[Clas12_rich] Fwd: Re: May 23th Meeting Minutes
Marco Mirazita
Marco.Mirazita at lnf.infn.it
Wed Jun 8 11:30:24 EDT 2016
Hi Saptarshi,
here some additional information.
- the max. pressure we may have in the system is the pressure of the
tank, 8 bar
- the rilsan tube we plan to use inside the RICH has a working point of
15 atm, see the attached document, page 5, RILSAN PA 11 - PHL, cod. 8x
10
- I don't know what type of 1 inch tube are routinely used at JLab, but
according to George they can sustain the 8 bar.
- we made a rough calculation of the pressure drop on the circuit
considering 8 mm diameter and the air flow we want, the estimate is of
the order of 0.1 kPa per meter, i.e. few pct of atm after 20 m
Best regards,
Marco
Il 2016-06-06 19:42 Saptarshi Mandal ha scritto:
> Marco,
>
> Thanks for all the information. This will surely be helpful. I'm
> assuming someone in your group has already done the cooling system and
> pressure drop calculations.
>
> Also could you send me the max. allowable pressures in the tubing that
> you have selected? The 1 inch tube and the rilsan tubes.
>
> Thanks.
> Saptarshi
>
>
> On 6/6/2016 1:09 PM, Marco Mirazita wrote:
>> Dear Saptarshi,
>> George sent to you the updated drawings of the RICH cooling and N2 gas
>> systems, from the sources up to the panels just before the RICH.
>> Here I want to add some information on the circuits from the panels
>> and inside the RICH, in order to allow you to fully review the systems
>> and to be able to approve by June 10.
>>
>> Cooling system
>>
>> We have 1 inch tubes in the system, from the compressors to the panel.
>> From the panel, each tube serving one RICH module is split in two, I
>> don't have the map of Hall-B but I guess their length should be
>> something like 10 or 20 m.
>> The air is sent inside the RICH through two rilsan tubes (one per side
>> of the RICH) with 8 mm diameter. They run inside the RICH from the top
>> panel to the electronics (see the pictures) for about 4 m.
>> The exhaust air is removed by 6 large tubes, 30 mm diameter.
>> The system includes two compressors with max capacity of 1200 l/min,
>> to be able, in case of failure of one compressor, to serve both
>> modules with the other.
>> The maximum pressure in the tank is about 8 bar.
>> The operating point is to have 150 l/min of air per side (300 l/min
>> per module).
>> The system George designed is dimensioned to sustain the max. flow the
>> compressors could supply, even if it is much higher than what we need
>> and we will never run at this high flow rate.
>>
>> Nitrogen
>>
>> Again, we have 1 inch tubes from the N2 source to the panel.
>> The gas inlet is on one side of the RICH, the outlet is on the other
>> side.
>> Again, we need to split the 1 inch main tube to the 5 inlet rilsan
>> tubes, with variable length between about 1 and 4 m, that run inside
>> the RICH.
>> The outlet is made by 2 large tubes, 30 mm diameter.
>> The working condition is to have one refill per day, which means 3.5
>> l/min, with a maximum overpressure inside the RICH of 0.5 mbar.
>>
>> Best regards,
>> Marco
>>
>>
>>
>> -------- Messaggio originale --------
>> Oggetto: Re: [Clas12_rich] May 23th Meeting Minutes
>> Data: 2016-06-03 21:09
>> Mittente: George Jacobs <jacobsg at jlab.org>
>> Destinatario: Marco Mirazita <Marco.Mirazita at lnf.infn.it>, Bob Miller
>> <rmiller at jlab.org>, Saptarshi Mandal <mandal at jlab.org>
>> Cc: Marco Contalbrigo <mcontalb at fe.infn.it>, rossi patrizia
>> <rossi at jlab.org>, clas12 rich <clas12_rich at jlab.org>
>>
>> Hi Marco,
>>
>> I will answer the questions I can. But, your design of the detector
>> internal cooling should be approved by Hall B and JLAB engineers. Same
>> with the details of your external piping and cable connection
>> locations.
>>
>> For 1.1, 1.2, and 2.0 you should direct your questions to Bob Miller
>> and Saptarshi Mandal about your plan to use a 4 meter long 8mm OD tube
>> to flow 150-300 slm air. FYI, the smaller the tube ID and the longer
>> the tube length, the higher the pressure required to flow X liters of
>> gas. Larger ID gas lines and/or a greater number of lines will flow X
>> liters of gas at a lower differential pressure.
>>
>> Hall B engineer must approve the physical locations of the air and N2
>> input and output line connections. I am unfamiliar with your detector
>> design, but I am pretty sure all connections must be at the back
>> plate. Not sure what you mean by the top of the detector. Bob Miller
>> can explain the exact physical constraints.
>>
>> Please find that I have attached 4 diagrams. 2 for the air cooling
>> circuit and 2 for the N2 purge. Please take a close look at the flow
>> paths, components, and connections. Perhaps these diagrams will answer
>> many of your questions. Perhaps a meeting should be scheduled where
>> these diagrams can be discussed at length? But, not a phone meeting.
>>
>> Your questions;
>> 1)------------------
>> MM question- Why having an interlock shutting down the N2 line in case
>> of problems is not required and will have the opposite effects?
>>
>> GJ response- What exact purpose or problem would be solved by adding
>> an automatic shut off valve for stopping the N2 flow? What danger or
>> hazard is mitigated? What parameter is to be monitored for the
>> interlock?
>>
>> Any powered shut off valve would close in the event of a power outage.
>> That would shut off N2 flow to the detector. Long term power outages
>> are associated with storms such as hurricanes and other rain events
>> with wind and flooding. During these events humidity in the hall will
>> increase to 100%. In the case of power outage the shut off valve will
>> stop the N2 gas purge. This will allow H2O into the RICH.
>>
>> In my current design, see the attached diagram, the N2 purge flow does
>> not stop during a power outage. The N2 purge continues preventing H2O
>> from entering the RICH.
>>
>> 2)------------------
>> MM question - From our side, we would like to have also humidity
>> sensors in the system, may you add this sensors to your design?
>>
>> GJ response - I can add H2O sensor to the N2 supply if you want one.
>> Is there any particular location you want it at? Or would you prefer
>> it on the outlet to measure the H2O in the N2 exhaust gas?
>>
>> 3)--------------
>> MM question - Is the system design we have now able to supply the
>> nitrogen to two RICH module or just to one?
>>
>> GJ response - Please look closely at the supplied diagrams for the N2
>> controls and N2 Valve panel. You will see that there are 2 identical
>> gas supplies, one each for the two RICH detectors. The diagrams name
>> them as RICH #1 and RICH #2.
>>
>> 4)----------------
>> MM question - What is the nitrogen quality?
>>
>> GJ response - Nitrogen quality is 99.998 % pure. That leaves 20 ppm
>> of other stuff. According to the vendor, it will always be <3 ppm H20.
>> If this quality is less than required, we will need to use ultra high
>> purity N2 from high pressure gas cylinders using new dedicated gas
>> supply lines that run from outside the hall to the fwd carriage
>> location of the RICH gas panel. This would increase the daily cost of
>> the N2 purge gas significantly.
>>
>> Cheers,
>> George
>>
>> On 6/3/2016 8:38 AM, Marco Mirazita wrote:
>>> 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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