[PIPE2D-902] Measure the flux of calibration lamps and compare explicitly with prediction from Jim & Erin Created: 20/Sep/21  Updated: 17/Aug/22  Resolved: 02/Oct/21

Status: Done
Project: DRP 2-D Pipeline
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Task Priority: Normal
Reporter: ncaplar Assignee: ncaplar
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Attachments: PNG File argon.png     PNG File comparison_rot0_and_ring.png     PNG File continuum and ring lamp simple spectrum.png     PDF File continuum_counts.pdf     File continuum_red.csv     PNG File dif_from_mean_rotator.png     PNG File ErinSnrspectra.png     PNG File fit_matched_to_total_sur_brig_prediction.png     File new_Ar_linemeas.csv     File new_HgCd_linemeas.csv     File new_Kr_linemeas.csv     File new_Ne_linemeas.csv     File new_Xe_linemeas.csv     PNG File rotation_0.png     PDF File Thoughts.pdf    
Issue Links:
Relates
relates to PIPE2D-1069 Process June 2022 PFI non-uniformity ... Done
relates to PIPE2D-911 Compare flux in observatiosn of sky w... Done
relates to PIPE2D-918 Provide flux data for calibration lam... Done
Story Points: 1
Sprint: 2DDRP-2021 A 10

 Description   

Based on work done in PIPE2D-893, compare quantitatively the predicted flux in the lamps (as predicted by Jim and Erin) and the flux seen in the data. 

 Addition to the ticket, based on requests from Jim on the telecon on September 20:

1. Do the same analysis as done for Ne, Ar, Kr and continuum for HgCd lamp.
2. Compare the flux with the ring lamps
3. Create rough estimate of the spectrum of the continuum lamp 

Relevant notebook is on Tiger, at:

/home/ncaplar/Pipeline_notebooks/PIPE2D-902 (Compare fluxes of lamps).ipynb


 Comments   
Comment by ncaplar [ 21/Sep/21 ]

I have compared the fluxes for Argon, Neon, Krypton and continuum lamps with the predictions (provided by Jim and Erin). Those predictions are attached to this ticket. The analysis has been only done in red.

I have looked at the fluxes for 3 brightest spots for Argon and Krypton, and 5 for Neon. I have also looked at 3 different position for continuum lamp. All of the analysis has been done on raw images, on the fiber at x=2545. This is one of the brighter fibers that I have see by visual inspections of the images.

Argon.png shows the predicted and measured flux for the spots. 3 measured spots are denoted by orange points, and the wavelength has been indicated by the gray line. For lines at 763.50532027, 811.5521071 , 912.32685895 nm, the measured ratio between the predicted and measured values is 20.71333146, 23.75641397, 18.92842034, for mean ratio of 21.

For Neon the ratio has been measured for spots at  640.22319559, 650.61847332, 667.85471749, 692.9226948 , 703.23178381 nm. The observed ratio is 9.85922264, 8.53241257, 4.13189759, 6.77602784, 4.98336609, for the mean ratio of 6.9.

For Krypton the ratio has been measured for spots at 760.13753536, 811.27260789, 877.66812554 nm. The observed ratio is 11.74454834, 16.88226871, 14.40388648, for the mean rati of 14.3.

For continuum the ratio has been measured at 697, 795 and 920 nm. The observed ratio is 55.6, 71.98, 73.34, for the mean ratio of 66.97.

This ratio is roughly 3 times higher than previously claimed 20, as Erin explain that the value provided in continuum_red.csv and shown in continuum_counts.pdf is ``this is integrated over the wavelength range of a single PFS pixel in the dispersion direction, then divided by 3.22 to try to account for the spread in the spatial direction''. As such these values, which are in the range of between 6000 to 8000 counts for large portions of red dectector as per one physical pixel, and not integrated over the spatial direction, as I assumed previously. 

 

 

 

 

 

Comment by ncaplar [ 22/Sep/21 ]

For HgCd the ratio has been measured for spots at 508.59404793, 435.80522598, 546.10778179, 576.99145691, 579.03170651 nm. The observed ratio is 10.72966319, 3.4212724 , 6.19183228, 5.02193196, 4.82289145, for the mean ratio of 6.

Comment by ncaplar [ 22/Sep/21 ]

The ring lamp is around 30 to 60 times brighter, depending on which part of the spectrum one is observing. See continuum and ring lamp simple spectrum.png. I also want to note that the nonuniform flux behavior between neighboring fibers, where flux is increasing from one side to the other within a block is very similar in the exposures taken with ring and/or continuum lamp. 

Comment by ncaplar [ 24/Sep/21 ]

Update September 23:Update September 23:
1. Figure rotation_0.png shows: Left panel: The flux in the exposure with rotator at 0. The scale is from max=128k counts to 64k counts, i.e., yellow are the brightest fibers and bluest fibers are at the half flux. The gray dots show the deduced center of the illumination (x=-10,y=-4), which has been deduced using data shown in the center panel. Center panel: the flux in the fibers as a function of the distance from the center. Center has been fitted in order to minimize the scatter around the 2nd degree fit. Right panel: The residual after fit to the distance from the center. I do not see any strong residual dependence.
2. dif_from_mean_rotator.png shows the difference from the mean value at each rotator position. ``Mean value'' has been constructed as an average of all 4 flux measurements. We can observe the rotation. The scale is from -6k to +6k. The max value in the images is as above, roughly from 128k to 64k.
3. comparison_rot0_and_ring.png shows: Left panel:  The flux in the exposure with rotator at 0. Same panel as in Figure rotation_0.png. Center panel: The flux in the exposure taken with ring lamp, prepared in the same way. The center, gray dot, is still the same center as in the left panel. By accident, the fluxes in both exposures are very similar. Right panel: The difference between two illuminations. 

Comment by ncaplar [ 02/Oct/21 ]

Further discussion with Jim and the whole group will continue. Comparison with the fluxes from the sky observation to be placed in a new ticket.

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