[Clas12_rich] May 23th Meeting Minutes
George Jacobs
jacobsg at jlab.org
Thu May 26 10:34:45 EDT 2016
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 supp ly. 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.
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--
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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