Below each description is a link to a kumac that will draw the
object as shown; the colors may be different depending on how
they are defined in your euclid file.
This is the euclid file needed for all of the kumacs below to
function properly. Some of the colors and definitions are a
little different from the standard ones in order to make the
pictures.
Euclid file
Draw the global volume
WARNING!
This page is meant as an introduction to the GEANT3 geometry defined in the .euclid files for the
Qweak experiment. It is not intended as the database for the experiment's geometry, but rather as
a description of the simulation geometry, which is greatly simplified. The main parts of the
experiment that are included in the simulation are the following:
Target and Target Chamber Attachments
Collimator System and Collimator Stands and Walls
Minitorus
Main Torus
Beamline
Focal Plane Detectors
A description of the geometry for each object will be in the column on the left, and a picture of
the component will be in the column on the right. Unless otherwise stated, the orientation for
all of the pictures is x is up, y is to the right and z points up and to the right (downstream).
This page may not be updated as often as the actual geometry is.
Clicking on a picture will open a larger version of it.
Target and Target Chamber Attachments
The target mother volume is helium and is 35.00889 cm long and
1" in radius.
The target is composed of a cylinder 35.00889 cm long and 1" in
radius. The target cell is made of aluminum with 3.5 mil
endwindows and a 20 mil tube around the hydrogen. That makes
the volume that is actually hydrogen 35 cm long and 2.4892 cm
in radius. The target is centered on the beam axis, 650 cm
upstream of the center of the main magnet.
There is an aluminum vacuum exit window defined as 10 mils thick
and inner diameter 2.4892 cm, outer diameter 20 cm, located
5.0327 cm downstream of the downstream end of the target.
Target Attachments
The mother volume of the target chamber attachments is helium,
with upstream, middle and downstream parts. There are aluminum
gasket-like volumes in the upstream and middle parts, with a
lead one in the middle part as well.
The target chamber attachments are defined in a manner similar
to the collimators. Inner and outer cones define the theta
acceptance and tubs define the phi acceptance. The cones and
tubs are made of aluminum.
Draw the target
Draw the vacuum window
Draw the target chamber attachments
Collimator and Collimator Stand and Walls
There are three collimators. The furthest upstream collimator
is defined as collimator 1. The middle collimator is the
primary or acceptance defining collimator. The furthest
downstream collimator is defined as collimator 3.
The collimator mother volumes are all defined as helium. The
precision parts of the collimators are defined as lead. All
3 consist of inner and outer cones and 8 tubs. The cones
define the theta acceptance and the tubs define the phi
acceptance.
The first collimator is contained in a box made of concrete and
has helium tubes of varying thicknesses in z which are made of
helium. In addition there is a gasket-like volume made of
aluminum. The phi angles of the opening are +/- 12 degrees,
and the theta angles of the opening are larger than the
primary collimator. There are two additional gasket-like
objects made of aluminum at the upstream and downstream faces.
The first collimator is 10.16 cm thick, centered at -553.33 cm
from the center of the main torus.
The primary collimator is simply the lead of the cones and tubs.
It has an upstream half (the primary) and a downstream half
(the third collimator). The primary collimator has a phi
acceptance of +/- 11 degrees and a theta acceptance of 6.38 and
14.51 degrees. The third collimator has a phi acceptance of
+/- 12 degrees and a theta acceptance of 5.47 and 14.56 degrees.
The primary collimator is 7.62 cm thick, centered at -338.91 cm
from the center of the main torus and the third collimator is
7.62 cm thick, centered at -259.24 cm from the main torus.
Collimator Stands and Walls
The collimator stands and walls are defined in the global
volume. They are made of concrete and are centered at
-427.46 cm from the main magnet. There are a "ceiling" and
a "floor" each 25.4 cm thick and 120 cm by 147.45 cm and a
"base" with dimensions 112.7x120x147.5cm^3.
Draw the first collimator.
Draw the primary collimator.
Draw the collimator stand and walls.
Minitorus
The minitorus mother volume is helium.
The minitorus consists of 8 circular coils evenly placed around
the beamline. The coils are 2.8 cm thick and have in inner
radius of 8.75 cm and an outer radius of 26.25 cm. The outer
radius is 5 cm from the center of the beamline. The minitorus
is centered at -505 cm from the center of the main torus.
Draw the mini torus.
Main Torus
The main torus mother volume is helium.
The main torus consists of 8 coils evenly placed around the
beamline. The coils are 8 cm thick and have in inner radius of
25 cm and an outer radius of 75 cm. The straight part of the
coils is 220 cm long. The outer radius is 15 cm from the center
of the beamline. The main torus is centered on the beamline and
is located at z=0 in the mother volume.
Draw the main torus.
Beamline
General:
The beamline mother volume is helium and is 700 cm long and
50 cm in radius, centered in the center of the global volume.
The inner beampipe radius increases in radius incrementally
going downstream, and the amount of sheilding decreases.
Whenever a change in inner radius occurs, there is a gasket-
like object defined. The beamline is made of aluminum, and
the sheilding is lead. The "gaskets" are either aluminum or
lead.
Specific:
The following is subject to change as the minitorus and
primary collimator optimization continues.
The smallest inner diameter of the beamline is 5.08 cm. The
beamline thickness is .635 cm. The beamline begins 53.77 cm
downstream of the downstream end of the target. The beamline
sheilding begins some distance after that. The radius of the
beamline increases in steps to 8.255 cm at the location of the
main magnet, with an outer sheilding radius of 13.335 cm. The
largest beamline radius, furthest downstream, is 13.335 with
an outer sheilding radius of 18.416 cm.
Draw the beamline
Focal Plane Detectors
The detectors are defined as vacuum and are .25 cm thick. They
are located throughout the global volume and vary in inner and
outer diameter depending on their z location. These detectors
will vary in location, size and shape depending on the groups'
individual needs.
Our detectors are placed before and after the minitorus, before
and after the primary collimator, at the front face of each of
the Region II chambers and before and after the main magnet.
The rest of our detectors are placed near the focal plane,
10 cm apart, in order to find the best z location for the
cerenkov bars.
Draw the focal plane detectors.
