required by the system design, I would
not change it for the moment, because we "officially" quoted this number
few times.
Inlet and outlet tubes will be on top of the RICH. We don't have decided
number and size yet, but, given the low gas flow, I don't expect any
particular constraints here. I'm correct?
We discussed about the purity of the nitrogen we are sending inside the
RICH and you confirmed us that the filters you implemented are ensuring
what we need.
>From our side, we would like to have also humidity sensors in the system,
may you add this sensors to your design?
Why having an interlock shutting down the N2 line in case of problems is
not required and will have the opposite effects?
Is the system design we have now able to supply the nitrogen to two RICH
module or just to one?
Best regards and many thanks for your help
Marco
On Thu, 26 May 2016, George Jacobs wrote:
> I will just skip to the chase, so to say. The following RICH design feature will severely limit cooling flow
> to the enclosed electronics package. FYI, my responses are in blue.
>
> --> DSG: The space inside the RICH case is limited:
> we assume to split the 1 inch tube into few
> smaller (9-10 mm diameter) plastic tubes for
> the last part of the line. This may correspond
> to the ~4m from the patch panel till the electronic
> panel. Which is the maximum pressure we should
> aim in this last part of the line ?
>
> How many 4 meter long small ID lines have you determined will fit? Do you have drawings showing the required
> path and connections? I would offer a guess that you will need at least 15 each of the 4 meter long 3/8"
> (9mm) lines to flow 300 slm cooling flow. How many lines can be fit? Typically, using smaller lines in place
> of a larger one requires significantly more space than the single large line would. This is due to the space
> taken up by the tubing wall thickness. At some point, you are basically just filling up the space with nylon.
>
>
> --> DSG: is the current line from tank to RICH
> suitable for maximum 283 slm (due to the
> proposed rotameter) ? How complicate is to
> upgrade it to reach 400 or 600 slm maximum ?
>
> Components have been changed to increase flow capacity;
> 85-850 slm Flow Meter with Manual Valve
> 0-1000 slm Mass Flow Meter
>
> But, in order to increase cooling flow to these higher values, additional numbers of the small ID tubing will
> be needed. This design feature will limit cooling flow capacity and require higher pressure air at the RICH
> box interface for the cooling air supply. I recommend we analyze the space available and design some sort of
> duct to carry the cooling air flow in place of small ID tubing.
>
> This design issue with the RICH is the limiting factor for electronics air cooling flow and should be
> analyzed further.
>
> ------------------------------------------------------------------------------------------------------------
> ---
> ------------------------------------------------------------------------------------------------------------
> --
>
> Now, on to the less exciting topics.
>
> --------------------------------------
> Cooling + Interlock
> --------------------------------------
> The inlet lines are designed for a typical flux of 100 slm,
> and a 1 inch size. This flux was tested in a half-size
> prototype and in a simplified heat load configuration. We
> would therefore suggest to plan a typical 250 slm with a
> large safety coefficient (> 50 %).
>
> Components have been changed to increase flow capacity;
> 85-850 slm Flow Meter with Manual Valve
> 0-1000 slm Mass Flow Meter
>
>
> --> DSG: it would be nice to have the presssure
> sets of the relief valves and the pressure
> regulators visible in the interlock sketch,
> as done for the N2 line.
>
> The Pressure System Engineer has not as yet specified this value.
>
> --> DSG: should the line from compressor to tank
> design to sustain the full compressor flux
> (1200 slm) ?
>
> A high pressure 1" line has sufficient capacity to flow > 1200 slm at pressure
>
>
> --> DSG: do we need an interlock for maximum
> pressure in the tank or in the inlet line or
> everything is set by the relief valves ?
> The compressor has its on interlocked limit.
>
> I do not follow this.
>
> --> DSG: the tank you propose is fine with us.
>
> The interlock logic is relative to the cooling circuit
> functionality. Other anables for the HV and LV power
> supplies should come from temperature sensors in few
> relevant places, i.e. inlet, inner volume, exhaust, FTOF.
>
> The Cooling Circuit Interlocks will prevent HV and LV operation unless the following are true;
> 1) At least one compressor is operational
> 2) Pressure in the air tank is > 80 psi
> 3) Cooling Air Flow > 100 (TBD)slm to the RICH (TBD = To be determined)
>
> --> DSG: may you provide information on your
> board controlling temperature and humidity
> sensors ? We usually use SHT75 sensors form
> sensiron
> --> INFN: should provide detailed information
> in the compressor and power supply
> hardware controls.
>
> --------------------------------------
> Nitrogen line
> --------------------------------------
> We plan to refresh the full RICH volume, close to 5000
> liters, in about one day. The current inlet lines are
> able to provide a maximum of 7200 l/day, with almost a
> 50 % safety factor. We consider it a realistic starting
> point. We would anyway need to minimize the RICH vessel
> leaks.
