Test for PMT afterpulse with He Gas Flowing Result of SN2126 2. SN1439 under test 3. Plan Heejong Kim 2018-12-02

Afterpulse rate change of SN2126 with He Gas blowing Stop He Start He http://www.phys.ttu.edu/~heejong/afterpulse/02-28-2005.htm for more plots 2018-12-02

Change of the afterpulse timing distribution Day 1 Day 2 Day 3 Day 4 2018-12-02 http://www.phys.ttu.edu/~heejong/afterpulse/03-10-2005.htm

Afterpulse rate of SN1439 2018-12-02 http://www.phys.ttu.edu/~heejong/afterpulse/03-28-2005.htm for more plots

Typical Timing distribution of the afterpulse(SN1439) at HV 1200V (with respect to the leading edge of the main pulse) 2018-12-02

After pulse rate as a function of main pulse(light level) 2018-12-02

ADC count when there are no afterpulse timing hit in TDC 2018-12-02

Pedestal level ( in ADC counts) for 4 days 2018-12-02

HV dependence of the afterpulse( light level kept same) 2018-12-02

Afterpulse Timing Shift as HV changes 2018-12-02

Change of timing distribution as HV changes( light level kept same) (3 pairs of arrow indicate the gate position for ADCs) 2018-12-02

Gate position for 3th ADC was adjusted for HV 1200V setting 2018-12-02

Plans Once PMT shows stable afterpulse rates, He Gas blowing starts. Only He Gas will be provided. Other type of PMT(R580 etc) will be tested. 2018-12-02