W. M. KECK ISOTOPE LABORATORY

Neptune Policies

The following are guidelines for operation of the Neptune facility. These guidelines have been endorsed by the Keck Isotope Lab steering committee to ensure that all users are aware of the policies in which the Neptune facility is run and how much users should expect to pay for using the instrument.

Bookings

All requests for Neptune measurement time to be made through the lab manager. Allocated time will be posted on the calendar. This may change with consultation with the users.

Priorities for Neptune use.

The priority for Neptune use is as follows:

1) UCSC PI

2) non-UCSC PI collaborating with UCSC PI

3) any outside work with potential for co-authorship

4) non-UCSC, non-collaborative work fo routside research institiution

5) pure contract work

This ordering is to be used as a guide as there may be other circumstances that would warrant users/projects of normally lower priority to be moved up in priority. This may also apply to contract work if the work is needed to generate much needed revenue.

Standards

Standards available are Pb (NIST 981 and NIST 997), Nd (La Jolla), Hf (JMC 475), Sr (NIST 987), U (NIST 4321, U010), Si (NIST 28), Se (Merck). Other standards are the responsibility of the users to provide. Some spikes are also available and these include 84Sr, 150Nd, 236U, 233U, 229Th amongst others.

Samples

All samples to be run on the Neptune must be purified. Samples that have not been passed through a chemical extraction and purification process cannot be introduced into the Neptune unless they have been approved. Simple mixes of standards may be analysed to assess interferences and mass bias effects. If in doubt about the suitability of your sample please ask Rob Franks or the lab manager. The lab manager may bill users at the assisted rate for time spent cleaning up the instrument prior to the next use if samples have not be adequately purified.

Neptune Recharge Policies

Complete table of recharge rates

Users wishing to develop a completely new isotope system will be allowed:

• 3 days of instrument use completely subsidized
• 3 days of instrument use subsidized at 50% of the applicable rate

After this initial time, instrument time will be charged at the assisted rate or the unassisted rate dependent on how much assistance is required by the user.

New users on the Neptune will be allowed three days at the unassisted rate as they become trained. Should they require assistance after this they will be charged at the assisted rate.

The number of hours which are charged start from when the plasma is ignited to when it is turned off. Should there be instrumental problems the user will not be charged for those hours provided the user was not responsible for the problem. An instrumental problem is considered when the instrument is unable to provide solution standard analyses that lie within 2 sigma of the isotope ratios already determined (see table) and similar sensitvity to previous analyses. It is the responsibility of the user to notify the lab manager as soon as possible of an instrumental problem to ensure that the user is not billed for unusable time. Failure to do this may result in instrument time being billed. Users may request that the lab manager tune the instrument to obtain acceptable solution standard analyses before running unknown samples.

If a PI or user disputes a bill for their Neptune use, the case will be assessed at a steering committee meeting for resolution. If the committee decides that the bill should be paid, the user or PI must pay the bill or forfeit the right to use the facilities in the Keck Isotope Laboratory.

Analyses performed at the assisted rate will be accompanied by an electronic copy of the raw data to which the analyses apply with the relevant QA/QC information.

All results from standard solution analyses must be returned to the lab manager for compilation. These will be available for UCSC personnel.