Howl-Mann Equation

L : equivalent standard leak rate
V : internal volume of the device package cavity
Po : atmospheric pressure absolute
Pe : pressure of exposure absolute
t1 : time of exposure to Pₑ
t2 : dwell time between release of pressure and leak detection

Tracer gas


Tracer gas is used for pressurization and detection. It is assumed not to be part of cavity initial content.

Partial pressure of {{ Pe_gas }} forced in during pressurization = {{ D(Pt1) }} {{ Pe_unit }}

Partial pressure of {{ Pe_gas }} remaining after dwell time = {{ D(Pt2) }} {{ Pe_unit }}

Reverse Calculations

Package Environment Cavity Volume : {{ V }} {{ V_unit }} Partial Pressure : 0 {{ Po_unit }} abs Equivalent Standard Leak Rate (L) {{ L }} {{ L_unit }} {{ L_gas }} Partial Pressure {{ L_gas }} = {{ Po }} {{ Po_unit }} abs Package Characteristics {{ L_gas }} Package Environment Cavity Volume : {{ V }} {{ V_unit }} Partial Pressure : 0 {{ Pe_unit }} abs Leak rate : {{ bombingLeakRate }} {{ R_unit }} {{ Pe_gas }} Partial Pressure {{ Pe_gas }} = {{ D(Pe * coefTG) }} {{ Pe_unit }} abs Bombing Start Tracer Gas ({{ Pe_gas }}) Cavity Partial Pressure : {{ D(Pt1) }} {{ Pe_unit }} abs Partial Pressure {{ Pe_gas }} = 0 {{ Pe_unit }} abs Bombing End after {{ t1 }} {{ t1_unit }} Dwell Time Start R1 (t2=0) : {{ R1AfterBombing }} {{ R_unit }} {{ Pe_gas }} Tracer Gas ({{ Pe_gas }}) Cavity Partial Pressure {{ D(Pt2) }} {{ Pe_unit }} abs Partial Pressure {{ Pe_gas }} = 0 {{ Pe_unit }} abs Loss of {{ Pe_gas }} : {{ tgLoss }} % R1 = {{ R1 }} {{ R_unit }} {{ Pe_gas }} Max Dwell Time of {{ t2 }} {{ t2_unit }} Tracer Gas ({{ Pe_gas }}) {{ Pe }} {{ Pe_unit }} abs of Air/Kr85 mixture Measured Radiation : {{ D(Kr85_RadAfterDwell) }} µCi ({{ D2(curieToCounts(Kr85_RadAfterDwell)) }} c/m) Measured Radiation : {{ D(Kr85_RadAfterBombing) }} µCi ({{ D2(curieToCounts(Kr85_RadAfterBombing)) }} c/m) Krypton 85 Mix Specific Activity : {{ kr85_mix_specific_activity.toFixed(0) }} µCi/atm-cc Kr85 concentration : {{ Kr85_ppmv.toFixed(0) }} ppmv

DISCLAIMER : Please contact Oneida Research Services, Inc. at (315) 736-5480 or Daniel Rossiter by email at djrossiter@orslabs.com for technical discussions regarding the application of the Howl-Mann equation.
28-nov-2018 v3.4

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