Compton study from experimental data
Download
1 / 17

Compton Study from Experimental Data - PowerPoint PPT Presentation


  • 141 Views
  • Uploaded on

Compton Study from Experimental Data. Purpose:. To show that method for selecting single arm Compton events works on real Compton data and to see if we can qualitatively see single arm Compton events in production runs. Double-Arm (Tested on dedicated Compton run # 4658).

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Compton Study from Experimental Data ' - conner


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Purpose
Purpose:

  • To show that method for selecting single arm Compton events works on real Compton data and to see if we can qualitatively see single arm Compton events in production runs.

Kelli Hardy


Double arm tested on dedicated compton run 4658
Double-Arm (Tested on dedicated Compton run # 4658)

Procedure for selecting Compton events: Events in which:

  • 2 clusters in HyCal  

  • Timing  difference between trigger and tagger was less than 5ns (Timing cut) (see Figures 1&2)

  • Sum of the two clusters was greater than 0.5Gev (Energy cut)

  • (Radial cut): 4 cm< r< 34cm

Figure 1: Timing difference between tagger and trigger

Kelli Hardy


Double arm
Double-Arm

From analysis of timing coincidence plot , a timing window of 5ns was taken. (As result T-counter 9 was excluded)

Figure 2: Timing difference between tagger and trigger

Kelli Hardy


Double arm1
Double-Arm

Figure 3: Energy sum of two clusters minus reconstructed tagger energy

Kelli Hardy


Double arm2
Double-Arm

After taking elasticity and minimum cluster separation cuts, get Df peak at ~180 º.

Figure 4: Df distribution

Kelli Hardy


Double arm3
Double-Arm

Blue dots correspond to photons and red dot correspond to electrons.

Figure 5: Kinematic correlation between cluster

energy and cluster angle

Kelli Hardy


Double arm4
Double-Arm

After applying Compton kinematic cuts , a peak at ~1 is obtained indicating Compton events. This shows the method for selecting Compton events works for double-arm case.

Figure 6:  Pure Compton events after elasticity,

Df and minimum angular separation cuts

Kelli Hardy


Single arm compton
Single-arm Compton

Used same procedure for selecting double arm Compton events with exception of:

  • Select events with 1 cluster

  • Assume all events are Compton

Figure 7: Sign of single arm Compton events in production run

Kelli Hardy


Single arm compton1
Single-arm Compton

Figure 8: Energy Ratio from production run with r > 6cm

Kelli Hardy


Single arm compton2
Single-arm Compton

Background decreases with increasing radial cut, but Compton events are also cut out.

Figure 9: Energy Ratio from production run with r > 8cm

Kelli Hardy


Double arm compton in production data
Double-arm Compton in Production Data

Purpose: To search for double-arm Compton events produced off of the vacuum window of pair spectrometer magnet in production data.Procedure:Same procedure for selecting Compton events in dedicated Compton run was used, with the following exceptions: 

  • Pion invariant mass cut (Z measured from target)

  • Z measured from window

Kelli Hardy


Double arm compton in production data1
Double-arm Compton in Production Data

Figure 10: Elasticity plot with arrow indicating possible

double arm Compton events at ~ 0

Kelli Hardy


Double arm compton in production data2
Double-arm Compton in Production Data

Small peak ~0.135 Gev shows pion invariant mass.

where is the opening angle between the two photons.

Figure 11: Mgginvariant mass distribution

Kelli Hardy


Double arm compton in production data3
Double-arm Compton in Production Data

After cutting elasticity and pion invariant mass, a Df distribution with peak around 180º is seen.

Figure 12: Df distribution with peak~ 180º

Kelli Hardy


Double arm compton in production data4
Double-arm Compton in Production Data

Plot was made of cluster energy vs. cluster angle to look for possible indications of double arm Compton events. Two different colors correspond to the two different clusters.

Figure 13: Kinematic correlation between cluster

energy and cluster angle

Kelli Hardy


Summary
Summary

  • Qualitatively, plot for single-arm Compton agrees with plots shown earlier.

  • We have good chance to isolate single-arm Compton events, however work is needed to understand how this process can be used for the following two purposes:

  •  To use this process to monitor Hycal gain

  •  To monitor efficiency of whole experimental setup

  • There seems to be indication of Compton double-arm events produced off of the pair spectrometer vacuum window.

Kelli Hardy


ad