Difference between revisions of "Qweak Delta"

From New IAC Wiki
Jump to navigation Jump to search
Line 31: Line 31:
  
  
<math>\frac{{\mbox{QTOR(8921)}}{{\mbox{QTOR(7583)}} = \frac{650}{84} = 7.74</math>
+
<math>\frac{\mbox{QTOR(8921)}}{\mbox{QTOR(7583)}} = \frac{650}{84} = 7.74</math>
  
 
{| border="1"  |cellpadding="20" cellspacing="0  
 
{| border="1"  |cellpadding="20" cellspacing="0  

Revision as of 17:48, 19 February 2011

Expected results

D Delta Qweak Error.pngD Delta Qweak Error V1.png

The above Figure in EPS format :File:D Delta Qweak Error.eps

File:A d-delta-vs-Q2.xmgrace.txt


Atot d Delta Qweak Error.pngAtot d Delta Qweak Error V1.pngAtot d Delta Qweak Error V2.png

The above Figure in EPS format :File:Atot d Delta Qweak Error.eps

File:Atot d-delta-vs-Q2.xmgrace.txt


Media:LOI-03-105.pdf

Media:PCS_Report_4_LOI-03-105.pdf

Katherine's Table


Qweak Inelastic ElasticRates-vs-QTOR simulated.png

Ratio of Elastic to Inelastic Region Rates = [math]\frac{650 MHz}{20 MHz + 50 MHz}[/math] = 9.3:1 = Rate ratio for QTOR=100% / 75%

In the denominator 20 MHz = Inelastic rate and 50 MHz is the elastic rate; according to the simulation


Measured Elastic: Inelastic region ratio

[math]\frac{\mbox{QTOR(8921)}}{\mbox{QTOR(7583)}} = \frac{650}{84} = 7.74[/math]

Qtor Rate (MHz)
9367 590
9144 633
8921 650
8698 528
8475 278
8252 163
8109 131
8029 121
7806 97
7583 84
7360 78
7226 76
7137 74
7048 74
6958 72
6869 69
6780 67
6691 64
6468 58
6245 52


Using the root command below

Mps_Tree->Draw("2*qwk_md3pos.hw_sum_raw/(qwk_bcm1.hw_sum+qwk_bcm2.hw_sum)","ErrorFlag==0")


I saw

Yield of MD3 Pos in Run 9905 = 1.644E4 MD counts/BPM counts

Yield of MD3 Pos in Run 9912 = 1.143E5 MD counts/BPM counts

Giving a ratio of 6.95


If I add both bar ends

Mps_Tree->Draw("2*(qwk_md3pos.hw_sum_raw+qwk_md3neg.hw_sum_raw)/(qwk_bcm1.hw_sum+qwk_bcm2.hw_sum)","ErrorFlag==0")

I saw

Yield of MD3 Pos in Run 9905 = 4.179E4 MD counts/BPM counts

Yield of MD3 Pos in Run 9912 = 3.239E5 MD counts/BPM counts

Giving a ratio of 7.75


using

Mps_Tree->Draw("qwk_mdallbars.hw_sum","ErrorFlag==0")


Yield of MD3 Pos in Run 9905 = 0.027 MD counts/BPM counts

Yield of MD3 Pos in Run 9912 = 0.0030 MD counts/BPM counts

ratio = 8.9


There seems to be some error in the comparison.

using the Hel tree

Hel_Tree->Draw("yield_qwk_mdallbars.hw_sum","ErrorFlag==0")

Shows same results as MPS tree mdallbars tree

Elastic Aluminum Asymetry

The Aluminum asymmetry was measured to be [math]1.61 \pm 0.16[/math] PPM

0.2 MHz/nA using warm gas target

Warm gas contribution about same size as downstream aluminum window.

To do aluminum measurement we can't use warm gas cell.


Aluminum window dilution 0.022+/- 0.002

Transverse Aluminum in Elastic

A sin wave with amplitude of about 4 PPM

You can weight the yields so the transverse asymmetry gets averaged over all octants.


File:Shi-Lin Zhu hep-ph-0107076 2001.pdf

first Inelastic Data

Asym -vs- QTOR

From Logbook entry https://qweak.jlab.org/elog/Analysis+%26+Simulation/254

200

The inelastic region of interest is expected to line up o the quartz bars when QTOR ~ 0.85 of its value for elastics.

In Feb 2011, QTOR(elastic) = 8921.

=> QTOR(Delta) = 0.85 \times 8921 = 7582

Run 9908

1 hour run with HWP OUT

https://hallcweb.jlab.org/hclog/1102_archive/110211010249.html https://hallcweb.jlab.org/hclog/1102_archive/110211020513.html

Run 9905

1 hour run with HWP IN

https://hallcweb.jlab.org/hclog/1102_archive/110210233842.html https://hallcweb.jlab.org/hclog/1102_archive/110211002416.html

Combining 2 hour of data taking

QTOR= 6700 Amps

I_{beam} = 145 \mu A


[math]A_{raw} = 1.296 \pm 0.579[/math]= Asymmetry averaged over all Main Detectors


If I assume only having 50 \mu A then I would need to take 6 hours of data to get the same statistic as above.

If I take a week of data at 50 \muA then that would correspond to 28 runs like the above.

So the uncertainty would be reduced by [math]\sqrt{28} = 5.29[/math] The measurement would have an uncertainty of 0.579/sqrt{28} = 0.1 PPM

background

Dave Mack's technical note on Qweak Background contributions and propogating their error. File:Qweak Doc 965 v1.pdf

Regression

https://qweak.jlab.org/wiki/index.php/Q-weak_Regression_Wiki_Page

Data Analysis

getting Qweak data from the Silo

jcache -g hallc /mss/hallc/qweak/rootfiles/pass0/*run number here*

looking for GOOD runs in database

There is a GUI interface on cdaql4 which can be run to look at run numbers and see their quality as recorded in the data base.


On cdaql4 run

./good_for_GUI

Root file format

The Qweak root files contain 2 trees ( MPS_Tree and EL_Tree). As the names suggest, the MPS tree contains data from devices for each Helicity bin. The HLS tree constructs helicity differences and asymmetries for each device in the data stream.

The devices listed in each tree above are folders which have sorted the data into 4 time windows within the helicity gate.

In the MPS_Tree there is a Bock0, Block1, Block2, Block3.

Drawing tree elements

Mps_Tree->Draw("qwk_bcm1.hw_sum","ErrorFlag==0")

If you get an error try

.ls

or try going up to the file subdirectory

if you pass the filename on the command line then the file is opened under the name file(0) so

_file0->cd()

should take you to the main subdirectory.


I think using the old TBrowser(0 screws up the pointers. "cd" to the file pointer when that happens.