Qweak Installation

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Information for installing the R1 chambers into Hall C

Installation Dates

Date Milestone
Planned (11/08) Completed
11/25/09 Qweak Install begins with Qtor
3/18/10 Install Rotator
3/31/10 install Region 1 Chamber
4/21/10 Survey Region 1 Chamber
7/22/10 Qweak Commission
11/23/10 Qweak Run 1
4/11/11 Qweak Run 2


Survey tolorance
The accuracy in the absolute location of an object
Alignment Tolerance
The accuracy of an object relative some other known object.
"Would like to"
desired alignment accuracy
"Must have"
Required alignment accuracy
"Known to"
desired survey accuracy


The charge collector strips are less than 0.4 mm wide. The concentric strips can give you a direct measurement of the electron scattering angle [math]\theta[/math] if they are properly alignment with the beam line.

The numbers below are just a Guess with no justification from a simulation or hand calculation.

Tolorance for GEM relative to the PRIMARY COLLIMATOR (2nd collimator)

Survey can pretend to do 50 micron resolution 200 micron resolution is no problem.

Survey marker tooling balls need 1/4 inch rods to mount prisms on. Should have at least 3, 1/4 holes on detector.

Coordinate "Would like to" "Must have" Known to
(mm) (mm) (mm)
X 0.05 0.2 0.2
Y 0.05 0.2 0.2
Z 1 10 1
Yaw(about Y)
Pitch (about X)
Roll(about Z) [math]\infty[/math] [math]\infty[/math] [math]\infty[/math]

Survey marker locations

ChargeColecotr coordinates.png

The coordinates given below are with respect to an arbitrary reference point identified by the cross hairs just below the label "B".

Point Design (x, y)(mm) Hall-C (x', y') (mm)
A 5.025; 60 7; 0
B 16.4858; 26.485 18.45658; -33.515
C 88.497; 3.492 90.477; -56.508
D 246.999; -18 248.979; -78
E 295.005; 60 296.985; 0
F 246.991; 138 248.971; 78
G 88.500; 116.493 90.48; 56.493
H 16.493; 93.488 18.473; 33.488

Chamber Gases

Region II and III wil use gas mixture:

% Volume Gas
88 Argon
10 CO2
2 Methane


JLAB supplies

4 SHV cables from GEM Rotator to Counting House
2 RJ45 cables freom rotator to GEM gumsticks located in dog house front of target
4 BNC Coax cables from GEM detector to Alena's scintillator coincidence NIM modules located near quartz detector
4 120 Volt power lines to dog house
2 120 Volt power lines to GEM rotator
cable from G0 32 MHz clock to V1495 in the dog house
coax cable from Alena's coincidence NIM modules to V1495 doghouse location

LaTech supplies

4 ribbon cables from V1495 in Doghouse to breakout box on rotator
2 RJ45 I2C cables from dog house upstream of target to breakout box on GEM rotator
6 (+2.5V) power lines from dog house to GEM rotator

Meeting Notes


1.  Briefly review the current status of your system:   is it  
a) assembled  

detector and rotator are assembled

b)  tested  

HV tested the detector. Rotator is tested and working

c) ready for shipping ?   Not ready for shipping.
If not, what are the remaining critical milestones and how will your group meet them?

Not ready for shipping. Remaining critical milestones are

i.)readout tests: The detector system (ionization chamber + DAQ readout) needs to be tested before installation into Hall C. The first test will use an electron beam at Idaho State University. The tests are on the schedule for the week of March 16. I believe this will slip by 1 month because of 3 problems which have occured with the accelerator. 6 VFAT readout cards are expected to be sent out the week of March 2, 2009.

ii.) Detector mounting system and signal cable holders: LaTech should provide input on this.

iii.) Slow Control GUI: LaTech Should provide input on this.

2.  Briefly summarize the installation and integration issues when your system is 
installed at JLab.    How will these be addressed?

i.) survey: the Detector has survey markers on the most downstream part which are visible outside the detector. Survey should be scheduled to prevent line of sight obstacles (ie, the 2nd collimator).

3.  Describe the tests to be made with beam during the commissioning phase for your system.   
What analysis tasks will need to be done to confirm that it is ready for production mode?

a.) is the detector working test. You should see pulses on the trigger output signal. A BNC cable should be run from alenas electronics to the counting house.

b.) timing tests, Is the readout in sync with the JLAB RF

c.)Point target tracking test, does R1 and R2 reconstruct straight line tracks to the location of a solid target?

4.  Briefly summarize the nature of the analysis software needed for your system and its 
current status.   Who is in charge of this software for your group?

a.) Tracking software for a Q^2 straight track measurement.

5.  Who is in charge of documentation (both hardware and software) for your system?  
How will general shift workers be trained to operate it?

a.) Documentation is needed to describe the Rotator control software (Klaus?), HV settings(?), and the VFAT setup procedure(Tony).

b.) a Tracking group member will be available during scheduled tracking shifts to operate the detectors and take data.

6.  List the members of the team dedicated to installing, commissioning and running your 
system for Qweak.   Indicate a schedule for who you plan to have at JLab and when.

My last version of the schedule has the following dates

3/18/10 Install rotator: K. Grimm

3/31/10 Install R1 Chamber: T. Forest: I am guessing that this means hook up power and the DAQ, I can put my name down.

4/21/10 Survey R1 chamber: Any want to sign up?

7/22/10: Qweak Commission: S. Wells + T. Forest?

7.  Does your system require a dedicated expert on each shift?   
Do you need to recruit additional manpower from the collaboration at large?

Yes, see answer to #5 above.

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