>
> The LN2 dewar provides a nitrogen with enough purity,
> with a water content smaller than 0.002%. The filters
> are just for safety.
>
> We will need to monitor temperature + humidity with
> sensors inside the RICH volume.
>
> --> DSG: do we need an interlock logic for the
> N2 line, i.e. a shutter to isolate the RICH
> volume in case of problems ?
>
> Not required.
>
> --> DSG: for example we would be in favor to use
> humidity sensors to monitor the inlet line
> quality (the N2 should be fine but we may
> have leaks or breaks in the line).
> May we implement those in an cRio interlock
> logic ?
>
> Not required. Isolating the N2 supply would have the opposite effect.
>
> --> DSG: do we need a interlock shutting the N2
> line in case of over-pressure of the RICH
> module or relief valves would be enough ?
>
> Not Required. The bubbler performs that function.
>
> --> DSG: The RICH N2 inner volume is supposed to stay
> at ~0.5-1 mbar higher pressure than atmospheric,
> to prevent water flowing in. Is the bubble
> control system sensible enough to prevent
> over- or under-pressure ?
>
> The bubbler will maintain pressure according to the oil fill level and acts as a check valve to prevent back
> flow. FYI, 1 milibar = 0.4 inches water column.
>
> --> DSG: the N2 line starts with a LN2 dewar:
> do we need dedicated equipement to prevent
> moinsture along the line and/or injecting
> low temperature gas inside the RICH ?
>
> Not required. The 5,500 liter capacity liquid N2 dewar is located at Bldg 96B, nearly 300 meters from the
> RICH and utilizes a thermal safety valve that prevents cold gas or cryogenic liquid from flowing into the
> house N2 supply lines.
>
> ------------------------------------------------------------------------------------------------------------
> ------------
> ------------------------------------------------------------------------------------------------------------
> ------
>
> I believe this is very good progress and has improved our understanding of the challenges this detector has
> for us.
>
> However, It is very critical that we optimize the electronics cooling flow path at the RICH patch panel and
> inside the RICH box. The current design severely limits cooling flow volume..
>
> Cheers,
> George
>
> _____________________________________________________________________________________________________________
> From: "MMarco Contalbrigo" <mcontalb at fe.infn.it>
> To: "Tyler Lemon" <tlemon at jlab.org>
> Cc: "rossi patrizia" <rossi at jlab.org>, "clas12 rich" <clas12_rich at jlab.org>
> Sent: Wednesday, May 25, 2016 1:27:12 PM
> Subject: [Clas12_rich] May 23th Meeting Minutes
>
> Dear all,
> let me first thanks again the DSG for the essential support they
> are giving to the project.
>
> During May 23th meeting we reviewed various aspects of the RICH
> preparation. Given the readiness review, we are forced to
> converge pretty soon on something realistic. The real working
> considitions will be tested while assembling and may eventually
> require later adjustments.
>
> Below we review the discussed arguments and actions, adding few
> questions we would like to clarify together with DSG.
>
> --------------------------------------
> Components
> --------------------------------------
> Aerogel: forniture will flow on a regular basis. In EEL-121 clean
> room we plan to
> - keep logbook of arrivals
> - store the aerogel inside the dry cabinets
> - perform visual inspection
> - weight the tiles to get the density <--> refractive index
> --> INFN: the scale DSG proposes is fine with us
> - (maybe) check dimensions with a mold
> - (maybe) study optical effects with low-power lasers
> --> INFN: going to supply information on the lasers we
> are using in Ferrara, to check which kind of safety
> regulations they would require at JLab
> We will organize few trips in Washington to measure the
> aerogel transmission. We assume italian personnel will do
> the trip.
> --> DSG: could be available to help in this task ?
>
> Spherical Mirrors: 4 mirrors have arrived at Jlab.
> We are going to open and validate them together with DSG
> starting the week of 13th of June, while we will be at JLab.
> We will concentrate in accepting tests, as likely we will not
> have available all the tools for characterization that week.
> We plan to
> - keep logbook
> - perform visual insepction
> - perform a pointlike-source spot image measure
> - (maybe) perform a Shack-Hartmann surface analysis
> - perform a dimensional check with a CMM machine
> --> DSG: please check availability of the 60 um CMM
> machine in the dates 14-17 or 21-22 June.
>
> Planar mirror: they are being produced, but will be delivered
> at JLab only after the summer.
>
> Mechanics: an assembling test will be performed in Italy
> the first half of June. The RICH module + assembling
> structure will then be transported at JLab. Except for
> storing, no action is foreseen at JLab before enough space
> in EEL-124 will become available (i.e. October).
