Bio-Rad PDS-1000 / He™ and Hepta™ Systems - Manual (Page 32)

Estimate rupture disk burst pressure by observing the helium pressure gauge at the top of
the acceleration tube. A small pop will be heard when the rupture disk bursts. The rupture
disk should burst within 10% of the indicated rupture pressure and within 11–13 seconds.
Release the FIRE switch immediately after the disk ruptures to avoid wasting helium.
Releasing the FIRE switch prior to disk rupture will vent the gas acceleration tube via the
3-way helium metering (solenoid) valve.
Note: Variation in the burst pressure indicated on the helium pressure gauge (on the top
of the unit) from the rated rupture disk pressure may observed if the gas acceleration tube
fill rate is improperly set. See Section 5.4 for solenoid valve adjustment procedure.
12. Release vacuum from chamber
Release the vacuum in the sample chamber by setting the VACUUM switch to the mid-
dle VENT position.
13. Target cells removal from chamber
After vacuum is released, the vacuum gauge should read 0 inches of mercury (Hg) of
vacuum. Open the sample chamber door. Remove the sample and treat as appropriate.
14. Macrocarrier and stopping screen removal from microcarrier launch assembly
Remove the microcarrier launch assembly. Unscrew the lid and remove the macrocarri-
er holder. Discard the used macrocarrier and stopping screen (Figure 4.12).
Fig. 4.12. View of used macrocarrier and stopping screen within disassembled microcarrier
launch assembly after a bombardment.
15. Removal of spent rupture disk
Unscrew the rupture disk retaining cap from the gas acceleration tube. Remove the remains of
the rupture disk (Figure 4.13). The next bombardment may now be performed (from step 7).
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