August 8, 2006

DRAGON group meeting minutes

In attendance: DH, MT, GR, CV, PM, JZ (recorder)

Minutes of previous meeting:
         2 corrections:
                i) in the hardware section, it should state that the pressure in the 
                ceramic tubes *decreases* by 1psi/hour (the minutes currently state that it
increases)
 
                ii) 40C(a,g) contribution to NIC9 has been submitted
        
Hardware:

        Ceramic tubes:        
                - in order to be cautious, testing of how well tubes hold pressure over 24 hour
period has
                been done over 3 days (so the whole test can be observed); testing of the 3rd tube
is in 
                progress now
                -over the long weekend, the pressure dropped by ~20psi, but no water was observed
on the outside
                of the tube; this is consistent with previously observed 'mystery' pressure drop.
                - 2 stage leak testing will commence this week:
                                - stage 1: vessel @ vaccuum, look for leaks (inflow of gas)
                                - stage 2: vessel above atmospheric pressure, look for leaks (outflow)
                - 30-day deadline for us to approve the tubes expires tomorrow --> we will ask for
7-10 day extension
                so we can finish the testing
                
        Alpha-testing:
                - this will continue in EOC's absence (he is on vacation for the week)
                - CV will move DSSD to MD1 with PM's assistance
                - testing should be done this week
                
        Other:
                - J. Ressler has retrieved NaI detector borrowed from SFU
                - Height checking of quads *could* be done using a TOTAL survey station which
locates markers in 3-d space;
                this requires an "original" surver to compare with the new one. Such a survey was
not done when DRAGON was 
                being built, so this technique can't be used to check for quad height changes now. 
                We *could* use this tool, however, to check where things are 
                now, and use that as a reference if we start moving quads around. DH and MT
expressed doubts about moving quads
                
Pumping calculations:
                - current DRAGON differential pumping tubes allow ~21mrad acceptance from
point-like source at center of target;
                actual recoils can be made in upstream part of target, and beam spot size is
non-zero. Also, pumping system
                extends 85 cm from target center.
                - JZ has done some calculations and designed a system that allows for 30 mrad
acceptance with a 4mm beam spot
                diameter, and allows for recoils to be made upstream of target center (by 1cm)
                - design has target shortened to 6cm, and the pumping system ends 40cm downstream
of target center. System allows
                for 8(4)Torr He(H2) gas target, and pumps down to 2(3)E-6 Torr, using only the
existing pumps
                - the extra space liberated could be used for an extra quad doublet (cost: roughly
$60,000) or a post-stripper 
                gas cell (to allow recoils to reach charge-state equilibrium).
                - some quads already at TRIUMF (from TISOL, for example) *might* be usable; we
will need to investigate
                - a more thorough investigation of DRAGON optics will be needed (to see if adding
quads can work)
                - another design will be made that incorporates 1 new turbo pump: expect end
pressure can be reduced by one order of
                magnitude, making it 2(3)E-7 Torr with a He(H2) target at 8(4) Torr.
                
Student talks:
                - JZ and EOC gave talks at last week's student symposium
                - The consensus is that all talks were very well done
                - EOC received an honorable mention for his talk
                - JZ's talk was chosen as the winner; it will be presented at WNPPC-07
                
22Na(p,g):
                - CR's sketch of chamber was sent to UW for their input
                - Once a design has crystallized, drawings will be made at TRIUMF and UW will
machine it
                - We will wait for UW input before passing sketches on to a designer
                - DH has a new idea for target mounting; a sketch was discussed
                - More information is needed about target transport to UW:
                        - a type A container is needed --> what is it? how large is it? could we leave it
at UW after?
                - Adding more detectors (even old Ge detectors) to the experiment would reduce
pile-up, allowing for a hotter
                (more radioactive 22Na present) target to be used; this may not pose a
significantly increased safety risk and
                could improve statistics
        
Other business:
                - Letters from EEC have been sent out
                - Several DRAGON experiments have medium, medium-high, and high priority
                - 30P(p,g) has high priority but won't run until we prove that the beam can be
succesfully delivered
                - ECR for OLIS keeps getting pushed back
                - Christian has requested a high-resolution diagram of ISAC layout for a book; the
publicity will be good for DRAGON