October 22, 2008

Unpolarized Measurents:

A 2x4x8" aluminum brick was placed at the HRRL export in order to destroy the photon polarization. Rate measurements were made with the descriminator and HV settings used the past week. Then the constant fraction descriminator was replaced with a threshold descriminator on two detectors but not the reference detector.

ADC =0 => Reference Detector D

ADC = 1 => NaI

ADC=2 => Detector C

ADC = 3 => Detector A

0.1675

Matched HV and Threshold Descriminator

2 Runs were taken with the following settings

100 ms Threshold descrimnaotr

[math]HV_{Det A}[/math] =

[math]HV_{Det_C}[/math] =

Run 229

NaI spectrum monitoring the photon flux during run 229

Run 234

NaI spectrum monitoring the photon flux during run 234