RE: coordinate system

Precisely. After talking with Glenn and Josh and looking at what KAMLAND and SNO did, I think a more
sensible choice might be:

z-axis -- plumb-line up, or zenith angle 0. Our liquid always measures this.

xy-plane is perpindicular to z.

x-axis (phi=0) -- draw a line from the midpoint of the two reactor cores to the center of the upstream near detector (if there are two, then to the one most likely to be fixed. Project the line to the xy-plane.

y = z X x.

This way the z-axis is the one about which the detector has rotational symmetry. The beam is mostly along the x axis with a small -z component and a y component that typically averages to zero. The x and y axes will also be approximate symmetry axes for the cavern and veto structures.

TB

Tim Bolton
Professor
High Energy Physics Group
Kansas State University
tbolton@ksu.edu
785-532-1664

-----Original Message-----
From: Jonathan Link [mailto:link@fnal.gov]
Sent: Tue 12/21/2004 10:52 PM
To: Bolton, Tim
Cc: reactor-vwg@mit.edu
Subject: Re: coordinate system
 
Which beam? Reactor one or reactor two?

Bolton, Tim wrote:

>I'm not sure we have even made a basic convention for the coordinate system.
>
>ReactorFsim tacitly assumes
>
>z = "beam direction", with z increasing as one moves away from reactor.
>
>y = "up"
>
>x = y X z
>
>And x and y don't really matter.
>
>But there are subtleties.
>
>-- Where is x=y=z=0? Center of one detector (which one). Midpoint between two reactor cores? Ed's office?
>
>-- Can we assume that all detectors are centered on the z-axis.
>
>-- y is not really "up" in this convention, because of "beam tilt". Should it be "up" as in vertical or "up as perpindicular to beam?
>
>Maybe there is a better choice. We should make it before we start introducing elements that define direction.
>
>TB
>
>
>
>
>Tim Bolton
>Professor
>High Energy Physics Group
>Kansas State University
>tbolton@ksu.edu
>785-532-1664
>
>
>
>-----Original Message-----
>From: ELog@CYCLOTRON.mit.edu [mailto:ELog@CYCLOTRON.mit.edu]
>Sent: Tue 12/21/2004 9:26 AM
>To: reactor-vwg@MIT.EDU
>Subject: New ELOG entry
>
>A new entry has been submitted on cyclo.mit.edu
>
>Logbook : Veto Working Group
>Author : Peter Fisher
>Type : Agenda
>Category : General
>Subject : Short phone meeting Tuesday, 3:30 pm, 617-324-7520
>
>Logbook URL : http://cyclo.mit.edu:8080/Veto+Working+Group/6
>
>=================================
>
>Please note the meeting will start a half hour later than usual.
>
>Agenda
>------
>
>1. Nomenclature and general veto configurations - 10'
> At the last meeting with discussed some general configurations for the
>veto simulation. I've made some simple sketches which are on the E-log.
>I'm happy to change any label to be consistant with history, but we should
>agree on what we call things.
>
>2. Simulation progress and plans - 15'
> Work has begun on flux functions for ReactorFsim and ther are
>opprotunities for people to contribute. We should briefly review what is
>being done.
>
>The next meeting will be Jan. 4, 2004.
>
>Peter
>
>
>
>
>
Received on Wed Dec 22 08:16:41 2004