# DOCUMENTATION FOR ELECTICAL SAFETY REVIEW OF MINOS DETECTOR SYSTEM AT THE MINOS NEAR DETECTOR HALL

[Date Prepared]{.underline}: April 13, 2004

[Contact]{.underline}: Peter Shanahan

shanahan@fnal.gov

X8378

LDP: 630-218-3907

[Location]{.underline}: MINOS Near Detector Hall (Underground)

[Equipment]{.underline}: The MINOS Near Detector front-end, clock, high
voltage, readout and data-acquisition system. This includes 4 racks of
commercial equipment, and 35 racks of VME and NIM electronics designed
by the MINOS project.

[DOCUMENTATION FOR ELECTICAL SAFETY REVIEW OF MINOS DETECTOR SYSTEM AT
THE MINOS NEAR DETECTOR HALL
1](#documentation-for-electical-safety-review-of-minos-detector-system-at-the-minos-near-detector-hall)

[OVERVIEW 4](#__RefHeading___Toc69993923)

[Floor plan 5](#__RefHeading___Toc69993924)

[Racks 5](#__RefHeading___Toc69993925)

[Racks 6](#__RefHeading___Toc69993926)

[SAFETY SYSTEMS AND PROCEDURES 7](#__RefHeading___Toc69993927)

[Fusing 7](#__RefHeading___Toc69993928)

[Power Supply Procedures 7](#__RefHeading___Toc69993929)

[Rack Turn On Procedure. 7](#__RefHeading___Toc69993930)

[Power Supply Covers 7](#__RefHeading___Toc69993931)

[Rack Protection System and Rack AC Power Distribution
7](#__RefHeading___Toc69993932)

[RPS SYSTEM LOGIC / AC POWER DISTRIBUTION SKETCH
9](#__RefHeading___Toc69993933)

[RPS DC LINE SKETCH 9](#__RefHeading___Toc69993936)

[RPS DC LINE SKETCH 10](#__RefHeading___Toc69993937)

[MINDER (FRONT END) SYSTEM 16](#__RefHeading___Toc69993938)

[Rack overview 17](#__RefHeading___Toc69993939)

[Crate and Components 19](#__RefHeading___Toc69993953)

[MASTER (READOUT) SYSTEM 21](#__RefHeading___Toc69993954)

[Rack overview 22](#__RefHeading___Toc69993955)

[Crate and Components 24](#__RefHeading___Toc69993969)

[TIMING SYSTEM 26](#__RefHeading___Toc69993970)

[Rack Overview 27](#__RefHeading___Toc69993971)

[NIM Crate and Components 29](#__RefHeading___Toc69993981)

[VME Crate and Components 30](#__RefHeading___Toc69993984)

[DC POWER DISTRIBUTION 32](#__RefHeading___Toc69993985)

[OVERVIEW 33](#__RefHeading___Toc69993986)

[POWER HARNESSES 34](#__RefHeading___Toc69993987)

[SYSTEM INTERCONNECTS 40](#__RefHeading___Toc69993988)

[APPENDIX A 45](#__RefHeading___Toc69993989)

[SAFETY PROCEDURE DOCUMENTS 45](#__RefHeading___Toc69993990)

[APPENDIX B 48](#__RefHeading___Toc69993991)

[RPS CONTROLLER SCHEMATICS AND POWER MODIFICATIONS
48](#__RefHeading___Toc69993992)

[APPENDIX C 51](#__RefHeading___Toc69993993)

[Internal Safety and Quality Control Reviews
51](#__RefHeading___Toc69993994)

[APPENDIX D 58](#__RefHeading___Toc69993995)

[CABLE Safety 58](#cable-safety)

Comments and summary from the Jan. 8, 2002 MINOS internal safety and
quality control review for the PMT boxes ("Alner Boxes") follow.