>
> Electronics: the JLab FPGA boards should have been produced
> already. The production of the adapter+Asics boards will
> start in June. A small quantity will be produced in advance
> to allow a final check before moving ahead with the massive
> production (planned in July). In July Matteo Turisini
> will be at JLab for defining all the procedures and software
> tools, in collaboration with Ben and DSG, for the electronics
> acceptance and characterization. The ideal scenario would
> be DSG will be available to start testing the electronics
> boards in August. In June Paolo Musico will also visit JLab
> and work with Ben to the SSP protocol for RICH.
>
> --------------------------------------
> Assembling
> --------------------------------------
> We plan to perform the RICH assembling in EEL-124 starting
> not before October 2016.
>
> Mechanics: we will mount the RICH case inside the assembing
> structure.
> --> INFN: has to define the bolt size and lift points.
>
> Electronics: it can initially be a stand-alone item. With a
> proper cover of the PMT side, is can run under cosmics and
> allow for daq, slow control and reconstruction tests. With
> the back panel in place it will allow for cooling tests.
> Ideally, we would like to develop/test the same systems we
> are going to use in the Hall. This means power supplies,
> cooling system, interlock system, slow control etc...
> --> INFN: has to discuss with Hall-B management and
> engineers how to best proceed.
>
> --------------------------------------
> Cooling + Interlock
> --------------------------------------
> The inlet lines are designed for a typical flux of 100 slm,
> and a 1 inch size. This flux was tested in a half-size
> prototype and in a simplified heat load configuration. We
> would therefore suggest to plan a typical 250 slm with a
> large safety coefficient (> 50 %).
> --> DSG: it would be nice to have the presssure
> sets of the relief valves and the pressure
> regulators visible in the interlock sketch,
> as done for the N2 line.
> --> DSG: should the line from compressor to tank
> design to sustain the full compressor flux
> (1200 slm) ?
> --> DSG: is the current line from tank to RICH
> suitable for maximum 283 slm (due to the
> proposed rotameter) ? How complicate is to
> upgrade it to reach 400 or 600 slm maximum ?
> --> DSG: The space inside the RICH case is limited:
> we assume to split the 1 inch tube into few
> smaller (9-10 mm diameter) plastic tubes for
> the last part of the line. This may correspond
> to the ~4m from the patch panel till the electronic
> panel. Which is the maximum pressure we should
> aim in this last part of the line ?
> --> DSG: do we need an interlock for maximum
> pressure in the tank or in the inlet line or
> everything is set by the relief valves ?
> The compressor has its on interlocked limit.
> --> DSG: the tank you propose is fine with us.
>
> The interlock logic is relative to the cooling circuit
> functionality. Other anables for the HV and LV power
> supplies should come from temperature sensors in few
> relevant places, i.e. inlet, inner volume, exhaust, FTOF.
> --> DSG: may you provide information on your
> board controlling temperature and humidity
> sensors ? We usually use SHT75 sensors form
> sensiron
> --> INFN: should provide detailed information
> in the compressor and power supply
> hardware controls.
>
> --------------------------------------
> Nitrogen line
> --------------------------------------
> We plan to refresh the full RICH volume, close to 5000
> liters, in about one day. The current inlet lines are
> able to provide a maximum of 7200 l/day, with almost a
> 50 % safety factor. We consider it a realistic starting
> point. We would anyway need to minimize the RICH vessel
> leaks.
>
> The LN2 dewar provides a nitrogen with enough purity,
> with a water content smaller than 0.002%. The filters
> are just for safety.
>
> We will need to monitor temperature + humidity with
> sensors inside the RICH volume.
>
> --> DSG: do we need an interlock logic for the
> N2 line, i.e. a shutter to isolate the RICH
> volume in case of problems ?
> --> DSG: for example we would be in favor to use
> humidity sensors to monitor the inlet line
> quality (the N2 should be fine but we may
> have leaks or breaks in the line).
> May we implement those in an cRio interlock
> logic ?
> --> DSG: do we need a interlock shutting the N2
> line in case of over-pressure of the RICH
> module or relief valves would be enough ?
> --> DSG: The RICH N2 inner volume is supposed to stay
> at ~0.5-1 mbar higher pressure than atmospheric,
> to prevent water flowing in. Is the bubble
> control system sensible enough to prevent
> over- or under-pressure ?
> --> DSG: the N2 line starts with a LN2 dewar:
> do we need dedicated equipement to prevent
> moinsture along the line and/or injecting
> low temperature gas inside the RICH ?
>
>
> Thank you, Marco.
> _______________________________________________
> Clas12_rich mailing list
> Clas12_rich at jlab.org
> https://mailman.jlab.org/mailman/listinfo/clas12_rich
>
> --
> George Jacobs
> Physics Detector Support Group
> Jefferson Lab
> 12000 Jefferson Ave.
> STE 12
> Newport News, VA 23606
>
> (office) 757-269-7115
>
> (cell) 757-876-0480
>
> (email) jacobsg at jlab.org
>
> (website) https://userweb.jlab.org/~jacobsg
>
>
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