Summary of the UK HARP Meeting held on Thursday 20th July 2000 in Sheffield

Present: Giles Barr, Craig Buttar, Rob Edgecock, Alan Holmes, Richard Nicholson, Paul Soler.

Minutes of meeting of 6th June 2000: - Not inspected during the current meeting - we should remember to review the actions of that meeting. Action: All
Review of target support arm: Giles reviewed the comments made when the target support was presented at CERN on 10 July which were:

Concern about gripping of aluminium surfaces which hold the tube within the trigger support.
Magnet moving. Rob would inquire to see if magnets are likely to move. Action: RE
Surveying - The targets are intentionally made of a large diameter (3cm) so that they do not need to be accurately surveyed and we are sure the beam is hitting them. The 'button' target allows this to be cross checked. Friedrich asked whether it is possible to SURVEY the target position accurately to be able to cross check the vertex reconstruction in the TPC (which is needed to check there are no systematic biases introduced in the pt distribution). We could not think of a way of surveying the target position accurately (which is why we opted for the large diameter target).
The preliminary design of the frame holding the chariot in place was shown. We may want to attach the frame to the magnet in case it moves.

Modification of target support arm fixing to TPC: It was decided at the meeting that the above problems were addressed and no new problems introduced by changing the mounting philosophy - which we did. Instead of using the location on the 86H7 diameter of the trigger support to hold the target support arm in place, the target support arm would be held in place by leaving it mounted on the chariot. Therefore, the target support arm would have a smaller diameter to clear the 86H7. For the September tests, a flange which is affixed to the trigger centering plate (plaque du centrage trigger) with M6 bolts would be constructed by Oxford. [Later... Lucie and Mario have approved the additional holes, the facility of locating on the 86H7 will be maintained in case needed after the experience of the September tests].
Design of support arm to target mounts: Alan and Richard designed a system involving a polythene nut for holding the target mounts onto the support arm. It was agreed to reduce the length of the support mount (Oxford) and increase the length of the target mounts (Sheffield) by 20mm (number in minutes needs checking) so that the coupling between the two components is within the trigger support tube and therefore does not define the limit of our acceptance to backward particles. The target mounts may still be 0.2mm, or may need to increase to 0.3mm since they are now longer. The target support arm will be manufactured in Newcastle.
HARP phases 2 and 3: For forward planning of PPARC funds, we are required to state our future plans fairly soon. We discussed the interest in phases 2 (He,d projectiles) and 3 (NA49) of HARP. The consensus was that HARP phase 2 was a simple, cheap extension and we were all interested in continued participation. Giles related the current status of progress with NA49. NA49 need further approval from the SPSC which they believe they can do best with their base programme and not HARP phase 3. Giles was encouraged to continue the work to come up with the arguments for HARP phase 3 in any case. It was pointed out that the favoured energies of neutrino factory running were 2GeV (CERN), 16 GeV (BNL), 24 GeV(FNAL) and 50 GeV(JPN), so it is not the case that HARP phase 3 are solely useful for atmospheric neutrinos. The NGS programme uses 400GeV which is a new energy not covered by SPY (450GeV) [Later... But the Atherton et al measurements are at 400 GeV].
The coffee, cakes and biscuits surpassed all expectations and fortified the travelers for the return trip on Branson rail. Thanks folks.
Trips to CERN: Craig - 2 weeks around 14th Aug, Richard - a few days during this period.
Hg target: We are all thinking, Rob will ask around Action: RE

Giles Barr