\-\-\-\-\-\-\-- Original Message \-\-\-\-\-\-\--

Subject: Advisory Review of MINOS Alner Box

Date: Tue, 08 Jan 2002 14:54:18 -0600

From: David Boehnlein \<dave_b@fnal.gov\>

Reply-To: dave_b@fnal.gov

Organization: Fermilab

To: Jonathon Thron \<thron@anl.gov\>, drake@hep.anl.gov, Doug Michael

\<michael@cithe205.cithep.caltech.edu\>

CC: David Boehnlein \<dave_b@fnal.gov\>, John Elias \<elias@fnal.gov\>,

huffman@fnal.gov, Cat James \<cjames@fnal.gov\>, Keith Schuh

\<schuh@fnal.gov\>, shanahan@fnal.gov

ADVISORY REVIEW SUMMARY

MINOS NEAR DETECTOR PMT BOX

January 8, 2002

Several members of the Fermilab PPD MINOS safety review committee

examined a prototype of the near detector PMT (Alner) box, provided by

Gary Drake, for the purpose of providing advice and comments before the

actual boxes go into production. Committee members present were J.

Elias, D. Huffman, J. Priest, and K. Schuh. MINOS collaborators on hand

were D. Boehnlein, C. James and P. Shanahan. No serious safety concerns

were found. There were some comments and questions:

1\) Why is the double-connector layout used inside the box? While not a

safety concern, it seems that this design is more expensive than it
needs

to be. Why not soldered connections, at least for one side? - J. Elias

2\) The composition of the gasket, the ribbon cable and connectors
inside

the box should be halogen-free, if this is feasible. While the PMT box

itself does not present a fire hazard, if something else in the same
rack

should burn and heat up the box, off-gassing halogens from the
smoldering

cable might present a corrosion threat to otherwise undamaged

electronics. - J. Priest.

3\) The output to the QIE cannot be grounded, since the QIE electronics

require a floating anode. Hence, if the cable is unplugged. the pins

will assume the dynode potential. This is not seen as a safety hazard,

but if the cable is reconnected (without turning off the high voltage)

there is a possibility of damage to the QIE electronics. How is this

addressed? - J. Elias.

4\) Disassembling and re-assembling the box is made very difficult by
the

small holes in the connector plate and flanges. Each one is just wide

enough to accomodate the threaded rod. The cumulative tolerance for

putting 22 threaded rods through 22 such holes simultaneously is

frustratingly small. Seriously consider widening the holes. The washers

and gaskets should still provide adequate protection against light
leaks.

\- D. Boehnlein

From drake@anl.gov Mon Apr 19 12:00:58 2004

Date: Wed, 09 Jan 2002 08:19:40 -0600 (CST)

From: Gary Drake \<drake@anl.gov\>

To: David Boehnlein \<dave_b@fnal.gov\>

Cc: Jonathon Thron \<thron@anl.gov\>, drake@hep.anl.gov,

Doug Michael \<michael@cithe205.cithep.caltech.edu\>,

John Elias \<elias@fnal.gov\>, huffman@fnal.gov, Cat James
\<cjames@fnal.gov\>,

Keith Schuh \<schuh@fnal.gov\>, shanahan@fnal.gov

Subject: Re: Advisory Review of MINOS Alner Box

Dave & Co.,

I reply to John\'s question:

\> 3)  The output to the QIE cannot be grounded, since the QIE
electronics

\> require a floating anode.  Hence, if the cable is unplugged. the pins

\> will assume the dynode potential.  This is not seen as a safety
hazard,

\> but if the cable is reconnected (without turning off the high
voltage)

\> there is a possibility of damage to the QIE electronics.  How is this

\> addressed? - J. Elias.

I believe the question concerns the fact that the QIE cannot operate
with

a bleeder resistor. This is sometimes put between the anode and HV
ground

in the base to keep the anode from charging up when the cable is

unattached, and is often \~100K ohms in size. In CDF, we addressed

this by instead using a Zener diode circuit between the anode and
ground.

A typical protection circuit consists of a series Zener-signal diode

combination, although there are other variations. The Zener turns on
when

the anode potential becomes \~10V, depending on the type of Zener used.

The best place for this protection circuit is in the base. For

single-anode PMTs, this is relatively straight-forward. In the case of

the M64, there is very little room on the base for 64 protection
circuits,

which would require 128 more components. Again drawing from CDF

experience where we instrumented M16 tubes, the diode protection
circuits

were put on the VME transition cards, on the receiving end of the signal

cable. This scenario works as long as the signal cable is not unattached

from the transition board while the PMT has high voltage applied. We

intend to to the same thing here. We will post warning signs on the back

of the crate, warning people not to uplug the signal cables while high

voltage is on. There is no active circuitry in the back of the VME crate

that houses the QIEs, so the need to disconnect the signal cables should

be minimal.

