Revision as of 19:03, 18 October 2022

09/19/22

Investigated non-linearity of peak sensing ADC due to issues arising in energy calibrations and efficiency measurements.

Modified existing calibration code to use non-linear regression to account for ADC.

Calculated ADC dead time for live-time correction to efficiency measurement count rates and calculated dead time per experiment.

Designed holder for Gd foils needed for CaGaS Phase II experiment. To be 3D printed and tested for tolerances.

Printed both parts of the Gd foil holder for CaGaS Phase II.
- Parts fit together adequately considering they're 3D printed and not machined.
- M3 bolts threaded through first part of the holder.
- M3 nuts pressed into the second part of the holder.
- Parts printed out of PETG plastic with low density infill (10%).

Edited rebinning code for energy calibrations for data sets collected with ADC to account for changes in calibration code.
- Energy calibration script now uses 2nd order polynomial regression to account for nonlinearity of ADC
- The coefficients from the regression are passed to another script to rebin ADC data from channel to energy, preserving bin count, but bin width will increase as a function of energy.
  - End goal is to pass coefficients into rebinning function and draw energy calibrated plot in the same script.

Designed Gd₂O₃ powder holder for CaGaS Phase II.
- Have spray on clear coat to seal plastic after printing is complete in hopes that powder will not stick between printed layers when used.

Documented Gd holders in wiki with rendered images and a description of intended use.

Continued to research live time correction for HPGe count rates and think I have applied the correction correctly at the initial measurement level, which will be propagated through to efficiency calculations.

Researched and tested different integration methods for more accurate measurement of counts in energy peak to compare to Gaussian fit.

Created tentative list of committee members with major advisor for PhD proposal defense and future dissertation defense.

Began the 3D print of Gd₂O₃ holder for CaGaS Phase II.
- Both parts printed and fit together tightly. Need to be sealed for use with powder.
- Updated wiki documentation with images of the holders.

Working with ISU Environmental Health & Safety to set up time to treat and coat lead bricks to build CaGaS Phase II setup.
- Air monitoring and respirators are required per ISU EH&S safety protocols.

Designed and printed a holder for Cs137 calibration source for storage in lab (signed off with RSO) for easy point calibrations using HPGe.

Researched dead time adjustment in Practical Gamma-ray Spectrometry by Gordon Gilmore
- Collected 50 data points for ADC gate width, read out controller trigger width, and the delay between end of gate and beginning of read trigger.
- Found dead time per pulse which includes memory storage time, thanks to reading the aforementioned book.

Worked to re-plot and integrate Eu152 peaks, but source data file seems to be corrupted. Will collect new set of data on Monday (10/10/22) when I can access calibration sources.
- Re-plotting is necessary for new integration with 2nd order polynomial binning and new live time correction.
- Collecting a new Eu152 spectrum is needed before CaGaS Phase II for new energy calibration as NIM bin has been power cycled and spec-amp gain has shifted.

Moved extra lead for CaGaS Phase II from lead storage at ISU to lab for coating prior to use.

Fixed energy calibration code thanks to input from a colleague.
- Machine precision and how ROOT interprets bins was cause of the issue.

Designed tools to use to level and compact powder into the powder holder for use during CaGaS Phase II.
- Designed new covers for powder holder to better accommodate for different thicknesses of powder.

Experimentally confirmed minimum dead and maximum bounds on dead time of data acquisition system per event after questions from colleague and plotted voltage traces for documentation.

Refit ¹⁵²Eu energy peaks with gaussians + linear background and recalculated efficiencies using live time correction.
- Finished replotting and calculating uncertainty in HPGe efficiency measurements to present next week, all calibration sources (¹⁵²Eu, ¹³⁷Cs, & ⁶⁰Co).

Met with collaborators and discussed FY23 work scope.
- Setup recurring meetings biweekly starting 10/19/22.

Wrote up efficiency measurement results, explained in detail how the calculations work.
- Wrote up and defined equations for uncertainty calculations, found lack of count statistics is highly influencing uncertainty in efficiency measurements. Working to rectify by collecting new data sets with ¹⁵²Eu with increased run time.

@@ Line 83: / Line 83: @@
 * Wrote up efficiency measurement results, explained in detail how the calculations work.
+** Wrote up and defined equations for uncertainty calculations, found lack of count statistics is highly influencing uncertainty in efficiency measurements. Working to rectify by collecting new data sets with <sup>152</sup>Eu with increased run time.
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