EPD Timing by Run

Some questions about our gate settings have come up.  Here they are:

Run 22 (pp510):
                                          Actual   Default
EPD_QTb_E_Gate_End_Delay    71    48
EPD_QTb_E_Gate_Start_Delay    55    32
EPD_QTb_W_Gate_End_Delay    81    48
EPD_QTb_W_Gate_Start_Delay    65    32
EEPD_QTc_E_Gate_End_Delay    41    39
EPD_QTc_E_Gate_Start_Delay    25    23
EEPD_QTc_W_Gate_End_Delay    51    39
EPD_QTc_W_Gate_Start_Delay    35    23

Run 21 (AuAu7 and others)

EPD_QTb_E_Gate_End_Delay    48    ---
EPD_QTb_E_Gate_Start_Delay    32    ---
EPD_QTb_W_Gate_End_Delay    48    ---
EPD_QTb_W_Gate_Start_Delay    32    ---
EPD_QTc_E_Gate_End_Delay    39    ---
EPD_QTc_E_Gate_Start_Delay    23    ---
EPD_QTc_W_Gate_End_Delay    39    ---
EPD_QTc_W_Gate_Start_Delay    23    ---

Run 20 (AuAu11.5)

EPD_QTb_E_Gate_End_Delay    48    ---
EPD_QTb_E_Gate_Start_Delay    32    ---
EPD_QTb_W_Gate_End_Delay    48    ---
EPD_QTb_W_Gate_Start_Delay    32    ---
EPD_QTc_E_Gate_End_Delay    39    ---
EPD_QTc_E_Gate_Start_Delay    23    ---
EPD_QTc_W_Gate_End_Delay    39    ---
EPD_QTc_W_Gate_Start_Delay    23    ---

Run 19 (AuAu19, 14.5)

EPD_QTb_E_Gate_End_Delay    48    48
EPD_QTb_E_Gate_Start_Delay    32    32
EPD_QTb_W_Gate_End_Delay    48    48
EPD_QTb_W_Gate_Start_Delay    32    32
EPD_QTc_E_Gate_End_Delay    39    39
EPD_QTc_E_Gate_Start_Delay    23    23
EPD_QTc_W_Gate_End_Delay    39    39
EPD_QTc_W_Gate_Start_Delay    23    23

Run 18 (AuAu27 Isobar)

EPD_QT_Gate_End_Delay    48    48
EPD_QT_Gate_Start_Delay    32    32
EPD_QTc_Gate_End_Delay    39    39
EPD_QTc_Gate_Start_Delay    23    23
EPD_QTc_TAC_Stop    64    64

Page 17 of: https://drupal.star.bnl.gov/STAR/system/files/UsingRunControlEPD.pdf gives a good visual
Mike's blog on how we do the timing: https://drupal.star.bnl.gov/STAR/blog/lisa/epd-timing-scan-run-2018
The key math from this is:

  • EPD_QT_Gate_Start_delay
  • EPD_QT_Gate_Stop_delay = EPD_QT_Gate_Start_delay+16     (subtract N*108 as necessary to get in range [0,255])
  • EPD_QTc_Gate_Start_delay
  • EPD_QTc_Gate_Stop_delay = EPD_QTc_Gate_Start_delay+16     (subtract N*108 as necessary to get in range [0,255])
  • EPD_QTc_Gate_TAC_Stop = 18 + 2*EPD_QTc_Gate_Start_delay     (subtract N*2*108 as necessary to get in range [0,255])