[Dsg-rich] URGENT: RICH alarm

Wed Sep 19 08:25:17 EDT 2018

Good morning All, 

     I am in complete agreement that this is excellent information but it brings to light the potential for major unexpected problems.
Historically the detectors, targets, magnets, vacuum systems and other components in Hall B have all been designed to fail "safe" in the 
event of any system failure. Through interlocked valves, reliefs, circuit interrupts or other fast shut down devices, they are all designed 
so that any foreseeable problem will be mitigated without the possibility of damaging the equipment. I am not in anyway trying to insinuate 
that the RICH detector is an exception to that design but that it is a much more sensitive detector when it comes to operation. This is 
evident from yesterday's interruption in nitrogen flow. Even though it was brief and controlled it obviously had a definitive impact on the detector. 
Hall B's nitrogen supply is used in countless operations throughout the Hall and is frequently tapped into and used at a moments notice. 
We have designed and are implementing a nitrogen supply panel in hopes of alleviating the "tapping into" of the nitrogen supply. The sole 
source of nitrogen to the hall is the tank outside of the gas shed and every time that it is "tapped into" the overall integrity of the system
is weakened which in turn increases the potential for system failure. The majority of nitrogen use in the past has been purge and backfill 
operations and therefore not a critical concern. The RICH detector is the first and only detector in the hall to be critically dependent on 
nitrogen flow and requires all us to change our way of thinking when it comes to the importance of the supply. I would like to suggest that the 
very first thing we do is add administrative tags to the supply valves going to the hall that contain contact and notification information, 
instructing personnel to call prior to operating the valves. I also think that it is imperative to add an interlocked back up supply that will
take over in the case of a failure that can not be repaired in a very short period of time. In closing I am certain that with continued communication 
and a solid team effort we can make this a very worry free system.

Thank you
Denny Insley

         
----- Original Message -----
From: "Patrizia Rossi" <rossi at jlab.org>
To: "Amrit Yegneswaran" <yeg at jlab.org>
Cc: "Tyler Lemon" <tlemon at jlab.org>, "dsg-rich" <dsg-rich at jlab.org>, "Bob Miller" <rmiller at jlab.org>, "Marco Mirazita" <Marco.Mirazita at lnf.infn.it>, "Denny Insley" <dinsley at jlab.org>
Sent: Tuesday, September 18, 2018 2:26:18 PM
Subject: Re: [Dsg-rich] URGENT: RICH alarm

yes, I agree with Amrit.
Thank you Tyler for the excellent analysis!
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> On 18/set/2018, at 14:22, Amrit Yegneswaran <yeg at jlab.org> wrote:
> 
> thanks for the excellent analysis tyler.
> this helps us set a baseline and endorses the fact that prior to scheduled work, we have to take appropriate action.
> for instance, the rich detector must have emergency nitrogen in the hall to switch to prior to scheduled work.
> 
> detectors are like trust,
> takes years to build , seconds to destroy, and forever to repair.
> 
> 
> From: "Tyler Lemon" <tlemon at jlab.org>
> To: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>, "dsg-rich" <dsg-rich at jlab.org>
> Cc: "Robert Miller" <rmiller at jlab.org>, "Denny Insley" <dinsley at jlab.org>
> Sent: Tuesday, September 18, 2018 2:09:09 PM
> Subject: Re: [Dsg-rich] URGENT: RICH alarm
> 
> Hello,
> 
> In addition to the relative humidity sensors, we have the moisture transducer measuring the water concentration at the N2 Exhaust line.
> 
> When N2 flow stopped there was 41.77 ppm of H2O.
> When N2 flow restarted, water concentration had increased to 46.72 ppm (4.95 ppm, or 11.86% overall, increase).
> One hour later, water concentration dropped to 44.17 ppm (2.55 ppm, or 5.46% overall, decrease).
> 
> Attached is an updated table with the moisture transducer added in the last row in blue. Also attached is a plot during this time period for the moisture transducer.
> 
> Best regards,
> Tyler
> From: "Tyler Lemon" <tlemon at jlab.org>
> To: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>, "dsg-rich" <dsg-rich at jlab.org>
> Cc: "Robert Miller" <rmiller at jlab.org>, "Denny Insley" <dinsley at jlab.org>
> Sent: Tuesday, September 18, 2018 1:44:49 PM
> Subject: Re: [Dsg-rich] URGENT: RICH alarm
> 
> Hello,
> 
> From the attached plot and table, it looks like during the time with no N2 flow, humidity increased by 0.28% RH (~ 30% overall increase from before flow loss).
> 
> After flow had been restored for one hour, the humidity had decreased by 0.18% RH (~ 16% overall decrease from when flow was restored).
> 
> Best regards,
> Tyler
> 
> From: "Amrit Yegneswaran" <yeg at jlab.org>
> To: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>
> Cc: "dsg-rich" <dsg-rich at jlab.org>, "Robert Miller" <rmiller at jlab.org>, "Denny Insley" <dinsley at jlab.org>
> Sent: Tuesday, September 18, 2018 11:02:43 AM
> Subject: Re: [Dsg-rich] URGENT: RICH alarm
> 
> denny, bob 
> in future, for scheduled work please let the RICH group know before hand.
> amrit
> 
> From: "Marco Mirazita" <Marco.Mirazita at lnf.infn.it>
> To: "Robert Miller" <rmiller at jlab.org>
> Cc: "dsg-rich" <dsg-rich at jlab.org>, "Denny Insley" <dinsley at jlab.org>
> Sent: Tuesday, September 18, 2018 10:56:28 AM
> Subject: Re: [Dsg-rich] URGENT: RICH alarm
> 
> Hi all,
> it is back now.
> Marco
> 
> 
> Il 2018-09-18 16:54 Robert Miller ha scritto:
> > Hi Tyler,
> > 
> > The N2 was stopped to add a valve; it will be back within the next 10
> > minutes.
> > 
> > Bob
> > 
> > Sent from my iPhone
> > 
> > On Sep 18, 2018, at 10:51 AM, Tyler Lemon <tlemon at jlab.org> wrote:
> > 
> >> Hello Bob and Denny,
> >> 
> >> Is there any work being done on the forward carriage nitrogen supply
> >> line?
> >> 
> >> RICH lost N2 flow and the aerogel needs to stay constantly purged by
> >> N2 to stay dry.
> >> 
> >> Tyler
> >> 
> >> -------------------------
> >> 
> >> FROM: "Mirazita Marco" <Marco.Mirazita at lnf.infn.it>
> >> TO: rich at jlab.org, "dsg-rich" <dsg-rich at jlab.org>
> >> SENT: Tuesday, September 18, 2018 10:39:21 AM
> >> SUBJECT: [Dsg-rich] URGENT: RICH alarm
> >> 
> >> Hi all,
> >> it seems that few minutes ago the N2 flow dropped to 0.
> >> Can someone please check what is going on?
> >> Thank you
> >> Marco
> >> 
> >> _______________________________________________
> >> Dsg-rich mailing list
> >> Dsg-rich at jlab.org
> >> https://mailman.jlab.org/mailman/listinfo/dsg-rich [1]
> > 
> >> <n2flow.png>
> > 
> > 
> > Links:
> > ------
> > [1] https://mailman.jlab.org/mailman/listinfo/dsg-rich
> > 
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