Gary

...

Comments and summary from the Apr 7, 2004 MINOS internal safety and
quality control review for the Byra RPS controller power modification
follow.

From dave_b@fnal.gov Sun Apr 18 16:48:18 2004

Date: Wed, 07 Apr 2004 13:55:16 -0500

From: David Boehnlein \<dave_b@fnal.gov\>

To: Debbie Harris \<dharris@fnal.gov\>

Cc: rameika@fnal.gov, Gary Drake \<drake@anl.gov\>, Keith Schuh
\<schuh@fnal.gov\>,

Dave Huffman \<huffman@fnal.gov\>, Peter Shanahan \<shanahan@fnal.gov\>,

luebke@fnal.gov, Alec T. Habig \<habig@neutrino.d.umn.edu\>,
bbock@fnal.gov,

Curt Lerol \<lerol001@umn.edu\>

Subject: Safety Review of RPS Modifications

This note summarizes a safety review of modifications to the MINOS Rack

Protection System (RPS). The Bi-Ra RPS units are located in MINOS

electronics racks at both the near and far detectors. The units were

built with internal power supplies that have been found to generate RF

noise that can be picked up by MINOS electronics. The proposed remedy

for this is to connect the unit to an external power supply and bypass

the internal ones, as described in a technical note titled Modification

of the BiRa RPS Units for the MINOS Experiment, by Gary Drake. As a

modification to a commercial unit, this warranted a review. Gary showed

a modified unit to members of the MINOS safety review committee. There

were no comments or concerns from the committee or from the MINOS

collaborators in attendance. The units will be modified as proposed.

MINOS Safety Committee members in attendance: Paul Czarapata, Dave

Huffman, Keith Schuh

MINOS Collaborators in attendance: Brian Bock, Dave Boehnlein, Gary

Drake, Alec Habig, Bill Luebke, Peter Shanahan.

Notes prepared by Dave Boehnlein

Comments and summary from the Mar. 12, 2004 MINOS internal safety and
quality control review for the PIN Diode Auxiliary cards follow.

From dave_b@fnal.gov Sun Apr 18 16:47:43 2004

Date: Fri, 12 Mar 2004 14:11:00 -0600

From: David Boehnlein \<dave_b@fnal.gov\>

To: Debbie Harris \<dharris@fnal.gov\>

Cc: David Boehnlein \<dave_b@fnal.gov\>, Bob DeMaat \<demaat@fnal.gov\>,

nelson@fnal.gov, orr \<orr@fnal.gov\>, Peter Shanahan
\<shanahan@fnal.gov\>

Subject: MINOS Pin Diode Aux Card Review

MINOS ES&H/QA Review Summary

PIN Diode Aux Cards

A MINOS internal ES&H/QA review was held for the near detector PIN

diode aux cards, eight of which will be located in a crate in one

of the near detector master racks. The review committee included

Dave Boehnlein, Bob Demaat, Stan Orr, and Peter Shanahan. The

committee examined drawings and a sample card presented by Charles

Nelson. The card was found to be of good design and construction.

Charles Nelson keeps a binder with detailed documentation of the

card. Fusing appears adequate and there were no safety or QA

concerns expressed. Peter Shanahan reported that tests of the card

at Argonne have been satisfactory. The committee agreed that PIN

diode aux card has passed the internal review.

DJB

Comments and summary from the Nov. 4, 2002 MINOS internal safety and
quality control review for Printed Circuit Boards follow in the attached
document.

Comments and summary from the MINOS internal safety and quality control
and review for the LED Light Injection Pulser boxes follow.

Comments and summary from the MINOS internal safety and quality control
review for the MINDER Crate J2 backplane follow.

### 

### CABLE Safety

The following table shows the cables listed in the MINOS Near Detector
electronics system.

Comments and summaries of safety reviews by the ES&H cable experts
follow.